The effect of acute or chronic administration of prolactin on renal function in feral chickens

The role of the hormone prolactin in avian osmoregulation has not been clearly defined. The increases in plasma prolactin concentrations which have been demonstrated in previous studies in response to osmotic stress are strongly suggestive of a role for prolactin in avian osmoregulation. The present study investigated the effects of either acute or chronic administration of ovine prolactin on plasma electrolytes and renal function in the feral chicken. The effect of acute administration of prolactin depended on the dose of prolactin used. All plasma concentrations of prolactin achieved by the infusions were greater than reported values for endogenous prolactin. Acute infusion of prolactin at the lower dose increased the fractional excretion of sodium and chloride significantly, whereas the higher dose of prolactin had no effect. However, chronic administration of ovine prolactin had no significant effects on plasma electrolytes and renal function. It is possible that the role of prolactin in avian osmoregulation is a combination of its effects on the kidneys and also on extrarenal tissues such as the intestine and nasal salt glands (where present).