GROWTH-PROMOTING EFFECT OF A TRANSPLANTABLE PITUITARY TUMOR IN PARAKEETS1

Publisher Website
Google Scholar
Abstract
The probable presence of growth hormone in the transplantable parakeet pituitary tumor was indicated by a positive tibia test in hypophysectomized rats. To test for a growth promoting effect in parakeets, 50 birds 2-19 days old were inoculated subcutaneously with the tumor and weighed weekly, 49 nest-mates served as controls. Fifteen of the inoculated birds survived 3 months; their average weights and those of the controls were: body weight-51.8 gms., vs 32.2 gms. for the controls; liver 2.55 gms., vs 0.57 gm.; kidneys 0.59 gm., vs 0.30 gm.; heart 0.59 gm., vs 0.43 gm.; brain 1.12 gm., vs 1.13 gm; pituitary 1.03 mg., vs 0.68 mg.; adrenals 6.0 mg., vs 3.9 mg.; thyroid 11.4 mg., vs 4.4 mg. Inoculated birds were moderately obese, their liver contained larger stores of fat and glycogen than the controls. However, sample cell counts showed that the greater size of the liver was associated with an increase in cell number as well as with a variable accumulation of fat. All inoculated birds showed the tumor-characteristic increase in one component of serum protein.