THE EFFECT OF THE HYPOFUNCTION OF THE THYROID GLAND, INDUCED BY METHYL-THIOURACIL, ON THE PHOSPHATASE ACTIVITY OF SOME ORGANS AND ON THE PROCESS OF OSSIFICATION IN THE RAT AND IN THE GUINEA-PIG

Abstract

The alkaline- and acid-phosphatase activity of the tissues was detd. biochemically, and the histo-chemical phosphatase localization was studied by a modification of the Gomori method. 1- to 3-month-old rats and 3- to 4-mo.-old guinea pigs were used with litter-mates as control animals. The daily dose of methylthiouracil (25-75 mg. for the rats and 100 mg. for the guinea pigs) was either mixed with the food, or suspended in the drinking water with 0.1% agar. The treatment lasted for 2-4 weeks. The changes observed in the phosphatase activity involved only the alkaline phosphatase, whereas the acid phosphatase was almost unaltered. Decreased activity was found in kidney and skeleton of rats and guinea pigs, increased activity in liver and thyroid gland of the rats. Histochemical examination showed that the endothelium of the blood vessels in the thyroid, adrenal and pituitary glands had become phos-phatase-positive to a greater extent than in normal glands. In the hypothyroid rats growth of the skeleton was reduced.