Premium
Enzyme Response to Thyrotoxicosis and Hypothyroidism in Human Liver and Muscle: Comparative Aspects *
Author(s) -
Nolte J.,
Pette D.,
Bachmaier B.,
Kiefhaber P.,
Schneider H.,
Scriba P. C.
Publication year - 1972
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1972.tb00582.x
Subject(s) - endocrinology , medicine , glucokinase , biology , phosphoglucomutase , phosphoenolpyruvate carboxykinase , dehydrogenase , malate dehydrogenase , biochemistry , enzyme , insulin
. 1. Activities of phosphoglucomutase, hexokinase, glucose‐6‐phosphate dehydrogenase, triosephosphate dehydrogenase, mitochondrial glycerophosphate dehydrogenase, hexosediphosphatase and phosphoenolpyruvate‐carboxykinase, of enzymes involved in the citric acid cycle and connected pathways, of hydroxyacyl‐CoA dehydrogenase and carnitine acetyltransferase were determined in biopsy specimens of liver and of tibialis anterior muscle from thyrotoxic and hypothyroid patients and from controls. The results are compared with data obtained from liver and red and white muscle of thyrotoxic rats and guinea pigs. 2. Concomitant with diminished glucose tolerance, the glucokinase activity is decreased in thyrotoxic human liver. The decrease of rat liver glucokinase activity as a response to administered thyroid hormones is found to be dose‐dependent. A relationship between the diminished glucose tolerance in thyrotoxicosis and the decrease of glucokinase activity is discussed. The increase of hexokinase activity (isozyme II) is the most interesting finding in thyrotoxic human muscle because of its possible significance with respect to the elevated metabolic rate. The activity of triosephosphate dehydrogenase, (NADP) malate dehydrogenase, phosphoenolpyruvate carboxykinase and carnitine acetyltransferase is markedly enhanced in human thyrotoxic liver, whereas that of phosphoglucomutase is diminished. 3. Mitochondrial glycerophosphate dehydrogenase, which is known to be markedly increased in the liver and red muscle of thyrotoxic rats, is not increased in the liver and tibialis anterior muscle of thyrotoxic patients, nor in the liver and white muscle of thyrotoxic guinea pigs. The enzyme responses to thyrotoxicosis in human liver and muscle are more similar to those of the guinea pig than of the rat.