title: Recent advances in meiotic maturation and ovulation: comparing mammals and pisces.
abstract: Meiotic maturation is a complex process that involves resumption of meiosis in response to preovulatory luteinizing hormone (LH) surge just before ovulation. High levels of cAMP in oocytes maintain meiotic arrest at diplotene of prophase I in mammals and pisces. In mammals, the process by which LH induces recommencement of meiosis involves breakdown of oocyte-somatic cells communication, which is followed by a drop in intracellular cAMP levels that in turn causes exit from meiotic arrest. Maturation promoting factor (MPF) then accomplishes progression of oocytes to reach first metaphase followed by second metaphase after reinitiating meiosis. Pisces require precise completion of oocyte growth involving vitellogenesis before the entry of meiotic maturation. Then, both mammalian and fish oocytes enters resumption of meiosis involving germinal vesicle breakdown, chromosome condensation, assembly of meiotic spindle, and formation of first polar body. However, this process in pisces is regulated by three major mediators, LH, 17alpha,20beta-dihydroxy progesterone and MPF which are unique. The molecular mechanisms of meiotic maturation and ovulation by comparing mammalian and piscine research have been dealt in this review.
authors.affiliation: Department of Animal Sciences, School of Life Sciences-Centre for Advanced Studies, University of Hyderabad, PO Central University, Hyderabad 500 046, Andhra Pradesh, India. bsksl@uohyd.ernet.in
authors.forename: Balasubramanian
authors.initials: B
authors.lastname: Senthilkumaran
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D054758:A Kinase Anchor Proteins / Q000502:physiology; D000818:Animals; D003349:Cortisone Reductase / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D005399:Fishes / Q000502:physiology*; D006801:Humans; D008322:Mammals / Q000502:physiology*; D016200:Maturation-Promoting Factor / Q000502:physiology; D008540:Meiosis / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology; D010060:Ovulation / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism; D013256:Steroids / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D054758:A Kinase Anchor Proteins; D010750:Phosphoproteins; D013256:Steroids; D014157:Transcription Factors; D000098682:Steroidogenic Acute Regulatory Protein; D000242:Cyclic AMP; D015096:3-Hydroxysteroid Dehydrogenases; D003349:Cortisone Reductase; D013254:Steroid 17-alpha-Hydroxylase; D016200:Maturation-Promoting Factor