Intermediary metabolism in a lizard, Calotes versicolor: role of thyroid hormones.

In Calotes versicolor, thyroidectomy did not alter the blood glucose level, lactate dehydrogenase (LDH liver and heart), acid phosphatase (Ac.Pase liver and kidney), and alkaline phosphatase (Alk.Pase liver and kidney) activities; significantly decreased the activities of glucose-6-phosphatase (G-6-Pase liver and kidney), glutamic oxaloacetic transaminase (GOT liver and heart), glutamic pyruvic transaminase (GPT liver), and urea concentration (liver and kidney); and increased liver cholesterol when compared to sham-operated controls. Administration of L-thyroxine (L-T4) or triiodo-L-thyronine (L-T3) to thyroidectomized lizards significantly stimulated the activities of G-6-Pase, Ac.Pase, GOT and GPT, concentration of glucose and urea, and decreased the cholesterol level. While the activities of all the enzymes studied and cholesterol level remain unchanged, glucose and urea levels decreased and increased, respectively, in thyroidectomized animals treated with actinomycin D. Chloramphenicol treatment did not affect any of the parameters studied. Simultaneous injections of actinomycin D or chloramphenicol with L-T4 prevented the hormone-stimulated activities of Ac.Pase, GOT, and GPT while the activities of LDH, G-6-Pase, Alk.Pase, glucose, urea, and cholesterol levels remain unchanged.