Leptin directly controls proliferation, apoptosis and secretory activity of cultured chicken ovarian cells.
The aim of our in-vitro experiments was to examine, whether leptin can directly control functions of avian ovarian cells and to outline potential intracellular mediators of its effects. Granulosa cells or fragments of ovarian follicular wall were cultured with leptin (0, 1, 10 or 100 ng/mL medium). The expression of peptides involved in apoptosis (TdT, bax, its binding protein, bcl-2, ASK-1 and p53), cell cycle-related peptides (PCNA and cyclin B1), release of hormones (progesterone, testosterone, estradiol, arginine-vasotocin), as well as the expression of protein kinases (PKA, MAPK/ERK1,2 and CDK/p34) in the ovarian cells were examined by using immunocytochemistry, TUNEL, SDS-PAGE-Western immunoblotting, EIA and RIA. It was found that leptin inhibited expression of all markers of cytoplasmic apoptosis (bax, ASK-1 and p53), stimulated expression of anti-apoptotic peptide bcl-2, but did not affect nuclear DNA fragmentation (TdT). Furthermore, leptin inhibited expression of PCNA (marker of S-phase of mitosis), but not of cyclin B1 (marker of G phase of cell cycle). Moreover, it promoted release of progesterone and estradiol, suppressed release of testosterone, but did not affect arginine-vasotocin. Finally, leptin inhibited expression of MAPK/ERK1,2 and CDK/p34 and stimulated expression of PKA. The present observations demonstrate that leptin can directly control basic chicken ovarian functions - inhibit cytoplasmic apoptosis and proliferation (S-phase, but not G-phases of mitosis), regulate secretory activity (release of steroids, but not nonapeptide hormone) and expression of MAPK, PKA and CDC2, which might be potential intracellular mediators of leptin action.
Sirotkin
A V
AV
Research Institute of Animal Production, Slovak Centre of Agricultural Studies, Hlohovská 2, 949 92 Nitra, Slovakia. sirotkin@scpv.sk
Grossmann
R
R
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002645:Chickens; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D051358:Cyclin-Dependent Kinase 4 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000378:metabolism; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D020738:Leptin / Q000378:metabolism* / Q000494:pharmacology; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D006080:Ovarian Follicle / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D011374:Progesterone / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013739:Testosterone / Q000378:metabolism; D046509:Tissue Culture Techniques; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014668:Vasotocin / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D019926:Cyclin B; D056744:Cyclin B1; D020738:Leptin; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D017868:Cyclic AMP-Dependent Protein Kinases; D051358:Cyclin-Dependent Kinase 4; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048848:MAP Kinase Kinase Kinase 5; D014668:Vasotocin