Reference

Interactions of various 19-nor steroids with human placental microsomal cytochrome P-450 (P-450hpm)

Interactions of various 19-nor steroids with human placental microsomal cytochrome P-450 (P-450hpm). Juchau, Mont R.; Mirkin, David L.; Zachariah, Prince K. (Sch. Med., Univ. Washington, Seattle, Wash., USA). Chem.-Biol. Interact., 15(4), 337-47 (English) 1976. CODEN: CBINA8.In this article, certain chemicals are used. Some of their cas registry numbers are 360-70-3 and 434-22-0 DOCUMENT TYPE: Journal CA Section: 2 (Hormone Pharmacology) Each of 7 19-norsteroids exhibited the capacity to facilitate the binding of CO to human placental microsomal cytochrome P-450 [9035-51-2] although quant. differences were shown to exist. In every case the facilitation was antagonized by androst-4-ene-3,17-dione [63-05-8]. 19-Norandrost-4-ene-3,17-dione (I) [734-32-7] produced the most pronounced effect followed by 19-nortestosterone [434-22-0], nandrolone 17-decanoate [360-70-3], norethandrolone [52-78-8], norgestrel [6533-00-2], norethynodrel [68-23-5], and norethindrone [68-22-4] in that order. All steroids investigated produced typical type I binding spectra when added to placental microsomes. Scatchard plots also indicated binding of each steroid to 2 sites-a high-affinity, low-capacity binding site and a low-affinity, high-capacity binding site. Correlations between affinity for either site and capacity to facilitate binding of CO to the cytochrome were not obsd. nor were there good correlations between maximal absorbance differences (.apprx.390-420 nm) producible and facilitation capacity. The capacity to facilitate CO binding appeared to reside in the absence of a chem. group substituted at the 10 position on mols. of androgenic steroids since all investigated steroids possessing 10-methyl or other 10-substituted groups either had no effect on the CO-binding spectrum or caused a displacement of CO from ferrous heme. In contrast, all steroids studied that lacked a substitution at C-10 (19-norsteroids) produced a facilitating effect on heme-ligand binding. .

Presence of 19-norandrostenedione and 19-nortestosterone in human and equine follicular fluid

Presence of 19-norandrostenedione and 19-nortestosterone in human and equine follicular fluid. Incidence on the accuracy of radioimmunoassay of some androgens. Dehennin, L.; Silberzahn, P.; Reiffsteck, A.; Zwain, I. (Fond. Rech. Hormonol., Paris 75014, Fr.). Pathol. Biol., 32(8), 828-9 (French) 1984. CODEN: PTBIAN. ISSN: 0031-3009. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) The level of 19-nortestosterone (NT) [434-22-0] in the follicular fluid of women and mares was always greater than that of testosterone (T) [58-22-0]. This fact plus the 12% cross-reaction of NT with anti-T antiserum and the impossibility of sepg. NT from T by simple low-resoln. chromatog. indicated that the RIA detns. of T in follicular fluid are most often inaccurate. For similar reasons, RIA can not be used for the detn. of low concns. of follicular androstenedione (A) [63-05-8] and is often inaccurate for the detn. of high concns. of A. The correlation between the NT/T ratio and the ratio of T detd. by RIA to T detd. by gas chromatog.-mass spectrometry in human and equine follicular fluid and that between the 19-norandrostenedione [734-32-7]/A ratio and the ratio of A detd. by RIA to A detd. by gas chromatog.-mass spectrometry in human follicular fluid confirmed the interference of NT and 19-norandrostenedione in the RIA detns. of T and A, resp.