Abstract
Summary
1) In rabbits given thyroxine or propylthiouracil, external balance studies for magnesium were performed, and Mg28 used to measure exchangeable body content of magnesium. In 8 rabbits given 2 intravenous injections of thyroxine sodium (0.3 mg/kg) no significant changes were noted in body weight, magnesium balance, or exchangeable magnesium content, although a decrease in serum magnesium concentration occurred. In another group of 8 rabbits the tissue relative activity of Mg28 was determined following 3 intravenous injections of thyroxine (1.0 mg/kg) given within 4 days. The relative activity was increased in liver, skin, appendix, and heart. 2) Eight rabbits given propylthiouracil orally showed a decrease in exchangeable body content of magnesium at end of third week. A significant decrease was found also in relative radioactivity of liver and bone. 3) The value for exchangeable body content of magnesium appears related to rate of turnover of Mg28 in bone and muscle, the 2 largest body stores of magnesium.
Mg28 was supplied by Brookhaven Nat. Lab. on allocation from U. S. Atomic Energy Comm.
Get full access to this article
View all access options for this article.