Expression of the insulin-like growth factor and insulin systems in the luteinizing macaque ovarian follicle.
OBJECTIVE
To determine intrafollicular hormone levels and characterize the mRNA expression of the insulin-like growth factor (IGF) receptors, IGF binding proteins (IGFBP), and pregnancy-associated plasma protein-A (PAPP-A) in granulosa cells before and after an ovulatory hCG stimulus.


METHODS
Experimental animal study.


METHODS
Academic medical center.


METHODS
Adult rhesus macaques.


METHODS
Animals received exogenous FSH to promote the development of multiple preovulatory follicles. Follicles were aspirated before (0 hours) or 3, 6, 12, or 24 hours after an ovulatory hCG bolus.


METHODS
IGF1, IGF2, and insulin levels in follicular fluid were determined by radioimmunoassay. Messenger RNA (mRNA) levels in granulosa cells were determined by real-time reverse transcriptase-polymerase chain reaction. IGFBPs and PAPP-A in follicular fluid were determined by Western blot analysis and enzyme-linked immunosorbent assay.


RESULTS
IGF1, IGF2, and insulin in follicular fluid did not change during luteinization. IGF1R, IGFBP1, and IGFBP2 mRNAs were unchanged by hCG. IGF2R, IGFBP3, -5, and -6 and PAPP-A mRNA levels increased after hCG administration, while insulin receptor and IGFBP4 mRNA levels decreased after hCG administration. IGFBP3 and -6 and PAPP-A protein increased after hCG administration.


CONCLUSIONS
Dynamic changes in the expression of the IGFBPs and PAPP-A suggest tight regulation of IGF action during ovulation and corpus luteum formation.
Brogan
Rebecca S
RS
Department of Biology, Loyola College in Maryland, Baltimore, Maryland, USA.
Mix
Scott
S
Puttabyatappa
Muraly
M
VandeVoort
Catherine A
CA
Chaffin
Charles L
CL
D000818:Animals; D015153:Blotting, Western; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage; D015571:Follicular Fluid / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics; D034461:Luteinization / Q000187:drug effects; D008253:Macaca mulatta; D006080:Ovarian Follicle / Q000737:chemistry* / Q000187:drug effects; D010060:Ovulation / Q000187:drug effects; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D017451:Receptors, Somatomedin / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013002:Somatomedins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
D006063:Chorionic Gonadotropin; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D017451:Receptors, Somatomedin; D013002:Somatomedins; D005640:Follicle Stimulating Hormone; D011266:Pregnancy-Associated Plasma Protein-A