Evidence for Thyroid Hormone Deficiency in Iron-Deficient Anemic Rats

J Beard, B Tobin, W Green

J Nutr. 1989 May;119(5):772-8.

PMID: 2498473

Abstract:

Iron-deficient anemic rats have previously been shown to have low plasma levels of thyroid hormone and a poor plasma thyroid hormone response to acute cold exposure. As an initial exploration, we examined thyroid hormone metabolism during iron deficiency in age-matched rats from three aspects: 1) plasma TSH (thyrotropin, thyroid stimulating hormone), T4 (thyroxine) and T3 (triiodothyronine) responses to graded doses of exogenous TRH (thyrotropin releasing hormone), 2) plasma T3 kinetics, and 3) rates of hepatic T3 production. Iron-deficient anemic rats had lower basal TSH values and blunted TSH responses to intravenous TRH injection at three different doses (10, 25 and 50 ng TRH/100 g body wt). Iron-deficient anemic rats also had a significant decrease in plasma T3 turnover (42 vs. 88 ng/h in controls), and significantly lower hepatic T4-5'-deiodinase activities than controls [26 vs. 44.0 ng T3/(mg protein.20 min)]. Thus, decreased rates of T3 production in iron-deficient anemic rats, as documented by turnover studies, may be related to decreased deiodinase activity and reduced peripheral formation of T3. The dampened TSH responses to TRH further facilitate or perpetuate this T3 deficiency. We propose that this abnormal thyroid state is partially responsible for impaired thermogenesis in iron-deficiency anemia.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP63088040	T3MG		63088-04-0	Price