Effect of diethylstilbesterol and prolactin on the induction of follicle stimulating hormone receptors in immature and cycling rats.
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Date
1984-09
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Abstract
Induction of follicle stimulating hormone receptor in the granulosa cells of intact
immature rat ovary by diethylstilbesterol, an estrogen, has been studied.
A single injection of 4 mg of diethylstilbesterol produced 72 h later a 3-fold increase in
follicle stimulating hormone receptor concentration as monitored by [125I]-oFSH binding to
isolated cells. The newly induced receptors were kinetically indistinguishable from the preexisting
ones, as determined by Lineweaver-Burk plot of the binding data. The induced
receptors were functional as evidenced by increased ability of the granulosa cells to incorporate
[3H]-leucine into cellular proteins.
Neutralization of endogenous follicle stimulating hormone and luteinizing hormone by
administering specific antisera had no effect on the ability of diethylstilbesterol to induce
follicle stimulating hormone receptors, whereas blockade of endogenous prolactin secretion
by ergobromocryptin administration significantly inhibited (~ 30 %) the response to diethylstilbesterol;
this inhibition could be completely relieved by ovine prolactin treatment.
However, ovine prolactin at the dose tried did not by itself enhance follicle stimulating
hormone receptor level.
Administration of ergobromocryptin to adult cycling rats at noon of proestrus brought
about as measured on diestrus II, (a) a reduction of both follicle stimulating hormone (~ 30 %)
and luteinizing hormone (~ 45 %) receptor concentration in granulosa cells, (b) a drastic
reduction in the ovarian tissue estradiol with no change in tissue progesterone and
(c) reduction in the ability of isolated granulosa cells to convert testosterone to estradiol in
response to follicle stimulating hormone. Ergobromocryptin treatment affected only prolactin
and not follicle stimulating hormone or luteinizing hormone surges on the proestrus evening.
Treatment of rats with ergobromocryptin at proestrus noon followed by an injection of ovine
prolactin (1 mg) at 1700 h of the same day completely reversed the ergobromocryptin induced
reduction in ovarian tissue estradiol as well as the aromatase activity of the granulosa cells on
diestrus II, thus suggesting a role for proestrus prolactin surge in the follicular maturation
process.
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Keywords
Gonadotropins, receptor induction, prolactin, estrogen, follicle
Citation
Vidyashankar N, Moudgal N R. Effect of diethylstilbesterol and prolactin on the induction of follicle stimulating hormone receptors in immature and cycling rats. Journal of Biosciences. 1984 Sept; 6(3): 263-276.