caa a22 4500 60623005X CHVBK 20210128101212.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s10695-015-0044-y doi (NATIONALLICENCE)springer-10.1007/s10695-015-0044-y Melanins as biomarkers of ovarian follicular atresia in the catfish Heteropneustes fossilis [Elektronische Daten] biochemical and histochemical characterization, seasonal variation and hormone effects [Ravi Kumar, Keerikkattil Joy] Follicular atresia is a common feature of the vertebrate ovary that occurs at different stages of folliculogenesis and ovarian regression. It has physiological significance to maintain homeostasis and control fecundity, and ensure removal of post-ovulatory follicular remnants for preparing the ovary for the next cycle. Pigments appear late in the atretic process as indigestible waste formed out of the degradation of the oocytes, follicle wall and granulocytes. In the present study, pigment accumulation was demonstrated by Schmorl's and Perls' staining methods in the atretic ovarian follicles of Heteropneustes fossilis during follicular development and regression. Melanins were characterized spectrophotometrically for the first time in fish ovary. The predominant form is eumelanin, followed by pheomelanin and alkali-soluble melanin. Melanins showed significant seasonal variations with levels low in gonad resting phase, increasing to the peak in the post-spawning phase. The concentration of melanins increased time-dependently in post-ovulated ovary after human chorionic gonadotropin treatment. In the spawning phase, in vitro incubation of ovary slices with estradiol-17β or dexamethasone for 8 or 16h decreased both eumelanin and pheomelanin levels time-dependently. The alkali-soluble melanin showed a significant decrease only in the dexamethasone group at 16h. The results show that melanin assay can be used as a biomarker of follicular atresia in fish ovary, natural or induced by environmental toxicants. Springer Science+Business Media Dordrecht, 2015 Catfish nationallicence Dexamethasone nationallicence Estradiol-17β nationallicence Follicular atresia nationallicence hCG nationallicence Melanins nationallicence Spectrophotometric assay nationallicence Kumar Ravi Department of Zoology, Centre of Advanced Study, Banaras Hindu University, 221005, Varanasi, India aut Joy Keerikkattil Department of Zoology, Centre of Advanced Study, Banaras Hindu University, 221005, Varanasi, India aut Fish Physiology and Biochemistry Springer Netherlands 41/3(2015-06-01), 761-772 0920-1742 41:3<761 2015 41 10695 https://doi.org/10.1007/s10695-015-0044-y text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10695-015-0044-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kumar Ravi Department of Zoology, Centre of Advanced Study, Banaras Hindu University, 221005, Varanasi, India aut NATIONALLICENCE 700 1- Joy Keerikkattil Department of Zoology, Centre of Advanced Study, Banaras Hindu University, 221005, Varanasi, India aut NATIONALLICENCE 773 0- Fish Physiology and Biochemistry Springer Netherlands 41/3(2015-06-01), 761-772 0920-1742 41:3<761 2015 41 10695