TELEOST CAUDAL NEUROSECRETORY SYSTEM: SPERM DUCT CONTRACTION INDUCED BY UROPHYSIAL MATERIAL

Abstract

SUMMARY Extracts of the urophysis of the teleost Gillichthys mirabilis and material released from intact cells induced contraction of the Gillichthys sperm duct in vitro. Acetylcholine and 5-hydroxytryptamine also caused sperm-duct contraction, but specific blocking substances left the response to urophysial material unaltered. Adrenaline and noradrenaline inhibited the response of the sperm duct to urophysis extracts. The active factor was destroyed by trypsin, and had similar chromatographic properties to the peptidic teleost bladder-contracting factor also found in the urophysis. A role of this agent in spawning or other aspects of reproduction is suggested.