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

Abstract

The active factor which induces the terrestrial (red eft) phase of Diemyctylus viridescens to enter water is prolactin. The red eft water-drive test indicates that a prolactin-like hormone is present in the hypophysis of teleostean fishes. Pituitary extracts of late spawning carp (Cyprinus carpio) and pre- or post-spawning Fundulus heteroclitus gave a positive response. Pollack (Pollachius virens) pituitary brei from pre-spawning fishes gave only a weak response, and negative results were obtained with Fundulus pituitary glands from fish at the beginning of the spawning season. Although confirmation is needed, these data suggest a possible period of depletion during the early spawning phase of the sexual cycle. The experiments also demonstrated that the pituitary of the species investigated contains a growth promoting factor and a molting hormone.