Gladys Sperling

Bone Development in the Albino Rat on a Low Manganese Diet

Summary We have not been able to demonstrate any abnormal tibia development in the albino rat raised on a diet low in manganese, provided the rat is normal at 21 days of age. In this respect the rat differs from the chick, at least in being much less sensitive to a low manganese diet. Only 2 cases of abnormal tibias have appeared in a total of 16 rats, born of females reared on a low manganese diet. Our limited data on rats from females reared on a low manganese diet suggest that the growth of the female is impaired, while that of the male is not.

Growth Retardation and Corneal Vascularization with Tyrosine and Phenylalanine in a Purified Diet

Summary The addition of 1% dl-phenylalanine and 1% l(-) tyrosine to a purified diet containing 10% casein produced growth retardation and external lesions. Phenylalanine is converted to tyrosine in the animal and so may add to the effect of the tyrosine. The addition of relatively large amounts of nicotinic acid or l(-)tryptophane will appre ciably alleviate the deleterious effects of these amino acids.

Effect of Sulfamerazine and Exercise on Life Span of Rats and Hamsters

Rats and hamsters of both sexes were divided into exercise and non-exercise groups with and without small amounts of sulfamerazine in the diet. In every case rats on exercise lived longer than their controls. The females outlived the males while hamster males lived slightly longer than females. Sulfamerazine had a significantly beneficial effect on life span of rats and apparently increased that of male hamsters. All rats fed sulfamerazine attained higher maximum weights than their controls. There was no consistent change in bone densities.

Growth of rats fed bile salts, urea and chlortetracycline.

Summary Addition of ox bile and bile salts to a purified diet produced differential effects on growth in rats. Deoxycholate produced growth depression (P<0.001) at all concentrations. Growth was reduced further by 1% urea or 100 mg/kg of chlortetracycline. Addition of urea with chlortetracycline tended to abolish growth depression produced by either alone.