BLOOD-SAMPLING PROCEDURES INFLUENCE SERUM CALCITONIN CONCENTRATIONS IN RATS

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 anaest hesia after a 14-day interval, and sampling without the use of anaesth etics (i.e. after the rats were made unconscious by stunning), resulte d in different S-CT values (P less than or equal to 0.01), 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 less than or equal to 0.01). The possi bility that anaesthesia may suppress stunning-induced changes in S-CT was explored in three other groups of rats subjected to halothane anae sthesia, stunning and stunning under halothane anaesthesia respectivel y. Although the S-CT level was highest after stunning and lowest in ha lothane anaesthetized rats (P less than or equal to 0.001), anaesthesi a did not suppress the effect of stunning on S-CT. In conclusion the e ffect of sampling procedures must be considered in studies on the leve ls of S-CT in rats.