Reference

In vivo progestogen release from implants

In vivo progestogen release from implants. Chauhan, P. S.; Varma, K. C. (Dep. Pharm. Sci., Univ. Saugar, Sagar 470 003, India). Indian J. Pharm. Sci., 48(6), 203-4 (English) 1986. CODEN: IJSIDW. ISSN: 0250-474X. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) Section cross-reference(s): 2 In vivo release rates of progestogens, levonorgestrel [797-63-7], norethindrone [68-22-4], megestrol acetate [595-33-5], and lynestrenol [52-76-6], from poly(di-Me siloxane) rod and capsule implants were detd. by recovering the implants which had been placed in rats and detg. the amt. of the progestogen lost. Levonorgestrel showed the greatest variation in release rates. Release from capsules was nearly zero order. The decrease in the release rate after 100 days was <1.5% and amounted to ￡5% even after 300 days. Release rates from the rods showed a continuous fall amounting to 50% over the same period.

Effects of steroids with different endocrine profiles on the development, morphology and function of the bursa of Fabricius in chickens

Effects of steroids with different endocrine profiles on the development, morphology and function of the bursa of Fabricius in chickens. Verheul, H. A. M.; Tittes, E. V.; Kelder, J.; Schuurs, A. H. W. M. (Organon Sci. Dev. Group, Oss, Neth.). J. Steroid Biochem., 25(5A), 665-75 (English) 1986. CODEN: JSTBBK. ISSN: 0022-4731. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 12, 15 The effect of various steroids on the anlage of the bursa of Fabricius was examd. in chickens. The steroids were administered by dipping embryonated eggs on the 3rd day of incubation in ethanolic solns. of these steroids. The results with about 30 different steroids show that the capacity to inhibit the development of the bursa does not correlate with the endocrine properties of these steroids as measured in routine screening tests for androgenic, anabolic, progestational, and estrogenic activities or with the relative binding affinities for various endocrine receptors. More elaborate studies with several representative steroids show that testosterone [58-22-0] (10 mg/mL), nandrolone [434-22-0] (10 mg/mL), 11a-hydroxynandrolone [2133-53-1] (10 mg/mL), ethylestrenol [965-90-2] (1 mg/mL), lynestrenol [52-76-6] (1 mg/mL), and Org OD14 (tibolone) [5630-53-5] (0.1 mg/mL) induced histomorphol. changes in the remaining bursa tissue still present in 10-day- and 53-day-old chickens and in the bursa-dependent sites of their spleens (53-day-old chickens only). Testosterone and lynestrenol induced smaller changes than nandrolone or ethylestrenol. Tibolone and 11a-hydroxynandrolone were more effective than nandrolone. All drugs, except testosterone and lynestrenol, impaired antibody formation to Newcastle disease virus and decreased the serum levels of total IgG, but not of total IgM. These effects were not correlated with endocrine properties. In other studies, several of these steroids, notably tibolone, favorably influence of course of spontaneous autoimmune diseases of NZB/W mice and Obese Strain chickens. Since this autoimmunosuppression is likely to be caused by inhibitory effects on bursa or bursa equiv., this approach may be used for developing medically useful autoimmunosuppressive steroids with minimal endocrine effects.