Reference

Selective release of follicle-stimulating hormone by 5a-dihydroprogesterone in immature ovariectomized estrogen-primed rats

Selective release of follicle-stimulating hormone by 5a-dihydroprogesterone in immature ovariectomized estrogen-primed rats. Murphy, Laura L.; Mahesh, Virendra B. (Dep. Endocrinol., Med. Coll. Georgia, Augusta, GA 30912, USA). Biol. Reprod., 30(3), 594-602 (English) 1984.Several reagents with their cas registry numbers 50-28-2 and 57-83-0 are used here. CODEN: BIREBV. ISSN: 0006-3363. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Treatment of immature acutely ovariectomized rats with various doses of 5a-dihydroprogesterone (5a-DHP) [566-65-4] in combination with estradiol [50-28-2] increased levels of FSH [9002-68-0] but had no effect on serum LH [9002-67-9]. A single injection of a maximally stimulating dose of 5a-DHP (0.4 mg/kg) stimulated increases in serum FSH at 1200 h and at 1800 h. Pituitary LH and FSH content was dramatically enhanced by 1600 h and levels remained elevated at 1800 h. The administration of pentobarbital at 1200 h, vs. 1400 h or 1600 h, prevented the increase in basal serum FSH levels at 1800 h, implying that the release of hypothalamic LH-RH [9034-40-6] is modulated by 5a-DHP. In addn., changes in pituitary sensitivity to LH-RH as a result of 5a-DHP were measured and a significant increase in the magnitude of FSH release was obsd. at 1200 h and 1800 h. Although the LH response to LH-RH in 5a-DHP-treated rats was not different from controls, the duration of LH release was lengthened. Thus, 5a-DHP may stimulate FSH release by a direct action at the pituitary level. 5a-DHP apparently mediates the facilitative effect of progesterone [57-83-0] on FSH secretion with an action at both pituitary and hypothalamic sites. .

Binding of [3H]-progesterone to normal and neoplastic tissue samples from tumor bearing breasts

Binding of [3H]-progesterone to normal and neoplastic tissue samples from tumor bearing breasts. Pollow, Kunhard; Sinnecker, Rainer; Schmidt-Gollwitzer, Manfred; Boquoi, Elmar; Pollow, Barbara (Frauenklin. Charlottenburg, Freie Univ. Berlin, Berlin, Ger.). J. Mol. Med., 2(1), 69-82 (English) 1977. CODEN: JMMEDM. DOCUMENT TYPE: Journal CA Section: 2 (Hormone Pharmacology) Macromol. components of normal human mammary cytosol (obtained from "non-malignant tissue samples" from cancer bearing breasts) which bind 3H-labeled progesterone (I) [57-83-0] in vitro were characterized by sucrose gradient centrifugation, gel filtration on Agarose, ion exchange chromatg., isoelec. focusing, competition studies and kinetic parameters. The size of the cytoplasmic binding components varied with the concn. of KCl. In the absence of KCl, the major components were characterized by sedimentation coeffs. of about 4 S and 8 S. In solns. contg. 0.3 M KCl, the cytoplasmic components sedimented at 4 S in sucrose gradient. The corticosteroid-binding globulin (CBG) and the major I binding component of normal human mammary cytosol both sedimented at about the same rate in the presence of 0.3 M KCl and chromatographed as a single component on Agarose.There are some reagents with their cas registry numbers 57-83-0 and 520-85-4 are used in this study. The isoelec. point of the I-binding component of normal human mammary cytosol was located around pH 5.0. The I-binding component was more thermo-labile than serum CBG. CBG was inactivated at temps. above 45.degree. but temp. above 20.degree. destroyed sp. I receptor binding. Competition of various progestational and non-progestational steroids to the I binding sites in the human mammary I receptor was studied. The relative affinity of the competitors was: I > 5.alpha.-dihydroprogesterone [566-65-4] >medroxyprogesterone [520-85-4]. Cortisol and 20.alpha.-dihydroprogesterone did not decrease the binding capacity. No competition with I-3H for the binding sites was obsd. when testosterone or 17.beta.-estradiol were studied. I receptor concns. in normal mammary cytosol of premenopausal women depended on the day of the menstrual cycle. The binding of I was highest around the time of ovulation. In breast tumor tissue samples the I receptor concn. was lower than in the normal mammary cytosol (obtained in each case from the same tumor-bearing breast). In 5 out of 37 breast tumor samples I binding activity was not to be detected. The assocn. consts. for I were estd. to be between 0.51 and 5.08 .cntdot. 109 M-1. .