Response of Plasma Prolactin to Changes in Ambient Temperature and Humidity in Man

Abstract

The present study examined the relationship between plasma PRL and ambient temperature and relative humidity (RH) in man. Six normal men sat in an environmental room on four occasions. On each occasion, a thermoneutral control period at 27 C dry bulb (db)/16 C wet bulb (wb; 32% RH) was followed by a 90-min exposure to 27 C db/16 C wb, 13 C db/ 9 C wb, 45 C db/26 C wb, or 27 C db/26 C wb (92% RH) and a recovery period. Blood was drawn at 30-min intervals. Plasma PRL rose 53% (P < 0.05) in the heat and fell 37% (P † and K^† levels did not change, except in the cold where serum K† rose 0.6 meq/liter (P < 0.01). These data suggest an association between ambient temperature and plasma PRL in man which is not associated with changes in water and electrolyte status.