Evidence that the insulin-like growth factor binding protein-4 protease in human ovarian follicular fluid is pregnancy associated plasma protein-A.
Ovarian insulin-like growth factor binding protein-4 (IGFBP-4) proteolysis is involved in the regulation of follicular development, but until now the identity of the responsible enzyme was unknown. In this study, we identify the IGFBP4 protease in human follicular fluid as pregnancy associated plasma protein-A (PAPP-A) based on distinctive IGFBP-4 cleavage pattern, the same protease inhibitor profile, specific inhibition and immunodepletion of IGFBP-4 protease activity with PAPP-A polyclonal antibodies, and immunorecognition by PAPP-A monoclonal antibodies in ELISA. Furthermore, PAPP-A levels in estrogen-dominant and androgen-dominant follicular fluids reflect their IGFBP-4 proteolytic activity. PAPP-A was also secreted by human granulosa cells, the reputed source of IGFBP-4 protease activity in follicular fluid. We have the molecular and biochemical tools to begin to delineate the regulation and biological function of PAPP-A in normal and dysregulated follicular development and atresia.
Conover
C A
CA
Endocrine Research Unit, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA. Conover.Cheryl@Mayo.Edu
Oxvig
C
C
Overgaard
M T
MT
Christiansen
M
M
Giudice
L C
LC
D017077:Culture Media, Conditioned; D004492:Edetic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005307:Fertilization in Vitro; D005347:Fibroblasts / Q000378:metabolism; D015571:Follicular Fluid / Q000201:enzymology*; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000378:metabolism; D008666:Metalloendopeptidases / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism; D010618:Phenanthrolines / Q000494:pharmacology; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis* / Q000378:metabolism
D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D018974:Insulin-Like Growth Factor Binding Protein 4; D010618:Phenanthrolines; D004492:Edetic Acid; D008666:Metalloendopeptidases; D011266:Pregnancy-Associated Plasma Protein-A; C025205:1,10-phenanthroline