The involvement of leptin, MAP kinase- and CDC2 kinase-dependent intracellular mechanisms in the control of horormonone release by chicicken ovarianarianarianarianarian granuranuranuranulosa cells

Abstract

The aim of our in-vitro experiments was to examine, whether the metabolic hormone leptin, mitogen activated kinase (MAPK) and cyclin-dependent protein kinase (CDK) can control secretory functions of avian ovarian cells and to outline, whether MAPK and CDK can be potential intracellular mediators of leptin effects. Granulosa cells isolated from chicken ovaries were cultured with leptin (0, 1, 10, 100, 1.000 or 10.000 ng/ml medium) in the presence or absence of MAPK blocker PD98059 and CDK blocker olomoucine. The release of hormones (arginine-vasotocin, AVT, estradiol, E2 and progesterone, P4 ) was evaluated by EIA and RIA. It was found that leptin inhibited release of AVT but stimulated E2 and P4 output. MAPK blocker, when given alone, reduced AVT release, but promoted secretion of E2 and P4 . Moreover, it prevented leptin action on P4 , inverted leptin effect on E2 , but did not affect a pattern of leptin action on AVT. CDK blocker, when given alone, inhibited AVT and E2 release, but stimulated P4 output. Moreover, CDK blocker prevented or inverted leptin action on the release of all hormones studied. Present observations demonstrate that leptin, MAPK and CDK are involved in the control of chicken ovarian secretory activity (release of steroid and nonapeptide hormone), and leptin can affect ovarian hormones through MAPK- and CDK-dependent intracellular mechanisms.