Effects of daytime noise load on the sleep-wake cycle and endocrine patterns in man: II. 24 hours secretion of anterior and posterior pituitary hormones and of cortisol.

The present study examines the effects of auditory stress on the plasma levels of pituitary hormones and cortisol. Each of twelve healthy male subjects participated in two experimental series; during one of them they were exposed to 85 dB(A) industrial noise from 9:00 to 21:00 h. Blood samples were taken by an indwelling venous catheter for 24 h at intervals of 20 min from 8:00 to 8:00 h. The plasma levels of ACTH, growth hormone, prolactin, oxytocin, vasopressin and cortisol were determined. In all subjects except one noise stress affected the profiles of the pituitary hormones but the responses were interindividually different. The oxytocin level was significantly elevated (p less than .01), ACTH also responded but less clearly, whereas the other hormones reacted only in individual cases. During the subsequent night sleep only PRL concentrations were elevated above the baseline plateau in several subjects. It was concluded that in humans the pituitary responses to noise stress are highly individual.