Estrogens in Plasma of the Hagfish,Myxine glutinosa (Cyclostomata)

Concentrations of estrogens in the plasma of Myxine glutinosa were measured in an attempt to determine whether different stages of reproduction are connected with certain levels of steroid concentration. After extraction with diethylether and column chromatography on Sephadex LH-20, the plasma was radioimmunoassayed for estrogens. Samples were subdivided into 9 groups according to the gonadal conditions of the animals. There appears to be a positive correlation in females between plasma estrogen concentration and egg size (taken as an indication of reproductive stage). After ovulation the level of plasma estrogens fell appreciably. Estrogen levels of most of the samples from male animals were also determined.