ABSTRACT
Dehydroepiandrosterone and its sulfate (DHEA/S) has been attracting attention of scientists for more than four decades due to a number of features by which it differs from other naturally occurring steroids present in humans: as a sulfate it is the most abundant circulating steroid, the concentrations of which are of one or two orders of magnitude higher than those of cortisol. Though it is a typical adrenal steroid, its diurnal rhythm and regulation is not paralleled by that of cortisol. There is no feedback action of DHEA/S on the pituitary or the hypothalamus (Wolf and Kirschbaum, 1999). In contrast to most hormonal steroids the major portion of DHEA is secreted by adrenals in a form of sulfate. In spite of numerous biological effects displayed by DHEA/S at various levels, neither specific receptors for this steroid, nor its competition for other hormonal receptors have been found so far. Besides adrenals and gonads, DHEA/S is synthesized by various neural cells including brain. Brain structures are also its targets. The actions of DHEA/S as neurosteroids are discussed in other chapters in this volume. The typical characteristics of DHEA/S, however, is its decline with age in both sexes, hand in hand with degenerative changes typical for ageing, as muscular weakness, hypertension, osteoporosis, diabetes, susceptibility to infection with an over-all impairment of immune function. The beneficial effects ascribed to DHEA, many of which can be explained by its immunoprotective or antiglucocorticoid effects (Kalimi et al., 1994), rendered this steroid a hot candidate for replacement therapy of seniors. A complex study on 280 subjects above 60 years to whom DHEA was given perorally for one year has been reported recently by Baulieu’s group (Baulieu et al., 2000).
