EXTRACTS OF UROPHYSIS OF CRUCIAN CARP INDUCING CONTRACTION EFFECT ON THE INTESTINES OF MANDARIN FISH IN VITRO

Extracts of urophysis of crucian carp (Carussius auratus L.)induced rhythmic contractions of the intestines of mandarin fish (Siniperca chuatsiB.)in vitro. The contractfion effect of the extracts showed a high degree of sensitivityand good reproducibility. The experiments was found to be dose-dependent. Repro-ducible responses were obtained with as little as 0.05 of a urophysis/ml in fluid bath.It was suggested that the isolated mandarin fish intestines could be used to substitutefor trout rectum in order to provide the bioassay method for the estimation of urote-nsin Ⅱ. Acetylcholine Was used for a laboratory reference standard.