Pituitary uptake of 125I-D-Leu6, Des-Gly N2(10) LH-RH-ethylamide in ovariectomized rats pretreated with oestradiol-17 beta.
The objective of this study was to determine if pretreatment of ovariectomized rats with oestradiol-17 beta affects the anterior pituitary uptake of 125I-D-Leu6, Des-Gly NH2(10)-LH-RH-ethylamide (125I-D-Leu6-LH-RH). Oestradiol-17 beta (0.5 microgram/0.5 ml oil) or oil was administered to ovariectomized rats at 2, 4, 8, 12, 16, 20 or 24 h before death, and at 30 min before death, 5 ng 125I-D-Leu6-LH-RH were injected intravenously. The serum LH response to analogue administration in oil-treated rats did not change over time, but that in oestradiol-treated rats was depressed for 4 h and restored 8-24 h after oestradiol treatment, with the greatest response being at 16 h. However, the pituitary (adrenal, CNS cortex and thyroid) uptake of 125I-D-Leu6-LH-RH in oestradiol-treated and control rats did not change over the 24-h time period. These data suggest that oestradiol-17 beta does not affect pituitary responsiveness to 125I-D-Leu6-LH-RH by inhibiting or facilitating the uptake of this analogue by the anterior pituitary.
D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D002369:Castration; D002540:Cerebral Cortex / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D013961:Thyroid Gland / Q000378:metabolism
D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone