Weiss, J. -M. and Xia, Y. -X. and Polack, S. and Diedrich, K. and Ortmann, Olaf (2006) Short-term effects of IGF-I and estradiol on LH secretion from female rat gonadotrophs. GROWTH HORMONE & IGF RESEARCH, 16 (5-6). pp. 357-364. ISSN 1096-6374,
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Objective: Growth factors and ovarian steroids modulate LH-secretion from pituitary gonadotrophs. Our previous studies demonstrated that long-term IGF-I treatment enhanced LH-secretion from female rat pituitary cells and estradiol facilitated this effect. The effects of estradiol on LH secretion are time-dependent. Short-term treatment inhibited, long-term treatment enhanced GnRH-induced LH-secretion in serum-containing medium. Here we tested the short-term actions of IGF-I and its interaction with estradiol and whether IGF-I is a prerequisite for the negative effect of short-term estradiol treatment in female rat pituitary cells. Design: Pituitary cells were incubated with a series of increasing concentrations of estradiol (1 pM, 10 pM, 50 pM, 100 pM, 500 pM, 1 nM, 10 nM and 100 nM) for 4 h, IGF-I (10 pM, 100 pM, 1 nM and 10 nM) for 4 h and 14 h and their combinations for 4 h in serum-free medium, and then stimulated with 1 nM GnRH during the last 3 h of incubation. To clarify the role of IGF-I, cells were incubated simultaneously with estradiol, IGF-I and antibody against IGF-I. LH was measured by radioimmunoassay. Results: Short-term IGF-I treatment did not modify basal or GnRH-induced LH-secretion. Short-term treatment with estradiol did not affect basal or GnRH-induced LH-secretion in serum-free medium. The addition of 100 pM IGF-I to serum-free medium established the negative effect of estradiol short-term treatment on GnRH-induced LH-secretion. The addition of IGF-I antibody fully abolished the negative effect of estradiol. Conclusions: In conclusion, effects of IGF-I on LH-secretion in female rat pituitary cells require long-term treatment. The negative effect of estradiol short-term treatment on GnRH-induced LH-secretion is dependent on serum-containing medium or the addition of 100 pM IGF-I to serum-free medium. (c) 2006 Elsevier Ltd. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GROWTH-FACTOR-I; LUTEINIZING-HORMONE SECRETION; ANTERIOR-PITUITARY-CELLS; BINDING-PROTEINS; GENE-EXPRESSION; RELATIVE AMOUNTS; ESTROUS-CYCLE; FACTOR SYSTEM; INSULIN; SERUM; IGF-I; estradiol; LH; GnRH; pituitary; short-term effects |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Frauenheilkunde und Geburtshilfe (Schwerpunkt Frauenheilkunde) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 25 Jan 2021 08:03 |
| Last Modified: | 25 Jan 2021 08:03 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33926 |
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