Effects of L-thyroxine on plasma biochemistry in broiler chicks (Gallus gallus)

The effect of a single intraperitoneal injection of a low dose (1 mu g/g) and a high dose (4 mu /g) of thyroxine (T 4) were investigated with time on plasma metabolites in broiler (Hubbard) chicks. Plasma total proteins, albumin fraction, glucose and triglyceride levels were decreased significantly in both experimental groups. The plasma cholesterol values remained almost comparable with controls during the early stages of the experiment but after 72 hours of the experiment higher dose of T 4 resulted in a significant (p<0.01) decrease followed by significant (p<0.05) increase in the same experimental group. The plasma albumin fraction decreased significantly in animals injected with higher dose of T/sub 4/ after 24 hours and the same trend continue even after 72 hour of the experiment. Plasma uric acid values were significantly decreased in group administered with lower dose of T/sub 4/ after 12 hours of the post injection time. However in animals administered with higher dose of thyroid hormone reflected a significant increase in plasma uric acid levels after 12 hours of the experiment and its levels were significantly decreased after 48 hours. The results are discussed in the light of previous reports of thyroid hormones and their physiological implications in different vertebrate groups. (author)