Expression Kinetics of Vitellogenin Gene in Estradiol-17β Induced <i>Catla catla</i>

Abstract

Vitellogenin (Vtg) is the yolk precursor protein in fish and is synthesized in the liver under estradiol-17β (E2) stimulation. In all oviparous animals, Vtg is synthesized as a response to endogenous estrogen in females in the breeding season. It also could be induced exogenously by E2 in males and juveniles. In the current study the inducibility of Vtg gene in Indian major carp, Catla catla was tested. A semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay was developed for kinetic study of Vtg mRNA level in C. catla after primary and secondary inductions by E2. It was found that the level of Vtg-specific mRNA was highest following 12 h post treatment in primary induction, and after 1 d post treatment in secondary induction. There was a sharp decrease in Vtg mRNA level on day one and day two in primary and secondary induction, respectively. Thus the ‘memory effect’ of vitellogenin induction by E2 in catla could not be confirmed.