The Effects of Xylazine on Plasma Concentrations of Growth Hormone, Insulin-like Growth Factor-I, Glucose and Insulin in Calves.

Abstract

The purpose of the present study was to examine the responses of plasma growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels to intravenous injection of xylazine in female dairy calves. Xylazine (0.05, 0.15 and 0.30 mg/kg body wt., i.v.) injections induced a significant dose-dependent increase in plasma GH level within 30 min. After plasma GH levels reached peaks, GH concentrations began to decrease immediately and they returned to control levels 1 h after xylazine injection. Plasma IGF-I concentration tended to be suppressed by xylazine treatment. Xylazine induced a significant dose-dependent increase in plasma glucose for 3.5 to 5.5 h after the treatments. Xylazine also induced a significant decrease in plasma insulin level within 30 min after treatments. The present data suggested that xylazine stimulates GH release in cattle.