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Human granulosa contain messenger ribonucleic acids encoding insulin-like growth factor-binding proteins (IGFBPs) and
L C Giudice1, A A Milki, D A Milkowski
1Department of Gynecology and Obstetrics, Stanford University Medical Center, California 94305-5317.
Objective:
To determine if luteinizing human granulosa cells contain messenger ribonucleic acid (mRNAs) encoding insulin-like growth factor-binding protein (IGFBPs) and if cultured granulosa secrete IGFBPs into conditioned medium (CM).
Design:
Northern analysis, using IGFBP-specific complementary deoxyribonucleic acid probes, was used to detect granulosa-derived IGFBP mRNAs. Western ligand blot analysis of CM was used to detect IGFBPs secreted by granulosa cultures with and without human chorionic gonadotropin (hCG).
Setting:
Granulosa cells were obtained from the In Vitro Fertilization (IVF) Program at Stanford University, a private teaching institution.
Patients, Participants:
Patients undergoing IVF for tubal disease.
Interventions:
None.
Main Outcome Measures:
Transcripts of IGFBP mRNA and IGFBPs secreted into CM were detected by autoradiography of Northern and Western ligand blots, respectively.
Results:
Transcripts of IGFBP-3, IGFBP-2, and IGFBP-1 mRNA were detected in human luteinizing granulosa. Cultured granulosa secreted IGFBPs with molecular weights corresponding to IGFBP-3, IGFBP-2, and IGFBP-1, and the latter two IGFBPs increased with 10 ng/mL hCG. A 24 kd IGFBP was noted, which may be newly characterized IGFBP-4.
Conclusions:
These data show that luteinizing human granulosa cells express mRNAs encoding three IGFBPs, secrete IGFBPs into culture medium, and that production of at least two of the IGFBPs is hCG-dependent, further supporting a role for the IGF system in human folliculogenesis.