Integumentary effects of prolactin in the lower vertebrates

Abstract

Prolactin was first known as a stimulator of mammary secretion. It has since been found to induce secretion in the sebaceous glands of the mammal as well. It likewise stimulates secretory activity in the avian cropsac and in the mucous glands of fishes and of amphibians when thyroid hormone is also present. Prolactin has mitogenetic effects on a variety of structures including the amphibian stratum corneum and induces growth of the tail fin in larval anurans and in both larval and adult newts. Prolactin causes the regression of cornified tubercles in the skin of the newt yetsynergizes with androgen in the presence of the thyroid hormone to induce the formation of keratinized nuptial pads. A similar synergism between prolactin and steroidal hormones produces avian incubation patches. There is indication that prolactin may facilitate the growth of hair in mammals but detailed information is lacking. Effects on pigmentation are attributed to prolactin in two fishes. © 1975 American Society of Zoologists.