Expression of insulin-like growth factor-II (IGF-II) messenger ribonucleic acid (mRNA), but not IGF-I mRNA, in human preovulatory granulosa cells.
Increasing evidence suggests that insulin-like growth factors (IGFs) play an important role as intra-ovarian regulators in several mammalian species. Recently, we and others have reported the presence of both IGF-I and IGF-II in human follicular fluid. The source of these follicular IGFs, however, has not been determined. In this study, we have evaluated the possibility that human ovarian granulosa cells are a production site of IGFs in vivo. We used cDNA probes to analyse directly IGF-I and IGF-II gene expression at the level of mRNA content in granulosa cells from preovulatory follicles of women undergoing either gamete intra-Fallopian transfer or in-vitro fertilization. Samples of granulosa cell RNA enriched for polyadenylated RNA [poly(A)+RNA] were hybridized with probes for human IGF-I, human IGF-II and human actin (as a control). Transfer blot analysis revealed that the enriched poly(A)+RNA of human granulosa cells from preovulatory follicles contained no detectable IGF-I mRNA. In contrast, three species of IGF-II mRNA of approximately 6.1, 4.9 and 2.1 kb were detected. These data suggest that IGF-II mRNA, but not IGF-I mRNA, is expressed in human granulosa cells collected immediately before ovulation. Our results support the concept that human ovarian IGF-II is produced locally and may function in an autocrine or paracrine fashion in the human ovary in vivo.
Geisthovel
F
F
Department of Obstetrics and Gynecology, University of California, Irvine 92668.
Moretti-Rojas
I
I
Asch
R H
RH
Rojas
F J
FJ
D000818:Animals; D001345:Autoradiography; D015342:DNA Probes; D005260:Female; D015870:Gene Expression; D006107:Granulosa Cells / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D010761:Phosphorus Radioisotopes; D011061:Poly A / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D013002:Somatomedins / Q000235:genetics*
D015342:DNA Probes; D010761:Phosphorus Radioisotopes; D012333:RNA, Messenger; D013002:Somatomedins; D011061:Poly A; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II