October - December 2020, Volume 16, Issue 4

Das P, Saha I, Chatterjee A, Pramanick K, Chakraborty SB, Maity A, Bhowal S, Pradhan D, Mukherjee D, Maiti BR

Participation of Phosphatidylinositol-3 Kinase Signalling in Human Chorionic Gonadotropin, Bovine Insulin (B-Insulin) and Human-Insulin-Like Growth Factor-I Induced Oocyte Maturation and Steroidogenesis in the Grey Mullet, Mugil Cephalus

Acta Endo (Buc) 2020, 16 (4): 426-436
doi: 10.4183/aeb.2020.426

Context. The grey mullet, Mugil cephalus, is an edible fish of high economic importance. Breeding biology with reference to hormonal/growth factor regulation of oocyte maturation needs to be known for its commercial production. Objective. The present study was conducted to examine the potency of maturation inducing hormones, chorionic gonadotropin (hCG), bovine-insulin, and insulin like growth factor1 (h-IGF-1) I on ovarian steroidogenesis and oocyte maturation. Design. The role of hormones and growth factors on steroidogenesis and oocyte maturation was investigated using specific inhibitors, Wortmannin for phosphatidylinositol-3 (PI3) kinase, trilostane for 3β-hydroxysteroid dehydrogenase, 1-octanol and 1-heptanol for gap junctions, actinomycin D for transcription and cycloheximide for translation of signal molecules. Methods. Actions of hormonal and growth factors were examined for steroidogenesis, by radioimmunoassay and oocyte maturation by germinal vesicle breakdown (GVBD). Specific inhibitors were used to determine the cell signaling pathways, PI3 kinase. Results. All the inhibitors attenuated the hCGinduced oocyte maturation (GVBD%), steroidogenesis including transcription, translation, gap junctions and PI3 kinase signaling. These inhibitors failed to inhibit h-IGF-I and b-insulin-induced oocyte maturation, steroidogenesis, translation and PI3 kinase signaling. Conclusion. hCG induces oocyte maturation via steroid dependent pathway involving gap junctions, transcription, translation and PI3 kinase signaling, unlike h-IGF-I and b-insulin in the mullet.

Keywords: hCG, b-insulin, IGF-I, steroidogenesis, PI3 kinase signaling, oocyte maturation.

Correspondence: B. R. Maiti PhD, University Of Calcutta, Zoology, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700019 India, E-mail: drbrm123@hotmail.com