Blood sampling procedures influence serum calcitonin concentrations in rats

Abstract

Abstract The aim of this study was to determine whether serum calcitonin (S–CT) in rats is influenced by the method of taking blood samples. Sampling during halothane anaesthesia, after repeated administration of anaesthesia after a 14-day interval, and sampling without the use of anaesthetics (i.e. after the rats were made unconscious by stunning), resulted in different S–CT values (P≤0·001), whereas Ca2+ levels were not affected. In thyroidectomized rats, the S–CT values after stunning were not significantly different whereas those in sham-operated rats were different (P≤0·01). The possibility that anaesthesia may suppress stunning-induced changes in S–CT was explored in three other groups of rats subjected to halothane anaesthesia, stunning and stunning under halothane anaesthesia respectively. Although the S–CT level was highest after stunning and lowest in halothane-anaesthetized rats (P≤0·001), anaesthesia did not suppress the effect of stunning on S–CT. In conclusion the effect of sampling procedures must be considered in studies on the levels of S–CT in rats. Journal of Endocrinology (1994) 141, 267–270