Nitrogen Metabolism of the Normal and the Vitamin A-Deficient Rat as Affected by Thyroid Administration

Publisher Website
Google Scholar
Abstract
The nitrogen metabolism of young rats fed a purified diet containing 22% casein, with or without vitamin A and with or without administration of 100 mg desiccated thyroid per 100 gm body weight per day was observed for 30 to 38 days. The utilization of nitrogen for growth was depressed by both the vitamin A deficiency and the thyroid treatment, more severely in the females than the males, but there was no cumulative effect when the 2 conditions were present together. Instead, the use of protein by the deficient animals, as shown by increase in carcass nitrogen and by growth, was less affected by the thyroid than was that of their normal controls. Nitrogen retention during the later period of the deficiency was depressed by thyroid treatment in the fullfed and pairfed normal animals but improved in the deficient groups. There was little change in the ammonia or uric acid fraction of the urinary nitrogen in any case, but a small decrease in allantoin excretion was noted in the hyperthyroid rats which was less pronounced in the deficient groups. No increase in the vitamin A requirement resulted from this amount of thyroid treatment in either sex, but instead there may have been a reduction in the requirement of the females. No relationship is indicated therefore between total metabolism and vitamin A requirement as shown by nitrogen exchange.

This publication has 15 references indexed in Scilit: