Regulation of oocyte maturation in the rainbow trout, Salmo gairdneri: role of cyclic AMP in the mechanism of action to the maturation inducing steroid (MIS), 17α-hydroxy, 20β-dihydroprogesterone.

In fish, oocyte maturation (resumption of meiosis after completion of vitellogenesis and before ovulation) is triggered by maturation inducing steroids (MIS) which generally appear to be secreted in the ovary in response to stimulation by a pituitary maturational gonadotropin. Converging data from different laboratories show that 17α-hydroxy, 20β-dihydroprogesterone (17α, 20β-OH-P) is the principal MIS in salmonids; but clear identification remains to be done in other taxonomic groups