Regulation of proto-oncogene expression and deoxyribonucleic acid synthesis in granulosa cells of perifused immature rat ovaries.
The present series of experiments examined the effects of follicle-stimulating hormone (FSH) and insulin (IN) on granulosa cell (GC) proto-oncogene expression and DNA synthesis. In the first study, GCs were harvested from immature rat ovaries after 15, 30, or 60 min of perifusion and DNA synthesis (3H-thymidine incorporation) and proto-oncogene mRNA levels were determined. The presence of c-myc and c-fos proteins was localized within GCs immunocytochemically. GCs of control ovaries exhibited modest levels of DNA synthesis and proto-oncogene expression. FSH/IN not only stimulated DNA synthesis but also increased c-myc, c-fos, and c-jun mRNA levels and the percentage of cells staining for c-fos and c-myc proteins. The protein kinase inhibitor, 2-aminopurine (2-AP), inhibited the FSH/IN-induced increases in c-myc and c-fos mRNA levels, the percentage of cells staining for Myc and Fos protein, and DNA and protein synthesis. The effects of 48 h of perifusion with FSH in the presence or absence of IN were also examined. These treatments were selected because after 48 h of continuous exposure to FSH alone, estradiol-17 beta (E2) secretion is enhanced and 3H-thymidine incorporation is inhibited. Conversely, FSH/IN maintains 3H-thymidine incorporation for up to 48 h of perifusion culture without stimulating E2 (Peluso et al., Endocrinology 1991; 128:191-196). After 48 h of perifusion, both FSH and FSH/IN stimulated c-fos mRNA and protein levels. However, high levels of c-jun mRNA and protein were detected only within GCs of FSH/IN-treated ovaries.(ABSTRACT TRUNCATED AT 250 WORDS)
Delidow
B C
BC
Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington 06032.
Lynch
J P
JP
White
B A
BA
Peluso
J J
JJ
D000818:Animals; D004247:DNA / Q000096:biosynthesis*; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005786:Gene Expression Regulation; D016762:Genes, fos / Q000235:genetics; D016758:Genes, jun / Q000235:genetics; D016259:Genes, myc / Q000235:genetics; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D007328:Insulin / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011519:Proto-Oncogenes / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D012333:RNA, Messenger; D004958:Estradiol; D005640:Follicle Stimulating Hormone; D004247:DNA