Reference

Immunoreactive luteinizing hormone releasing factor in pituitary stalk blood from female rats: sex steroid modulation of response to electrical stimulation of preoptic area or median eminence

Immunoreactive luteinizing hormone releasing factor in pituitary stalk blood from female rats: sex steroid modulation of response to electrical stimulation of preoptic area or median eminence. Sherwood, Nancy M.; Chiappa, Sharon A.; Fink, G. (Dep. Hum. Anat., Univ. Oxford, Oxford, Engl.). J. Endocrinol., 70(3), 501-11 (English) 1976. CODEN: JOENAK. DOCUMENT TYPE: Journal CA Section: 2 (Hormone Pharmacology) Ovariectomy of female rats on the morning of diestrus reduced the responsiveness at proestrus of LH-releasing factor (I) [9034-40-6] secretion to elec. stimulation of the preoptic area, but estradiol benzoate [50-50-0] or testosterone propionate [57-85-2] treatment immediately after ovariectomy augmented the response. 5.alpha.-Dihydrotestosterone monobenzoate [1057-07-4] treatment did not augment the response. Progesterone [57-83-0] did not facilitate preoptic responsiveness and, when given to rats ovariectomized at 12. 1057-07-4 and 57-85-2 which are cas registry numbers of chemicals are mentioned.00 hr of proestrus, reduced the I response at 18.00 hr on the same day. Stimulation of the median eminence increased I release to a greater extent than stimulation of the preoptic area. The facilitatory action of estradiol was less marked with the median eminence than with preoptic stimulation. ICI 46474 [10540-29-1] at 17.00 hr of diestrus did not reduce preoptic responsiveness on the morning of the next day, suggesting that it does not act as an antiestrogen at the preoptic area level. .

Comparison of the biological effects of tamoxifen and a new antiestrogen (LY 117018) on the immature rat uterus

Comparison of the biological effects of tamoxifen and a new antiestrogen (LY 117018) on the immature rat uterus. Wakeling, A. E.; O'Connor, K. M.; Newboult, E. (Biosci. Dep., ICI PLC, Macclesfield/Cheshire SK10 4TG, UK). J. Endocrinol., 99(3), 447-53 (English) 1983. CODEN: JOENAK. ISSN: 0022-0795. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) The uterotropic and antiuterotropic activities of tamoxifen [10540-29-1] and LY 117018 (I) [63676-25-5] in the immature rat uterus were evaluated. LY 117018 administered alone was less uterotropic (estrogenic) than tamoxifen. At high doses, when administered concurrently with estradiol [50-28-2], LY 117018 was more antiuterotropic (antiestrogenic) than tamoxifen. When uterine growth was maximally stimulated by prior treatment with estradiol, tamoxifen and LY 117018 were equally effective in reducing uterine wt. However, when uterine growth was induced with a dose of estradiol producing an estrogenic effect equiv. to that of tamoxifen (but less than that produced by LY 117018), LY 117018 was more effective than tamoxifen in reversing the uterotropic effect of estradiol. In animals pretreated with LY 117018, a further increase in uterine wt. occurred on treatment with tamoxifen. The increase in uterine wt. after tamoxifen was progressively reversed by increasing doses of LY 117018. The hypothesis that the antiestrogens tamoxifen and LY 117018 may act by different mechanisms, based on the apparent failure by LY 117018 to antagonize the uterotropic action of tamoxifen, is not supported by these studies.