Leptin directly controls secretory activity of human ovarian granulosa cells: possible inter-relationship with the IGF/IGFBP system.
OBJECTIVE
The aim of our in vitro studies was to understand the role of leptin and the insulin-like growth factor I/insulin-like growth factor protein (IGF/IGFBP) system in controlling human ovarian function.


METHODS
We studied the action of leptin (0, 1, 10, or 100 ng/ml) and immunoneutralization of IGF-I using specific antiserum (0.1%) on the release of progesterone (P), estradiol (E), oxytocin (OT), IGF-I, IGFBP-3, and prostaglandins F (PGF) by these cells using radioimmunoassay/immunoradiometric assay.


RESULTS
It was found that leptin stimulated the secretion of OT, IGFBP-3, and PGF. It suppressed the secretion of E and IGF-I, but not P, into the medium. The addition of antiserum against IGF-I decreased IGF-I output, increased P, OT, IGFBP-3, and PGF secretion, and had no effect on E release. Immunoneutralization of IGF-I also prevented or reversed the effects of leptin on P, E, IGF-I, IGFBP-3, PGF, but not on OT.


CONCLUSIONS
These observations (1) demonstrate that leptin directly controls the secretory activity of human ovarian cells, (2) confirm the involvement of IGF-I in the regulation of ovarian cells, and (3) suggest an inter-relationship between leptin and the IGF/IGFBP system in the control of these functions and the involvement of IGF/IGFBP system in mediating leptin action on the ovary.
Sirotkin
A V
AV
Research Institute of Animal Production, Nitra, Slovakia. sirotkin@vuzv.sk
Mlyncek
M
M
Kotwica
J
J
Makarevich
A V
AV
Florkovicová
I
I
Hetényi
L
L
D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D004958:Estradiol / Q000378:metabolism; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism*; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism; D018969:Insulin-Like Growth Factor Binding Proteins / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D020738:Leptin / Q000008:administration & dosage / Q000502:physiology*; D010121:Oxytocin / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D011460:Prostaglandins F / Q000378:metabolism
D017077:Culture Media, Conditioned; D007106:Immune Sera; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D020738:Leptin; D011460:Prostaglandins F; D011374:Progesterone; D004958:Estradiol; D010121:Oxytocin; D007334:Insulin-Like Growth Factor I