Expression of leptin and its receptor in the murine ovary: possible role in the regulation of oocyte maturation.
Leptin is a product of the ob gene that is produced primarily by adipose tissue. Leptin and its receptors are found within the ovary, but it is unclear what function this hormone has in the ovary. Using immunohistochemistry, we determined that leptin is found in most cell types in the murine ovary, with the highest staining levels observed in the oocyte. Leptin receptor was also expressed in all of the main ovarian cell types, with the thecal cell layer exhibiting the highest staining levels. Leptin administration did not affect spontaneous or induced maturation of either isolated denuded oocytes or cumulus-oocyte complexes, but it did significantly increase the rate of meiotic resumption in preovulatory follicle-enclosed oocytes (P < 0.01). Measurements of cAMP within oocytes cultured with leptin showed that this enhanced ability to resume meiosis does not occur via activation of phosphodiesterase 3B and subsequent cAMP reduction. These results provide evidence that leptin affects oocyte maturation when the oocyte is cultured within its normal follicular environment. It is suggested that leptin may induce the production of another factor, possibly from thecal cells, that directly or indirectly acts on the oocyte to initiate germinal vesicle breakdown in this species.
Ryan
Natalie K
NK
Reproductive Medicine Unit, Department of Obstetrics and Gynaecology, The University of Adelaide, The Queen Elizabeth Hospital, Woodville Road, Woodville, South Australia 5011, Australia.
Woodhouse
Carole M
CM
Van der Hoek
Kylie H
KH
Gilchrist
Robert B
RB
Armstrong
David T
DT
Norman
Robert J
RJ
D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000502:physiology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D005260:Female; D007150:Immunohistochemistry; D020738:Leptin / Q000096:biosynthesis* / Q000494:pharmacology / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000254:growth & development* / Q000378:metabolism; D006080:Ovarian Follicle / Q000502:physiology; D010053:Ovary / Q000378:metabolism* / Q000502:physiology*; D011247:Pregnancy; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D013256:Steroids / Q000096:biosynthesis; D013799:Theca Cells / Q000378:metabolism
D002352:Carrier Proteins; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D013256:Steroids; C515447:leptin receptor, mouse; D000242:Cyclic AMP