Ovarian steroids modulate content and secretion of immunoreactive gonadotropin-releasing hormone in a rabbit endometrial cell line.
Incubation of a rabbit endometrial cell line (HRE-H9 cells) with KCl (5-60 mM) for 30 min enhanced IR-GnRH secretion, with 30 and 60 mM producing the greatest stimulatory effect (280 +/- 19% and 298 +/- 49% of control group, respectively). By adding 30 mM KCl into HRE-H9 culture and increasing the incubation time to 90 min, there was a stepwise increase in IR-GnRH secretion. In the third experiment, treatment of HRE-H9 cells with estradiol (E2, 10(-9)-10(-8) M) for 48 h stimulated IR-GnRH secretion (215 +/- 17%, 168 +/- 19%, respectively), whereas P4 treatment did not produce any significant change. Treatment with E2 + P4 at all doses tested (10(-10)-10(-6) M) augmented the secretion of IR-GnRH (140 +/- 16%, 153 +/- 14%, 276 +/- 23%, 259 +/- 26%, 198 +/- 16%, respectively). Increased IR-GnRH secretion by E2 (10(-9) M) and E2 + P4 (10(-8)-10(-7) M) resulted in a reduction in cell content of IR-GnRH (p < 0.05). In conclusion, secretion of IR-GnRH by HRE-H9 cells can be induced by KCl depolarization. Treatment of HRE-H9 cells with E2 and E2 + P4 enhanced their secretion of IR-GnRH. Under such conditions, secreted IR-GnRH appears to be derived primarily from intracellular IR-GnRH pools.
Chin
M P
MP
Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens 30602.
Smith
C K
CK
Li
W I
WI
D000704:Analysis of Variance; D000818:Animals; D002460:Cell Line; D003470:Culture Media; D004717:Endometrium / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D011189:Potassium Chloride / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology*; D011817:Rabbits; D011863:Radioimmunoassay
D003470:Culture Media; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol; D011189:Potassium Chloride