1988 Volume 51 Issue 4 Pages 199-206
This study examined acute effects of hot water immersion on the secretion of human alpha-atrial natriuretic peptide (ANP), cyclic GMP (c-GMP), arginine vasopressin (AVP), plasma renin activity (PRA) and aldosterone in venous blood. Ten healthy subjects (mean age: 20.5yr.) underwent hot water immersion (IM) of 40°C for ten minutes by quiet sitting, which simulates usual bathing among Japanese. ANP rose from 19 to 34pg/ml with the peaked value at ten minutes of IM (p<0.001), and remained signifcantly elevated during 10 to 30 minutes after IM. Then they qradually returned to the pre-immersing level by 50min. c-GMP showed similar timed responeses as ANP. Between those parameters significantly positive linear correlation (p<0.001) was observed. AVP did not change immediately after IM, but tended to rise at 20 minutes after IM. PRA and aldosterone increased in rates of the changes later at 15 to 30 minutes, but less significantly as ANP. Those results suggested that the secretion of ANP by water immersion was enhanced by thermal stimuli in spite of short duration of central hypervolemia by water immersion. Suppressing effects of water immersion on AVP and renin-aldosterone system were small. On the contrary, hot water stimuli exerted rebounding increases on them. c-GMP seemed to be one of the indicative factors relating to the change of ANP.
