Mammalian exocrine secretions XV. Constituents of secretion of ventral gland of male dwarf hamster, Phodopus sungorus sungorus

Article abstract of DOI:10.1023/A:1010328331891

In a study aimed at the chemical characterization of constituents of the ventral gland secretion of the male dwarf hamster, Phodopus sungorus sungorus, 48 compounds, including saturated alcohols, saturated and unsaturated ketones, saturated and unsaturated straight-chain carboxylic acids, iso- and anteisocarboxylic acids, 3-phenylpropanoic acid, hydroxyesters, 2-piperidone, and some steroids were identified in the secretion. The position of the double bonds in γ-icosadienyl-γ-butyrolactone and γ-henicosadienyl-γ-butyrolactone, and the position of methylbranching in seven C₁₆-C₂₁ saturated ketones could not be established. Several constituents with typically steroidal mass spectra also remained unidentified. The female dwarf hamster's ventral gland either does not produce secretion or produced so little secretion that it was impossible to collect enough material for analysis.

Full text of DOI:10.1023/A:1010328331891

Journal of Chemical Ecology, Vol. 27, No. 6, 2001
MAMMALIAN EXOCRINE SECRETIONS XV.
CONSTITUENTS OF SECRETION OF VENTRAL GLAND
OF MALE DWARF HAMSTER, Phodopus sungorus sungorus
1
1
2
2
B. V. BURGER,1, D. SMIT, H. S. C. SPIES, C. SCHMIDT, U. SCHMIDT,
*
A. Y. TELITSINA,3 and G. R. GRIERSON4
1Laboratory for Ecological Chemistry
Department of Chemistry, University of Stellenbosch
Stellenbosch 7600, South Africa
2Zoological Institute, University of Bonn
Poppelsdorfer Schloss, D-53115 Bonn, Germany
3Institute of Animal Evolutionary Morphology and Ecology
Russian Academy of Sciences
Leninsky 33, Moscow 117071, Russia
4Rothmans International
Stellenbosch 7600, South Africa
(Received January 3, 2000; accepted January 30, 2001)
Abstract—In a study aimed at the chemical characterization of constituents of
the ventral gland secretion of the male dwarf hamster, Phodopus sungorus sun-
gorus, 48 compounds, including saturated alcohols, saturated and unsaturated
ketones, saturated and unsaturated straight-chain carboxylic acids, iso- and an-
teisocarboxylic acids, 3-phenylpropanoic acid, hydroxyesters, 2-piperidone, and
some steroids were identified in the secretion. The position of the double bonds
in -icosadienyl- -butyrolactone and -henicosadienyl- -butyrolactone, and
the position of methylbranching in seven C16–C21 saturated ketones could not
be established. Several constituents with typically steroidal mass spectra also
remained unidentified. The female dwarf hamster’s ventral gland either does not
produce secretion or produced so little secretion that it was impossible to collect
enough material for analysis.
Key Words—Phodopus sungorus sungorus, dwarf hamster, mammalian semio-
chemicals, mammalian pheromones, exocrine secretion, ventral gland secretion.
*To whom correspondence should be addressed.
1259
C
0098-0331/01/0600-1259$19.50/0 2001 Plenum Publishing Corporation

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BURGER ET AL.
INTRODUCTION
The dwarf hamster, Phodopus sungorus, also known as the Djungarian striped or
hairy-footed hamster, is a small rodent found on different types of steppes charac-
terized by extreme temperature differences such as the dry steppes of Mongolia,
Western Siberia, where air temperatures vary between +30 C in summer and
40 C in winter (Heldmaier, 1975), and in the eastern parts of the Lake Baikal
region (Pogosianz and Sokova, 1967), as well as on the steppes of Kazakhstan,
Manchuria, and North China (Wynne-Edwards and Lisk, 1984). The dwarf ham-
ster is unusually resistant to low temperatures (Veselofsky and Grundova, 1965).
It was found (Heldmaier, 1975) that they tolerated severe cold stress, but were less
able to withstand heat.
Phodopus belongs to the family Cricetinae, of which they are one of the
smallest species with a body length between 67 and 102 mm (Flint, 1966). Two
subspecies of the dwarf hamster are mentioned in the literature, namely P. s.
sungorus (Pallas), which is found in the western regions of their habitat, and the
eastern subspecies P. s. campbelli (Thomas). However, the majority of authors
make no distinction between the subspecies. A few minor differences between
the subspecies have been reported. P. s. campbelli is gregarious (Wynne-Edwards
and Lisk, 1984), while P. s. sungorus appears to be more solitary (Reasner and
Johnston, 1988). The seasonal pelage color change from dark grey in summer to
white in winter is, for example, also quite pronounced in P. s. sungorus (Heldmaier,
1975).
Although their cold resistance is noteworthy, the most unusual characteristic
of these hamsters is their highly photoperiodic nature. It seems that rather than
hibernate, they have adapted strategies for survival of severe winter conditions
by making use of the extreme seasonal changes in photoperiod, which are char-
acteristic of their natural habitat. During short photoperiods ( 8 hr of light), as
experienced in the Siberian winter, a reduction in body weight occurs, pelage color
changes dramatically, male testicle regression occurs and reproductive ability is
diminished (Hoffmann, 1973), sexual development is slowed down (Brackmann,
1977; Yellon and Goldman, 1984), and a reduction in the ventral gland size is also
observed (Sunderko¨tter et al., 1990).
According to Heisler (1984), the olfactory marking behavior in this hamster
includes marking with feces, urine, and secretions from the ventral gland, as well
as sand-bathing behavior, in which the animal rolls on its back, not necessarily only
in sand. The marking behavior of both males and females in neutral areas, in areas
where males had previously marked, and in areas where females had previously
marked was investigated. The marking frequency was found to be low in both
sexes and lower in females than in males. The hamsters were observed to mark the
periphery of the test area more frequently than they marked in the nonperipheral
areas, and while the males did not mark more frequently in an area that had already

MAMMALIAN EXOCRINE SECRETIONS XV
1261
been marked by a male, they did show an increased marking frequency in areas
previously marked by females.
Feoktistova (1994) investigated the behavioral responses of adult, sexually
experienced males of P. sungorus toward different olfactory cues, such as urine,
beddingmaterial, andintegumentaryskinglandsecretionsofconspecificmalesand
diestrous females. Habituation studies showed that males were able to discriminate
between the odors of males and females. The odors of urine, bedding material,
and the secretion of the sacculi, located at the opening of the cheek pouches
of conspecific males, elicited a high level of midventral gland marking, while
the same odors of females resulted in anogenital marking. The low population
density, nocturnal activity, and arid habitat of the dwarf hamster are expected to
favor marking activity in these animals. P. s. sungorus has well developed glands,
of which the ventral sebaceous gland (glandula abdominales) located along the
axis body line before the genitals, is one of the most important. The gland becomes
visible at an age of about 4 weeks, and it functions only during the reproductive
period. The hamsters use the secretion of this gland for marking their home ranges.
Incontrasttothelargevolumeofliteratureonolfactioninotherrodentspecies,
no comprehensive chemical investigation of the constituents of the secretions of the
dwarf hamster has so far been undertaken. The aim of the present study is to initiate
chemical investigations into the nature of the exocrine secretions in hamsters,
specifically in P. s. sungorus, in order to provide information that could lead to
new avenues of investigation of chemical communication systems in hamsters. It
is hoped, for example, that the compounds found in the secretions will generate
ideas as to their possible origin and/or purpose, and will enable biologists to use
them in behavioral studies. Using compounds present in the hamster secretions in
research on rodent olfactory receptors and behavior, makes much more sense than
using arbitrarily selected compounds totally unrelated to substances involved in
the semiochemical communication of these animals.
METHODS AND MATERIALS
General. Dichloromethane (1 ml) (Merck, residue analysis grade), was con-
centrated to 10 l, analyzed for impurities, and found to be pure enough for
extraction of small quantities of semiochemicals. Syringes were cleaned with this
solvent. Glassware used for the collection and extraction of samples was washed,
rinsed with distilled water, heated in an annealing oven at 500 C for at least 30 min,
and cooled immediately prior to use to remove all traces of adsorbed organic
material.
Analytical Methods. Gas chromatographic analyses were carried out with
a Carlo Erba 5300 gas chromatograph equipped with a flame ionization detector,
Grob split-splitless injector, and glass columns manufactured by the Laboratory for
Ecological Chemistry, University of Stellenbosch. Glass capillary columns, coated

1262
BURGER ET AL.
with a 0.25- m film of the apolar stationary phase PS-089-OH, which is a silanol-
terminated 95% dimethyl–5%-diphenyl siloxane copolymer, were used throughout
the study. Helium was used as carrier gas at a linear velocity of 28.6 cm/sec at 40 C.
The detector and injector were used at 280 C and 220 C, respectively. Samples
were injected in the split mode (split ratio 6 : 1) and an oven temperature of
approximately 30 C. The oven was heated ballistically to 40 C and programmed at
2 /min from 40 to 260 C (hold). Gas chromatographic retention time comparison
of the constituents of the secretion with the commercially available and synthesized
reference compounds was done by coinjection of the reference compound and
glandular extract to determine whether the component under investigation was
enriched by the reference compound.
Quantitative gas chromatographic analyses were done with the same instru-
ment and column, and data acquisition with Borwin Intuitive Chromatography
Software (JMBS Developments, 38600 Fontaine, France) using hexadecanoic acid
as external standard. Ventral gland secretion (4.8 mg) was collected, extracted with
dichloromethane as described below, and the extract concentrated to 20 l of which
1- l quantities were injected for analysis.
A Carlo Erba QMD 1000 GC-MS system was used to record electron impact
(EI) mass spectra (70 eV) employing the GC parameters specified above. The
interface temperature was maintained at 250 C. The ion source temperature was
5
200 C, and the source pressure varied between ca. 2
10 torr at a column
temperature of 40 C, decreasing to 1 10 5 torr towards the end of the temperature
program at a column temperature of 260 C. A scan rate of 0.9 scan/sec, with an
interval of 0.1 sec between scans, was employed. Chemical ionization (CI) mass
spectra with methane as reactant gas were recorded on a Finnigan 4500 quadrupole
GC-MS system. The interface temperature was 220 C, and spectra were recorded
at 60 eV and at a source temperature of 150 C. Under these conditions the pressure
in the source was approximately 7 10 5 torr. Spectra were recorded at a rate of
2 scans/sec. Accurate mass measurements of the synthetic compounds were done
on an AMD 604 magnetic sector mass spectrometer. The spectra were recorded at
an ionization potential of 70.7 eV and a source temperature of 192 C. The resolving
power was 4000, and a scan rate of 1 scan/sec was used, with a recovery time of
0.5 sec. A sampling frequency of 100 kHz was used, and the source vacuum was
5
1.4 10 torr. In the case of samples introduced on the probe, the probe was
heated from 20 to 350 C.
1H and 13C NMR spectra of synthesized compounds were obtained on a
Varian VXR-300 spectrometer at 299.9 MHz and 75.42 MHz, respectively. The
13C spectra were obtained by using a 45 pulse angle and a pulse repetition time
of 0.8 sec. Chloroform-d1 (Merck, 99.8% isotopic purity) was used as solvent and
tetramethylsilane (TMS) as internal reference.
Determination of Double Bond Positions of Constituents. Dimethyl disul-
fide (DMDS) derivatives were prepared from the unsaturated constituents of

MAMMALIAN EXOCRINE SECRETIONS XV
1263
the secretion according to the procedure described by Vincenti et al. (1987). A
dichloromethane extract of the secretion was concentrated in a Reacti-Vial using
a slow stream of purified nitrogen. The residual material was dissolved in carbon
disulfide (50 l) and treated with an excess (5- l) of a solution of iodine in ether
(60 mg/ml) and 50 l of dimethyl disulfide. The Reacti-Vial was sealed and the re-
action mixture heated in an oven at 60 C for 40 hr; then the iodine was reduced with
aqueous sodium thiosulfate solution (5%). Separation of the aqueous and organic
layers was facilitated by centrifuging the reaction mixture at 3000 rpm. The organic
layer was transferred to another vial and concentrated to 5 l for GC-MS analysis.
Sample Collection and Preparation. Djungarian dwarf hamsters, P. s. sun-
gorus, were bred from stock obtained from a breeding colony of the Zoological
Institute at the University of Bonn. All adult animals were kept indoors in sepa-
rate wire cages (36 25 23 cm) with an exercise wheel, except when males
and females were put together for breeding purposes. The animals were kept at a
constant temperature of 22 C in a laboratory free from artificial odors. To simu-
late summer conditions, the animals were exposed to natural light during daytime
(Stellenbosch 33 500 southern latitude) and, in addition, fluorescent lights were
left switched on permanently resulting in a minimum light intensity of 200 lux
during the nighttime. Each hamster was supplied with half a coconut shell that
served as a hut into which it could withdraw into almost total darkness. To avoid
contamination of the secretions with plant volatiles, shavings from old, dry poplar
logs were provided for bedding material. When breeding, animals were also pro-
vided with cellulose tissues. All bedding and cellulose materials were renewed
at weekly intervals. All hamsters were provided ad libitum with water and food
containing sunflower seeds. Twice a week they were supplied with slices of apple,
carrot, and lettuce. No problems were experienced with maintaining and breeding
the hamsters under these conditions.
Teflon stoppers and lengths of stainless-steel wire (15 0.4 mm) were washed
withdetergentsolution;rinsedwithdistilledwater, methanol, anddichloromethane,
and dried in an oven at 110 C. Using precleaned tweezers, the stainless-steel wires
were inserted into the tapered end of the Teflon stoppers. The other ends of each
of the wires were bent to form a small eyelet having a diameter of approximately
1 mm with which the secretion could be removed from the gland. Ventral gland
secretion was collected individually from mature males in their summer state on
a weekly basis. Although a hairless secretory area was clearly visible on females
in this state, they did not produce enough substance for collection. The waxy se-
cretion was collected by scooping it from the glandular area with a precleaned
stainless-steel eyelet. The Teflon stoppers were inserted into the flared ends of
small glass vials to provide an air-tight stopper for the vials The samples were
stored at 20 C for future use.
For analysis, initially the collected secretion was scraped off the wire loop and
transferred to a Reacti-Vial containing dichloromethane. However, a substantial

1264
BURGER ET AL.
proportionofthesamplewaslostinthisprocess. Tominimizethelossofsample, the
stainless steel eyelet containing the sample was therefore cut off and allowed to fall
into a Reacti-Vial containing 30 l of dichloromethane. The material was sonicated
for 20 min, and then the light brown, turbid extract was centrifuged at 2500 rpm
for 15 min in order to separate the extract into a clear dichloromethane extract
and a turbid supernatant layer. The bottom layer was removed from underneath
the supernatant layer with a 100- l syringe and transferred to a clean Reacti-Vial
in which the extract was concentrated in an inert atmosphere to a concentration
suitable for GC and GC-MS analysis.
Reference Compounds. In addition to authentic commercially available ref-
erence compounds, the following compounds were synthesized for retention time
and mass spectral comparison with constituents of the ventral secretion.
2-Heptadecanol (17); Figure 1 was prepared by NaBH4 reduction of 2-hepta-
decanone. HR-MS: m /z (M-H2O)+ 238.267, calcd. for C17H34 238.266. 13C NMR
(CDCl3): = 68.20 (d, C-2), 39.41 (t, C-3), 31.95 (t, C-15), 29.4–29.8 (t, C-6–
C-14), 29.38 (t, C-5), 25.80 (t, C-4), 23.49 (q, C-1), 22.71 (t, C-16), 14.12 (q,
C-17).
(Z)-6-Heptadecen-2-one, (Z)-8-heptadecen-2-one (13), (Z)-6-nonadecen-2-
one, (Z)-8-nonadecen-2-one (28), (Z)-10-nonadecen-2-one, (Z)-12-nonadecen-2-
one (29), and their E isomers were prepared by alkylation of ethyl acetoacetate
with the appropriate (E)- and (Z)-alkenyl bromides, hydrolysis of the condensation
product, and decarboxylationof the resulting -ketoacidaccordingtothe following
procedure described for the preparation of (Z)-8-nonadecen-2-one.
A solution of tetrabromomethane (41.5 mg, 0.125 mmol) in dry acetonitrile
(230 l) was added to a solution of (Z)-5-hexadecen-1-ol (30 mg, 0.125 mmol)
(Pherobank, Wageningen, The Netherlands) and triphenylphosphine (32.8 mg,
0.125 mmol) in acetonitrile (230 l) in a 3-ml Reacti-Vial at room temperature
and the reaction mixture stirred magnetically at room temperature for 24 hr. The
resulting bromide and traces of unchanged starting compounds were extracted
with n-pentane from the acetonitrile by magnetically stirring the reaction mix-
ture with the n-pentane (300 l), centrifuging the mixture at 1000 rpm for a few
minutes and removing the supernatant pentane layer with a 500- l syringe. The
extraction was repeated five times. The reaction product was purified by bulb-
to-bulb distillation to give (Z)-1-bromohexadec-5-ene, 36 mg (95%) bp 102 (air
4
bath)/7.5 10 mm Hg. The alkenyl bromide, containing less than 0.1% of the
unchanged 5-hexadecen-1-ol as the only impurity (GC-MS), was used to alkylate
ethyl acetoacetate. Ethyl acetoacetate (1.35 g, 10.4 mmol) was deprotonated by
adding it to a solution of sodium ethoxide (10.4 mmol) in absolute ethanol (50 ml).
The resulting anion was alkylated by magnetically stirring a sample (600 l) of
this solution in a 3-ml Reacti-Vial with (Z)-1-bromohexadec-5-ene (36 mg, 0.119
mmol) at 90 C for 11 hr during which time a precipitate of NaBr was formed. The
ethanol was evaporated at room temperature by using a slow stream of purified

MAMMALIAN EXOCRINE SECRETIONS XV
1265
FIG. 1. Structures of representative examples of the compounds identified in the ventral
secretion of the male dwarf hamster, Phodopus sungorus sungorus.

1266
BURGER ET AL.
argon, after which the ethyl ester was hydrolyzed by stirring the residue in the
Reacti-Vial with NaOH solution (1.5 M, 200 l, 0.3 mmol) at room temperature for
24 hr. The unsaponified material and unchanged bromide were extracted twice with
n-pentane (300 l) by stirring the reaction product with the solvent, centrifuging
the mixture at 1000 rpm, and removing the supernatant organic layer with a 500-
l syringe. The saponified material was acidified with H2SO4 (1.5 M) and the
resulting ketoacid decarboxylated by heating the reaction mixture at 90 C until
no further formation of gas bubbles in the Reacti-Vial (closed with a screw cap)
could be observed. The organic material was extracted three times with n-pentane
and washed free from H2SO4 with distilled water. Slow evaporation of the solvent
gave (Z)-8-nonadecen-2-one (28) as a colorless oil (3.8 mg) containing 2.5% of
the E isomer (GC-MS). 13C NMR (CDCl3): = 209.24 (s, C-2), 130.22 (d, C-9),
129.48 (d, C-8), 43.78 (t, C-3), 31.93 (t, C-17), 29.85 (q, C-1), 29.77–28.83 (t,
C-5, C-6, C-11–C-16) 27.25 (t, C-7)*, 27.03 (t, C-10)*, 23.79 (t, C-4), 22.69 (t,
C-18), 14.11 (q, C-19) (* assignments interchangeable).
1-Hydroxyhexadec-2-yl pentanoate (47) and 2-Hydroxyhexadec-1-yl pen-
tanoate (48) were prepared by the Al2O3-catalyzed reaction of 1,2-epoxyhexa-
decane with pentanoic acid as described by Burger et al. (1999a). The two isomers
were formed in a ratio of 3 : 2. HR-MS (mixture of the two isomers): m /z M+
342.309, calcd. for C21H42O3 342.313. Major component: 13C NMR (CDCl3):
= 174.37(s, C-1), 75.50 (d, C-20), 64.99 (t, C-10), 34.30 (t, C-2), 31.95 (t, C-140),
30.56 (t, C-30), 29.4–29.7 (t, C-50–C-130), 27.16 (t, C-3), 25.33 (t, C-40) 22.72 (t, C-
150), 22.28 (t, C-4), 14.13 (q, C-160), 13.72 (q, C-5). Minor component: 13C NMR
(CDCl3): = 174.05 (s, C-1), 70.10 (d, C-20), 68.58 (t, C-10), 33.96 (t, C-2), 33.40
(t, C-30), 31.95 (t, C-140), 29.4–29.7 (t, C-50–C-120), 29.38 (t, C-130), 27.05 (t, C-3),
25.39 (t, C-40), 22.72 (t, C-150), 22.28 (t, C-4), 14.13 (q, C-160), 13.72 (q, C-5).
2-Piperidone (1). Cyclopentanone oxime was dried over phosphorus pen-
toxide and subjected to Beckmann rearrangement in concentrated H2SO4 to give
2-piperidone ( -valerolactam) (Becker et al., 1973). HR-MS: m /z M+ 99.066,
calcd. for C5H9NO 99.068. 13C NMR (CDCl3): = 172.65 (s, C-1), 42.20 (t,
C-5), 31.51 (t, C-2), 22.28 (t, C-4), 20.88 (t, C-3).
RESULTS AND DISCUSSION
A typical total ion chromatogram of an extract of the ventral secretion of
a male dwarf hamster is given in Figure 2 and the compounds identified in the
secretion are listed in Table 1. Mass spectral data are given for only a few typical
examples of the different compound classes present in the secretion, because the
spectra of compounds within each class are quite similar and the spectral data of
these typically long-chain compounds contain relatively little structural informa-
tion. The structures of representative examples of each compound type are given

MAMMALIAN EXOCRINE SECRETIONS XV
1267
FIG. 2. Total ion chromatogram of an extract of the ventral secretion of a male dwarf
hamster, Phodopus sungorus sungorus.
in Figure 1. Tentative identification of the constituents of the secretion was based
on low-resolution EI mass spectra and CI mass spectral information obtained with
methane as reactant gas. Final confirmation of many of the proposed structures
was obtained by co-injection of an extract of the secretion with authentic synthetic
material.
It is not possible to determine unequivocally the position of double bonds in
unsaturated ketones from the low-resolution mass spectral data of their dimethyl
disulfide (DMDS) adducts, because one CO and two CH2 groups are isobaric,
so that the DMDS derivative of one alken-2-one can give rise to two diagnostic
ions with the same nominal masses (although having different accurate masses) as
those from another isomeric DMDS derivative. Both the E and Z isomers of each
of the pairs of alken-2-ones had therefore to be synthesized for retention-time
comparison. There appeared to be two series of unsaturated ketones present in
the secretion, one with the double bond in the 8 position and another one with the
double bond equidistant from the methyl terminal end of the ketones. Although the
position of the double bond of the unsaturated ketone 19 could not be determined,
it is quite likely that it belongs to the first of these series and could therefore be
(Z)-8-octadecen-2-one.
Although several presumably methyl-branched 2-alkanones having spectra
similar to those of the unbranched ketones are present in the secretion, these
compounds are present in such low concentrations that it was impossible to de-
termine the position of the methyl branching from the available mass spectral
data. The molecular masses of some of these ketones could be established from

1268
BURGER ET AL.
TABLE 1. COMPOUNDS IDENTIFIED IN VENTRAL SECRETION OF DWARF
HAMSTER
Peak
EI Mass spectral data,
Quantity
(Figure 1)
Compound
1-Hexadecanola,c
m /z (%)
(ng/animal)
15
0.04
c
17
31
2-Heptadecanola
2-Nonadecanola
0.3
0.5
c
266(0.4), 238(0.5), 227(0.4), 181(0.5),
168(0.5), 154(0.8), 140(1), 125(1),
111(7), 97(18), 83(19), 7(15), 69(18),
57(33), 55(30), 45(100), 43(47)
43
26
2-Henicosanola,d
0.05
1.3
Hexadecane-1,2-diola
227(15), 125(7), 117(6), 111(24),
97(58), 83(73), 71(38), 69(75), 61(22),
57(82), 55(88), 43(100), 41(75)
c
c
32
Heptadecane-1,2-diola
2-Tridecanonea,b,c,e
7.1
4
5
9
0.1
0.4
0.05
0.2
2-Pentadecanonea
2-Hexadecanonea
d
d
d
16
2-Heptadecanonea
254(2), 239(1), 196(2), 194(2), 152(1),
138(1), 127(3), 96(7), 85(15), 71(44),
59(68), 58(100), 55(25), 43(97),
41(30)
23
30
37
42
52
6
12
20
27
2-Octadecanonea,b,d,e
2-Nonadecanonea,d
2-Icosanonea,b,d
2-Henicosanonea,b,c
2-Tricosanonea,b,d
Branched 2-hexadecanonea,b,d
Branched 2-heptadecanonea,b,d
Branched 2-octadecanonea,b,d
0.3
4.9
0.1
1.2
0.2
0.1
0.2
1.0
0.3
Branched 2-nonadecanonea,b,d 282(1), 224(0.1), 220(1), 96(5),
85(10), 71(38), 59(72), 58(100),
55(22), 43(100), 41(25)
35
39
36
8
13
14
19
22
28
Branched 2-icosanonea,b,d
2.2
0.1
0.3
0.06
0.02
0.05
0.09
0.07
0.7
Branched 2-henicosanonea,b,d
Branched 2-icosanonea,b,d
(Z)-8-Hexadecen-2-onea,b,d
(Z)-8-Heptadecen-2-onea
d
(Z)-10-Heptadecen-2-onea,b,d
(Z)-8-Octadecen-2-onea,b, f
(Z)-11-Octadecen-2-onea,b,d
(Z)-8-Nonadecen-2-onea
280(0.2), 265(0.1), 262(0.2), 222(1),
198(2), 184(1), 152(2), 135(4), 125(10),
111(8), 97(17), 96(15), 82(19), 81(18),
71(33), 58(25), 55(43), 43(100), 41(39)
d,g

MAMMALIAN EXOCRINE SECRETIONS XV
1269
TABLE 1. (Continued)
Peak
EI Mass spectral data,
Quantity
(Figure 1)
Compound
m /z (%)
(ng/animal)
d,g
29
40
41
(Z)-12-Nonadecen-2-onea
0.6
0.2
0.2
(Z)-8-Henicosen-2-onea,b,d,g
(Z)-14-Henicosen-2-onea,b,d,g
c
21
34
45
Hexadecanoic acida
4.9
2.2
0.5
d
Octadecanoic acida
Icosanoic acida,c,d
312(6), 269(3), 213(3),
185(4), 171(3), 157(1),
143(2), 129(20), 115(7),
97(18), 83(23), 73(65),
71(33), 61(20), 60(65),
57(69), 55(68), 43(100),
41(58)
d
53
55
10
18
24
Docosanoic acida
0.2
0.1
0.3
0.1
0.6
Tetracosanoic acida,c,d
13-Methyltetradecanoic acida
d
14-Methylpentadecanoic acida,c,d
15-Methylhexadecanoic acida
270(4), 227(6), 125(4),
171(3), 157(1), 143(2),
129(16), 115(6), 97(15),
83(20), 73(61), 71(26),
69(35), 61(15), 60(60),
57(58), 55(59), 43(100),
41(67)
d
d
38
44
49
7
17-Methyloctadecanoic acida
0.1
0.1
0.2
0.2
0.1
18-Methylnonadecanoic acida,c,d
19-Methylicosanoic acida
d
11-Methyltridecanoic acida
d
d
25
14-Methylhexadecanoic acida
270(4), 241(2), 227(3),
213(3), 185(4), 171(4),
157(3), 139(5), 129(16),
111(10), 97(23), 83(28),
73(55), 71(35), 69(44),
61(10), 60(55), 57(87),
55(98), 43(100), 41(86)
282(0.4), 264(2), 256(0.5),
227(0.7), 222(1), 213(1.5),
151(2), 137(3), 123(5),
111(10), 97(30), 83(42),
73(27), 69(65), 67(33),
60(25), 57(42), 55(100),
43(80), 41(88)
e,g
33
(Z)-9-Octadecenoic acida
0.8
3
3-Phenylpropanoic acida,c,e
150(27), 131(3), 104(44),
91(100), 79(10), 118(20),
77(24), 65(17), 51(20), 39(13)
0.2
(Continued)

1270
BURGER ET AL.
TABLE 1. (Continued)
Peak
(Figure 1)
EI Mass spectral data,
m /z (%)
Quantity
(ng/animal)
Compound
c,e
c,e
47
48
50
1-Hydroxyhexadec-2-yl pentanoatea
2-Hydroxyhexadec-1-yl pentanoatea
0.2
0.4
0.5
1-Hydroxyheptadec-2-yl pentanoatea,b,e 255(0.5), 227(2), 157(0.5),
116(8), 101(10), 85(100),
69(13), 57(48), 55(23),
48(48), 41(25)
51
2-Hydroxyheptadec-1-yl pentanoatea,b,e 323(0.5), 241(2), 145(5),
116(25), 101(45), 85(100),
0.8
69(20), 57(58), 55(24),
43(52), 41(33)
54
58
62
2-Hydroxyicos-1-yl acetatea,c,e
4-(Hexadecadien-1-yl)-butanolidea,e, f,h
4-(Heptadecadien-1-yl)-butanolidea,e, f,h 376(1), 358(0.5), 332(0.5),
221(1), 166(1), 151(2),
0.1
0.8
0.7
125(5), 111(16), 97(37),
85(100), 83(42), 69(50),
57(72), 55(75), 43(89), 41(53)
99(100), 70(30), 58(7),
56(15), 55(38), 43(65),
42(78), 41(59), 30(89)
c,e
1
2-Piperidonea
Unidentifieda,b
Cholesterola
Unidentifieda
Unidentifieda
Unidentifieda
Unidentifieda
Unidentifieda
1.0
2
59
56
57
60
61
63
64
65
46
0.3
5.6
0.3
0.4
0.2
1.0
1.3
0.5
0.2
0.9
c,e
Desmosterola,c,e
Lanosterola,e,i
Unidentifieda,b
aLow resolution EI mass spectral data.
bCl(CH4) mass spectral data.
cRetention time comparison.
d Relative retention time interval comparison.
ePublished data.
f Position of double bond uncertain.
gEI mass spectral data on DMDS derivative.
hConfiguration of double bond uncertain.
i Tentative identification.
their Cl(CH4) mass spectra. The secretion contains unbranched as well as iso-
and anteiso-branched fatty acids and it is, therefore, quite likely that most of the
branched 2-alkanones could also be the iso ketones, while the unidentified ketone
36 could be 18-methyl-2-nondecanone. The retention-time increments observed

MAMMALIAN EXOCRINE SECRETIONS XV
1271
for the branched and unbranched carboxylic acids, for example, those between the
C20 and C17 acids, correlate very well with the increments between the branched
and unbranched ketones and therefore appear to confirm this assumption. Unfor-
tunately, it was not possible to determine the position of the double bonds in the
two -lactones 58 and 62. As can be expected, their mass spectra do not contain
the required structural information and their DMDS derivatives could not be found
in the total ion chromatogram of a sample of the secretion subjected to DMDS
derivatization, probably because the high masses of the derivatives precluded their
elution from the capillary column.
According to its Cl(CH4) mass spectrum, constituent 2 has a molecular mass
of 166, and the compound apparently has an acetyl function. Its mass spectrum
is similar to that of 1-acetylhydrindane, which also has a molecular mass of 166.
However, the mass spectrum of this constituent has a prominent ion at m /z 109
(23%), whichisrelativelyweakintheNBSlibraryspectrumof1-acetylhydrindane.
Furthermore, the mass spectrum of the constituent 2 does not have an ion at m /z
148 which is present in the library spectrum. This constituent is, therefore, listed
as unidentified in Table 1.
All of the constituents eluting in the high-molecular-weight range of the total
ion chromatogram appear to be steroids. Some of these compounds remained
unidentified in the present investigation and will be subjected to further scrutiny
in future research on the dwarf hamster, because of their possible involvement in
the chemical ecology of the animal.
Varying quantities of ventral secretion were collected from individual males.
Table 1 contains quantitative data obtained from a rather large quantity (4.8 mg) of
secretion collected from one male animal. These data are included merely to serve
as a guideline for biologists planning behavioral studies on the dwarf hamster. The
variation in the quantity of ventral secretion collected from individual animals,
the probably incomplete extraction of, especially, the more polar compounds with
a small volume of dichloromethane, and the fact that different samples of the
secretionpossiblycontaindifferentconcentrationsofmoisturethatisnotdetectable
by FID are considered to be responsible for a larger factor of uncertainty than the
use of an external standard and the unaccurate determination of the volume to
which the sample was finally concentrated.
Carboxylic acids have been identified in many mammalian exocrine secre-
tions. The longer-chain acids seem to be less common, especially in secretions
investigated during the 1960s and 1970s, possibly because long-chain acids did
not elute from some of the stationary phases and packed columns used during
the earlier years of gas chromatography, or eluted as such broad peaks as to be
almost undistinguishable from the baseline. Fatty acids were found in the anal
sac secretions of many carnivores (Albone, 1984a) and in many other mammalian
secretions. The preputial gland secretion of the musk rat, Ondatra zibethica, for
example, contains a number of saturated, monounsaturated, and diunsaturated,

1272
BURGER ET AL.
C12–C20 fatty acids (Ritter et al., 1982). Fatty acids are also found in human vagi-
nal secretions (Huggins and Preti, 1976) and in the interdigital secretion of the
reindeer, Rangifer tarandus (Brundin et al., 1978). Many of the short-chain acids
found in these secretions are iso- or anteiso-branched. 3-Phenylpropanoic acid 3
was identified, among others, in the anal sac secretion of the red fox, Vulpes vulpes,
and the lion, Panthera leo (Albone and Eglinton, 1974), and in the urine of coyote,
Canis latrans (Murphy et al., 1978).
Long-chain carboxylic acids (C15–C25) were found in the occipital secretion
of the bactrian camel, Camelus bactrianus, together with some shorter-chain acids
(Ayorinde et al., 1982). Long-chain fatty acids are particularly abundant in the
interdigital secretions of bontebok, Damaliscus dorcas dorcas, and blesbok, D.
d. phillipsi, containing the saturated unbranched C6–C8, C10, C12, C14–C18, and
C20 fatty acids (Burger et al., 1999a). With the exception of the C7, C8, C10, and
C20 homologs, these acids are also present in the preorbital gland secretions of
these two subspecies, which also contain the C19 acid (Burger et al., 1999b). The
interdigital secretions of these two subspecies also contain oleic acid (Z9-C18). The
preorbital secretion of the grysbok, Raphicerus melanotis, contains the C14–C18
and C20 fatty acids (Burger et al., 1996) and that of the steenbok, R. campestris,
C8, C10, C12, C14–C16, C18, C20, and unsaturated fatty acids (Burger et al., 1999c).
Only the three C16–C18 fatty acids are present in the preorbital secretion of the
oribi, Ourebia ourebi (Mo et al., 1995) and the C8, C10, C12, C14–C16, C18, C20
fatty acids and several unsaturated analogs in the preorbital secretion of the grey
duiker, Sylvicapra grimmia (Burger et al., 1990).
With a few exceptions, long-chain alcohols have not been found in many
mammalian exocrine secretions. The identification of the C12, C14, C16, and C18
alkanols in human vaginal secretions (Huggins and Preti, 1976) is one of these
examples. Of the four long-chain C16, C17, C19, and C21 alkanols (15, 17, 31, and
43) present in the ventral secretion of the dwarf hamster, the C16 and C21 alkanols
have been identified in the interdigital secretion of the bontebok and blesbok
(Burger et al., 1999a), and the C16 alkanol in the preorbital secretion of the steenbok
(Burger et al., 1999c), as well as in the tarsal volatiles of the reindeer, Rangifer
tarandus tarandus (Andersson et al.,1975). Although the preorbital secretion of
the grysbok contains at least 22 alkanols, alkenols, and alkadienols (Burger et al.,
1996), the four alkanols found in the ventral secretion of the dwarf hamster are not
among them.
Ketones are reasonably common in mammalian exocrine secretions, and
Albone (1984b) has cited several examples of secretions containing a few short- to
medium-chain ketones. Jemiolo et al. (1987) have found several saturated, unsat-
urated, and methyl-branched unsaturated ketones in the urine of the house mouse,
Mus musculus. The ventral secretion of the dwarf hamster, however, seems to be
unique in that it contains at least 25 alkan-2-ones and alken-2-ones from C13 to
C23. Only a few of the shorter-chain members of the group of ketones present in

MAMMALIAN EXOCRINE SECRETIONS XV
1273
the ventral secretion of the dwarf hamster were found in other animals, for ex-
ample, 2-pentadecanone (5) and 2-heptadecanone (16) in the perineal secretion
of the guinea pigs, Cavia aperea and C. porcellus (Wellington et al., 1979) and
pentadecan-2-one in the dorsal secretion of the springbok, Antidorcas marsupialis,
(Burger et al., 1981).
Unfortunately, the position of the double bonds in the two monounsaturated
-lactones (58 and 62) could not be determined. One is immediately reminded
of a similar compound, (Z)-6-dodecen-4-olide, that was identified as a compo-
nent of the extract of the male tarsal hair tuft of the black-tailed deer, Odocoileus
hemionus columbianus (Brownlee et al., 1969) and later shown to originate from
the urine of the animal (Mu¨ller-Schwarze et al., 1978). The same compound was
identified in the interdigital secretions of the bontebok and blesbok, secretions
that also contain the -lactone, dodecan-5-olide (Burger et al., 1999a). The abso-
lute configuration of this compound in the bontebok has not yet been established.
Hexadecan-5-olide and its C17 and C18 homologs are present in the preorbital se-
cretion of the bontebok and blesbok (Burger et al., 1999b). Dodecan-4-olide has
been found in the occipital secretion of the bactrian camel (Ayorinde et al., 1982),
the - and -lactones, pentan-4-olide, hexan-4-olide, and hexan-5-olide, have been
identified in human urine (Zlatkis and Liebich, 1971); and the C8–C12 -lactones
in human skin lipids (Labows et al.,1979). The C15–C18 and C20 alkan-4-olides
and C16 alkan-5-olide were identified in the preorbital secretion of the grysbok
(Burger et al., 1996) and the C16 and C18 alkan-4-olides in the preorbital secretion
of the grey duiker (Burger et al., 1990).
Albone (1984c) discussed the possibility that 2-piperidone identified in the
anal sac secretions of the dog, Canis familiaris, coyote, C. latrans, and mink,
Mustela vison, could possibly be formed by the elimination of water from the
precursor 5-aminovaleric acid that is formed by fermentation processes in the anal
sac (Albone et al., 1976). 2-Piperidone has also been identified in human vaginal
secretions (Huggins and Preti, 1976).
The ventral secretion of the dwarf hamster contains five long-chain hydroxy-
esters; 47, 48, 50, 51, and 54. Although these hydroxyesters are not accompanied
by long-chain epoxides in the ventral and other secretions, it is nevertheless ac-
cepted as a working hypothesis that they are formed through nucleophilic substi-
tution of the corresponding epoxides by the corresponding carboxylic acids. The
preorbital secretion of the grysbok contains 2-hydroxyoctadecan-1-yl acetate and
2-hydroxyicosan-1-yl acetate (Burger et al., 1996). The related steenbok’s preor-
bital secretion contains 17 of these hydroxyesters, from 2-hydroxyheptadecan-1-
yl acetate to 1-hydroxydocos-2-yl butanoate and 2-hydroxydocos-1-yl butanoate
(Burger et al., 1999c), and the interdigital secretions of the bontebok and blesbok
contain 12 hydroxyesters, from 2-hydroxyoctadecan-1-yl acetate to 2-hydroxy-
docosan-1-yl butanoate (Burger et al., 1999a). It is not clear whether these com-
pounds have any semiochemical function because they are not very volatile.

1274
BURGER ET AL.
Similarly it is not clear whether steroids such as the ubiquitous cholesterol, its
derivative desmosterol, and lanosterol have a semiochemical function other than,
possibly, serving as controlled-release carrier materials. Cholesterol and desmos-
terol have also been identified in the interdigital secretions of bontebok and blesbok
(Burger et al., 1999a).
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