Changes in plasma DHEAS circadian rhythm in elderly men

Several reports focused the attention on aging that appears to exert an influence on the temporal structure in the endocrine system of man. Considering that: a) DHEAS blood levels consistently decrease as men age and b) this hormone might be involved in the early development of atherosclerosis, aim of the present work to detect: 1) the possible existence of a circadian rhythm of DHEAS in young and elderly men, 2) eventual change in parameters of other hormonal rhythms. 11 young healthy males (28 +/- 2 yrs) and 12 elderly males (73 +/- 1 yrs) were studied over a 24-hr span during spring. They were submitted to the circadian protocol for the evaluation of DHEAS, PRL and cortisol plasma levels. A significant circadian rhythm of DHEAS plasma levels was observed in the young men (mesor micrograms/dl 273.13 +/- 38.25, amplitude 41.37 +/- 9.29, acrophase at 1351 hr). In the elderly subjects no circadian rhythm was found, but amplitude and mesor appeared statistically reduced in comparison with young people (p less than 0.005 and p less than 0.001, respectively). Confirming previous results the circadian pattern of PRL and cortisol did not change in the two groups. It is suggested that both loss of rhythmicity and low levels of blood DHEAS in elderly may be involved in aging process and considered an aspect of the endocrine temporal structure of old people.