Exercise-induced prolactin release is related to anaerobiosis.

The response of plasma PRL to exercise, as performed on a bicycle ergometer under conditions below and above the anaerobic threshold, was studied in 10 normal young men. One hour of submaximal work against a workload at which blood lactic acid remained below 4 mmol/liter (anaerobic threshold) was accompanied by a slight decrease in plasma PRL levels, similar to the changes occurring under control conditions in the same subjects. However, during graded maximal ergometric exercise until exhaustion, plasma PRL rose promptly and significantly (P less than 0.05) when the anaerobic threshold was reached. These data suggest that PRL levels increase provided that the intensity of exercise is such that the anaerobic threshold is reached.