Plasma estradiol-17β and gonadotropin during ovulation in rainbow trout (Salmo gairdneri R.)

Abstract

A radioimmunoassay (RIA) for estradiol-17P (E2-17p) with a chromatogra- phic step has been tested on rainbow trout plasma. Overloading and dilution tests gave satisfactory results. Intracardiac injection of E2-17! (10 fL9/ kg) in July gave a peak in the first 30 min after injection ; return to the basic level occurred within the next 24 hrs. Using RIA, trout-gonadotropin (t-GTH) and E2-17J3 were followed in trout plasma during the very last stages of the reproductive cycle. Oocyte maturity was determined simultaneously.