PRESENCE OF THE RED EFT WATER-DRIVE FACTOR PROLACTIN IN THE PITUITARIES OF TELEOSTS

Abstract

It has been demonstrated, by means of the red eft water-drive test, that a prolactin-like hormone is present in the hypophysis of teleostean fishes. Pituitary extracts from late spawning carp (Cyprinus carpio) and pre- or post-spawning killifish (Fundulus heteroclitus) gave a positive response in all instances. Pollack pituitary brei (Pollachius virens) from pre-spawning fishes gave only a weak response, and wholly negative results were obtained with an extract of Fundulus pituitary glands from fish taken at the beginning of the spawning season. While these data suggest a possible period of depletion during the early spawning phase of the sexual cycle, the findings require confirmation. The experiments also demonstrated that the pituitary of the three species investigated contains a growth-promoting factor and a molting hormone, presumably somatotropin and thyrotropin, respectively.