Seasonal expression and distribution of kisspeptin1 (kiss1) in the ovary and testis of freshwater catfish, Clarias batrachus: A putative role in steroidogenesis

Kisspeptin stimulates final oocyte maturation in the catfish, Clarias batrachus: an in vitro approach

“…Kiss agonist (KP-10) and its receptors antagonist (p234) were provided by Prof. R.P Millar, Department of Immunology, University of Pretoria, South Africa. Details of KP-10 and p234 are described elsewhere (Millar & Newton, 2013;Singh et al, 2021aSingh et al, , 2021b. Streptomycin sulphate Kisspeptin stimulates final oocyte maturation in the catfish, Clarias batrachus: an in vitro approach…”

“…Thereafter, ovaries were cut into small fragments with approximately 50 follicles and were placed in medium199 supplemented with 0.2% NaHCO3, penicillin 100IU/ml, streptomycin 100µg/ml and 40µg/ml gentamycin and pre-incubated for 3hr under humidified atmosphere wi th 95% air and 5% CO2 at pH 7.4 at 25°C. Then after, the culture medium was replaced with fresh medium containing various doses of KP-10 and p234 (0.0, 0.5, 5, 25 and 50 nM/ml), separately, for 24hr under similar condition (see Singh et al, 2021aSingh et al, , 2021b. Concurrently, the ovarian tissue fragments with around 50 follicles were incubated in medium199 without agonist and antagonist to use it as controls.…”

“…The entire experiments were repeated three times. The in vitro protocol to study the effect of various drugs/hormones has been well established in the laboratory of author Singh, et al, 2021aSingh, et al, , 2021bSingh nee Priyadarshini & Lal, 2018;Yadav & Lal, 2019).…”

“…The existence of kiss/kiss1r transcripts has also been identified in the brain of several fish species establishing their role of regulation of gonadotropin release hormone (GnRH) and thereby, gonadotropins (luteinizing hormone-LH, follicle stimulating hormone-FSH) (Filby et al, 2008;Gopurappilly et al, 2013;Parhar et al, 2004;Selvaraj et al, 2012). The kiss and kiss1r mRNA as well as immunoreactive kiss have also been detected in peripheral tissues including gonads of some fishes (Bakshi & Rai, 2019;Saha et al, 2016;Selvaraj et al, 2010;Shahi et al, 2017;Singh et al, 2021a;Tovar Bohórquez et al, 2017). Hitherto, the studies on their role in regulation of reproductive activities at gonad level are very rare.…”

“…Hitherto, the studies on their role in regulation of reproductive activities at gonad level are very rare. Recently, the authors have demonstrated the local effect of kiss using kiss antagonist (p234) and agonist (KP-10) both in vivo and in vitro which suggest the pro-gonadal role of kiss in catfish (Singh et al, 2021a(Singh et al, , 2021b. The KP-10 used in the study is a mammalian kiss homologue decapeptide is an endogenous ligand of kiss receptor (kiss1r/gpr54) while p234 is a ten amino acid kiss receptor (kiss1r/gpr54) antagonist which binds directly to kiss-10 binding sites and suppresses the release of GnRH.…”