Dynamic expression of 11β-hydroxylase during testicular development, recrudescence and after hCG induction, in vivo and in vitro in catfish, Clarias batrachus

Cytochrome P450 11 beta-hydroxylase (11 beta-h), is involved in the production of 11-hydroxytestosterone, an immediate precursor for 11-ketotestosterone (11-KT), a potent androgen in teleosts. To understand the role of 11 beta-h in gonadal development, maturation, function and recrudescence in an annually reproducing teleost, the present study was conducted using Clarias batrachus. Four forms of 11 beta-h cDNA, regular type (2.253 kb), variant I (1.290 kb), variant 2 (1.223 kb) and variant 3 (1.978 kb) were identified from the testis of catfish which expressed ubiquitously with high levels in testis. 11 beta-h transcripts were detected as early as 0 days post hatch further, stage- and sex-dependent increase in the 11 beta-h transcripts were seen during gonadal differentiation/development In addition, high expression of 11 beta-h (regular type) in pre-spawning phase was detected. Corroboratively, levels of 11-KT in serum and testicular tissue was high during pre-spawning and spawning phases, which might facilitate initiation and normal progression of spermatogenesis. The expression of 11 beta-h was high after human chorionic gonadotropin induction in vivo (all forms), and in vitro (regular type). Immunohistochemical and immunofluorescence localization showed the presence of 11 beta-h in Sertoli and interstitial/Leydig cells of the testis. These results suggest that 11 beta-h is involved in late stages of testicular development, together with the regulation of seasonal reproductive cycle in catfish. (C) 2014 Elsevier Inc. All rights reserved.