Evolutionary biology of prolactins and somatotropins: I. Electrophoretic comparison of tetrapod prolactins

Abstract

Proteins of the adenohypophyses of representatives of all four classes of tetrapods were separated by polyacrylamide disc gel electrophoresis and tested for prolactin activity by the local intradermal pigeon crop sac (PCS) test. Prolactin activity was associated with prominent proteins in the glands of all of the species studied. In most of these, the prolactins had relatively high mobilities in the electrophoretic system used. It is suggested that electrophoretic separation and quantification of tetrapod prolactins will be of considerable value for physiological studies.