Differential regulation of insulin-like growth factor binding protein-1 and -2 by insulin in the baboon (Papio anubis) endometrium.
BACKGROUND
The purpose of this study was to examine the effect of insulin on expression and synthesis of IGFBP-1 and IGFBP-2 in the baboon endometrium in vitro.


METHODS
Baboon endometrial explants collected from cycling, ovariectomized, steroid-treated, simulated-pregnant and pregnant animals were cultured for 48 h in the presence or absence of insulin, with or without estradiol, progesterone and hCG.


RESULTS
Insulin clearly inhibited IGFBP-1 production and mRNA expression in a time- and dose-dependent manner, whereas IGFBP-2 synthesis was not significantly affected. The inhibitory effects of insulin on IGFBP-1 were more evident in explants of non-pregnant tissue or tissue away from the implantation site. In the absence of insulin, synthesis of IGFBP-1 was induced in explants with low levels of de novo synthesis whereas IGFBP-2 synthesis was inhibited. This effect was potentiated by steroids and hCG in the explant cultures.


CONCLUSIONS
Insulin differentially regulates endometrial IGFBP-1 and IGFBP-2 secretion in the baboon.
Fleming
Steven D
SD
Department of Obstetrics and Gynecology (MC808), College of Medicine, University of Illinois at Chicago, Illinois 60612-9998, USA. stevenf@westgate.wh.usyd.edu.au
Fazleabas
Asgerally T
AT
Bell
Stephen C
SC
D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004717:Endometrium / Q000187:drug effects* / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000037:antagonists & inhibitors* / Q000235:genetics; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D008597:Menstrual Cycle; D010052:Ovariectomy; D010215:Papio; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D013256:Steroids / Q000494:pharmacology
D006063:Chorionic Gonadotropin; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D012333:RNA, Messenger; D013256:Steroids; D011374:Progesterone; D004958:Estradiol