The effect of thyroid hormones on the lipid composition of rat plasma and erythrocyte membranes
Digiorgio, V.M.; Cafagna, F.; Ruggiero, F.M.
Bollettino della Societa Italiana di Biologia Sperimentale 64(11): 979-984
1988
ISSN/ISBN: 0037-8771 PMID: 3245915 Document Number: 305922
The effect of thyroid hormones on cholesterol. The effect of thyroid hormones on cholesterol and phospholipid levels in plasma and in erythrocyte membranes was investigated. It was found that both plasma free and esterified cholesterol are decreased by about 30% in hyperthyroid rats and increased by about 60% in PTU-treated rats. Plasmas phospholipid concentration increased in thyrotoxic rats and decreases in hypothyroid rats by the same amount (45%). In erythrocyte membranes both cholesterol and phospholipids increase in T3-treated rats and decrease in hypothyroid rats. These findings suggest that the rate of cholesterol transfer from plasma to erythrocytes could depend on, among other factors, the circulating thyroid hormone level, i.e., it increases in hyperthyroid rats but is inhibited in the PTU-treated ones. In this way, by the concomitant increase or decrease of phospholipids, it is possible to avoid an alteration of the cholesterol/phospholipid molar ratio in the red cells, thus preventing their abnormal function.