[Negative relation between sodium intake and prolactinaemia in the normal subject (author's transl)]

The different effects of sodium regimens administered over a period of five days were studied in 18 normal men, aged 21 to 27 years. As the dietary sodium increased, there was a parallel increase in osmolality, plasma volume, reabsorption of free water, and secretion of antidiuretic hormone. However, there was a decrease in plasma renin activity, plasma aldosterone and urine aldosterone. All of these parameters correlated significantly with the urinary sodium. Plasma prolactin did not appear to be influenced by low, normal or high sodium regimens; its values being 3.1 +/- 1.1, 2.9 +/- 1.7, 2.7 +/- 1.2 ng/ml respectively at 9 AM in an upright position. Once more, there does not exist any correlation between the plasma prolactin levels and the parameters mentioned above. In conclusion, variations in dietary sodium do not influence plasma prolactin levels in the normal human being.