STIMULATION OF GONADAL AND GERM-CELL DEVELOPMENT IN LARVAL AND JUVENILE CARP (CYPRINUS-CARPIO L) BY HOMOLOGOUS PITUITARY EXTRACT

The data presented show that in larval carp, gonadal size has increase d distinctly after treatment with homologous pituitary extract (PE). M oreover, the precocious onset of primordial germ cell proliferation an d of sex differentiation into male and female gonads was induced. Body weight of treated and control specimens did not differ significantly from each other throughout the experiment. Treatment of juvenile carp with homologous PE led also to an increase in gonadal size without con comitant increase in body weight. Induction of precocious spermatogene sis was observed too. GTH-levels in control and PE-treated carp were m onitored by means of a homologous radioimmunoassay, showing that in PE -treated carp the GTH-level was distinctly elevated. The possible role of pituitary hormones in larval and juvenile gonadal development is d iscussed.