Inhibition of Somatic Growth in Castrate Rats with Pituitary Extracts. ∗

Abstract

Male and female rats were castrated when 22-23 days old, and! intraperitoneal injections of adrenocorticotropic extracts 1 (A-C-T) were given daily beginning on the day following the operation. The growth of hair over the shaved operative areas and over the whole body was very greatly retarded in the animals given large amounts∗ of A-C-T. There was retardation and almost complete inhibition of somatic growth when a high level of A-C-T was administered.

There was a noticeable protrusion of the abdomen of the animals treated with the higher levels of A-C-T (42.0 + 42.2 units).† At autopsy the abdominal viscera of the injected animals appeared to be as large as those of the untreated spayed rats in spite of the disparity in body weight. The weights of the various organs were taken in the rats treated with 42.2 units of A-C-T, in the control spayed rats and in 23-day-old normal female rats.

There had been no inhibition in the growth of the spleen and kidney, and only a slight inhibition (?) in the growth of the liver and digestive tract of the treated rats. The heart and thyroids were considerably smaller than in the untreated spayed animals. The pre-putials were enlarged in the injected animals. The thymus was very atrophic and in some cases completely atrophied.