[Liver deiodase activity in rats of different body weight and fat contents following high or low fat diet. Comparison of enzymatic deiodination with T4-clearance rate and thyroid activity in animals].
Weanling male wistar rats were fed 4 weeks a standard diet and separated into 2 groups, which received a high fat diet (50% w fat; HFD) or a low fat diet (3% w fat; LFD). These diets were fed 6-8 weeks and the animals then separated into light and heavy animals in each group. T4 deiodination in liver homogenates was investigated in all groups and compared with T4 clearance rate and thyroidal activity of these animals. The HFD-rats showed independently of weight and body fat content significantly higher liver deiodinase activity than LFD-rats. In light and heavy HFD-rats with great differences in body fat content the liver deiodinase activity was equal. T4 deiodination in liver, contrary to the T4 clearance rate, depends on fat content of diet and not of body. The thyroidal radioiodine uptake and PBI-131-values in some weight groups of HFD-rats were significantly higher than in some LFD-weight-groups, but a dependence of the thyroidal activity from fat content of diet or of body was not clearly evident. The results indicate however, that the thyroidal activity is likely not responsible for the increase of liver deiodinase activity after high fat diet. The apparent discrepancy between the results of higher liver T4 deiodination and equal or lower T4 clearance rate or equal T3 serum concentrations is discussed.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D007453:Iodide Peroxidase / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D010544:Peroxidases / Q000378:metabolism*; D051381:Rats; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects / Q000502:physiology*; D013974:Thyroxine / Q000378:metabolism*
D004041:Dietary Fats; D010544:Peroxidases; D007453:Iodide Peroxidase; D013974:Thyroxine
Leberdejodaseaktivität bei Ratten unterschiedlichen Körpergewichtes und -fettgehaltes nach Hoch- bzw. Niedrigfettdiät. Vergleich der enzymatischen Dejodierung mit det T4-Clearance-Rate und der Schilddrüsenaktivität der Tiere.