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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:... SUMMARYThe effects of sex steroid hormones on the responsiveness of the neural mechanism responsible for the secretion of LH-RF have been examined in the female rat. Responsiveness was determined at pro-oestrus by measuring the increments in immunoreactive LH-RF of pituitary stalk blood produced by electrical stimulation of the medial preoptic area or median eminence. Ovariectomy on the morning of dioestrus reduced the LH-RF response to preoptic stimulation while oestradiol benzoate (OB) or testosterone propionate (TP) administered immediately after ovariectomy significantly augmented the response. The facilitatory effect of TP was possibly due to its conversion to an aromatized derivative since 5α-dihydrotestosterone monobenzoate was ineffective. Progesterone did not facilitate preoptic responsiveness, and, when administered to animals ovariectomized at 12.00 h of pro-oestrus, reduced the LH-RF response at 18.00 h the same day. Stimulation of the median eminence produced a significantly greater increment in LH-RF than stimulation of the preoptic area. The facilitatory action of OB on the LH-RF response was less marked for median eminence compared with preoptic stimulation. The administration of ICI 46474 at 17.00 h of dioestrus did not reduce preoptic responsiveness on the morning of the next day, suggesting that this compound does not act as an 'antioestrogen' at the level of the preoptic area. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Endocrinology Bioscientifica

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

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Publisher
Bioscientifica
Copyright
Copyright © 1976 The Authors. All Rights Reserved.
ISSN
0022-0795
eISSN
1479-6805
DOI
10.1677/joe.0.0700501
Publisher site
See Article on Publisher Site

Abstract

SUMMARYThe effects of sex steroid hormones on the responsiveness of the neural mechanism responsible for the secretion of LH-RF have been examined in the female rat. Responsiveness was determined at pro-oestrus by measuring the increments in immunoreactive LH-RF of pituitary stalk blood produced by electrical stimulation of the medial preoptic area or median eminence. Ovariectomy on the morning of dioestrus reduced the LH-RF response to preoptic stimulation while oestradiol benzoate (OB) or testosterone propionate (TP) administered immediately after ovariectomy significantly augmented the response. The facilitatory effect of TP was possibly due to its conversion to an aromatized derivative since 5α-dihydrotestosterone monobenzoate was ineffective. Progesterone did not facilitate preoptic responsiveness, and, when administered to animals ovariectomized at 12.00 h of pro-oestrus, reduced the LH-RF response at 18.00 h the same day. Stimulation of the median eminence produced a significantly greater increment in LH-RF than stimulation of the preoptic area. The facilitatory action of OB on the LH-RF response was less marked for median eminence compared with preoptic stimulation. The administration of ICI 46474 at 17.00 h of dioestrus did not reduce preoptic responsiveness on the morning of the next day, suggesting that this compound does not act as an 'antioestrogen' at the level of the preoptic area.

Journal

Journal of Endocrinology – Bioscientifica

Published: Sep 1, 1976

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