ON THE INFLUENCE OF (ŒSTRIN INJECTIONS ON THE BALANCE BETWEEN THE PREHYPOPHYSEAL GONADOTROPIC HORMONES OF THE MALE RAT

The injection of impure œstrin (from urine of the pregnant mare) into the adult normal male rat causes the luteinizing faculty of the prehypophysis, as revealed by subcutaneous administration to the infantile female rat, to be diminished whereas the œstrogenic faculty remains unaltered or is even sometimes increased. The administration of male œstrin‐prehypophysis does not always cause luteinization, although with the same quantities of male control prehypophysis a coefficient of luteinization of Q lut = 0·95 may be obtained. When greater quantities of œstrin‐prehypophysis are given luteinization also occurs, but the coefficient of luteinization decreases as the number of the injections is increased (down to Q lut = 0·12). The effect of œstrin injections on the prehypophysis of the adult normal male rat is interpreted as being due to a change in the balance between the œstrogenic and the luteinizing gonadotropic hormones, the quantity of the luteinizing factor being diminished. The prehypophyseal weight is greater in œstrin‐injected adult male rats than in normal ones. These results make it highly probable that the prehypophysis of the uncastrated adult male rat injected with œstrin behaves differently from the prehypophysis of the œstrin‐injected castrated male. Œstrin injections produced in most cases a partial disturbance of spermatogenesis. Possibly autolytic substances emanating from the seminal tubules with disturbed spermatogenesis interfered in the gonadotropic balance of the prehypophysis.