European Journal of Biotechnology and Bioscience

The comparative studiesrnon thyroid hormones triiodothyrinine (T3) ,thyroxin (T4),pituitary thyrotropinrn(TSH) and sex steroids (testosterone and estrogen) level has been estimated inrnfour fresh water carp fishes, Labeo rohita, Catla catla, Cirrhana mrigala, Labeornfimbriatus collected from wild irrespective of sex before breeding periodrnfrom a local aquatic body. The thyroxin (T4) is the predominant hormone than triiodothyrininern(T3) in all the carps studied with highest level in the carp fish, Cirrhanarnmrigala. The pituitary TSH level is uniformly same in all the carp fishes.rnAmongst the sex steroid hormones, testosterone is predominant hormone withrnhigher levels in the carp fish, Catla catla than other three carprnfishes. The estrogen level is less compared to testosterone in all the fishesrnwith higher level in Catla catla compared to other carp fishes. Althoughrnall the carp fishes exhibited normal levels of the hormones studied, thernpredominant hormones are thyroxin (T4) and testosterone indicating that all thernfishes belong to males.