Daily i.p. administration of thyroxine (T4; 50 µg/100 g BW) to adult male rats for
one week doubled the thyroxinemia and induced significant augmentation of glycemia
and insulinemia. Hyperthyroxinemia was also manifested by significant elevation of
liver malic enzyme activity and by the presence of smaller fat cells. Adipocytes of
T4 treated rats displayed significantly lower density of insulin receptors, decreased
insulin stimulatory effect on glucose transport and less glucose transporter (GLUT4)
protein in plasma membranes after insulin stimulation as those of controls. These
results indicate a deleterious effect of hyperthyroxinemia on insulin controlled glucose
metabolism in fat cells.
Hyperthyroxinemia - Adipocytes - Glucose Transport - Glucose Transporter - Insulin
