title: Metabolic state defines the response of rabbit ovarian cells to leptin.
abstract: Leptin is a hormone that mediates the effect of the metabolic state on several biological functions, including reproduction. Leptin affects reproductive functions via alterations in the release of hormonal regulators. However, the extent to which caloric restriction (CR) can affect the complex processes of reproduction by other mechanisms, such as altering ovarian functions via direct binding/response to leptin, is unknown. Therefore, the aim of the present study was to show basic ovarian cell functions and CR on the response of ovarian cells to leptin. Female rabbits were subjected to 50% CR restriction for 10days before ovulation. On the day of ovulation, both control and CR animals were sacrificed. Isolated granulosa cells were cultured for 2days with and without leptin (100ng/ml), and the accumulation of various markers was evaluated using immunocytochemistry; i.e., cell proliferation (PCNA and cyclin B1), apoptosis (bax), MAP/ERK1,2 kinase (MAPK), protein kinase A (PKA), and IGF-I. In addition, the release of IGF-I and estradiol (E2) by cells cultured with and without leptin (1, 10, 100, 1000, or 10,000ng/ml) was assessed by radioimmunoassay (RIA). In the granulosa cells of control animals, leptin promoted cyclin B1, MAPK, and PKA accumulation, but not that of PCNA, and reduced bax and IGF-I accumulation. These cells responded to leptin by increased IGF-I, but not E2release. In cells of CR animals, leptin increased cyclin B1 accumulation, but decreased PCNA, MAPK, and IGF-I expression. Bax and PKA were not affected. Leptin resulted in a decrease in IGF-I release. CR modulated the influence of leptin on E2release dose dependently, i.e., E2increased at 10 and decreased at 10,000ng/ml. Therefore, CR modified the influence of leptin on PCNA, E2, bax, PKA, MAPK, and IGF-I release, but it did not change the effect of leptin on cyclin B1 and IGF-I accumulation within the cells. Our data showed that leptin directly affected proliferation, apoptosis, and hormone release by ovarian cells, probably via PKA- and MAPK-dependent pathways. Furthermore, it was demonstrated that nutrition could influence reproduction by affecting the response of ovarian cells to leptin.
authors.affiliation: Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Abdel Halim
authors.initials: AH
authors.lastname: Harrath
authors.affiliation: Center for Genomic Medicine, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Olga
authors.initials: O
authors.lastname: Østrup
authors.affiliation: Department of Genetics and Reproduction, Research Institute of Animal Production, 949 59 Lužianky, Slovakia; Department of Biotechnology, University of SS. Cyril and Methodius, 917 01 Trnava, Slovakia.
authors.forename: Jan
authors.initials: J
authors.lastname: Rafay
authors.affiliation: Department of Genetics and Reproduction, Research Institute of Animal Production, 949 59 Lužianky, Slovakia.
authors.forename: Iveta
authors.initials: I
authors.lastname: Koničková Florkovičová
authors.affiliation: Department of Zoology and Anthropology, Constantine the Philosopher University, 949 74 Nitra, Slovakia.
authors.forename: Jozef
authors.initials: J
authors.lastname: Laurincik
authors.affiliation: Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia; Department of Zoology and Anthropology, Constantine the Philosopher University, 949 74 Nitra, Slovakia; Department of Genetics and Reproduction, Research Institute of Animal Production, 949 59 Lužianky, Slovakia. Electronic address: asirotkin@ukf.sk.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Sirotkin
mesh_terms: D000818:Animals; D017209:Apoptosis; D015415:Biomarkers / Q000378:metabolism; D031204:Caloric Restriction / Q000009:adverse effects*; D049109:Cell Proliferation; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006107:Granulosa Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007700:Kinetics; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D010062:Ovulation Induction; D011817:Rabbits; D011897:Random Allocation; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D015415:Biomarkers; D020738:Leptin; D011994:Recombinant Proteins; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: Apoptosis; Caloric restriction; Hormones; Leptin; Ovary; Proliferation; Rabbit