Do hormones determine our fate

: The hormonal system is a communication system between cells and organs. Hence it is not surprising that it influences almost all physiological functions and, at least partially, our behaviour and fate. The sexual phenotype is determined by the sex hormones. Normally, the phenotype is in accordance with gonadal and genetic sex, but occasionally, as a consequence of enzymatic defects in the biosynthesis of sex hormones or of androgen resistance, gonadal and genetic sex are in discordance with the phenotype, the latter determining generally the civil sex and the sex of rearing. Whereas the gender role is generally determined by the sex of rearing and the phenotype, itself under hormonal influence, homo- and transsexuality constitute notorious exceptions to this rule. Although several authors consider homo- and transsexuality to be the consequence of an impairment in androgenic impregnation in the perinatal period, there are at present no convincing arguments for an hormonal origin for either homo- or transsexuality, although such a possibility can't be excluded either. Besides their role in psychosexual behaviour, sex hormones play also a role in our life expectancy. Indeed, although maximal life expectancy of man is genetically determined, a major determinant of individual life expectancy is cardiovascular pathology. The latter is partly responsible for the difference in life expectancy between men and women, cardiovascular mortality increasing rapidly at menopause and being halved by oestrogen replacement therapy. Also atherogenesis as such is, to a large extend, under hormonal control. Indeed insulin resistance and hyperinsulinism, which develop as a corollary of the aging process, is an important cause of atherosclerosis as well as of hypertension. Other hormones also play an important role in our behaviour. We can mention here the role of the thyroid hormones in the physical and mental development of children as well as in the regression of the intellectual functions in hypothyroidism; the role of growth (and sex) hormones in the clinical symptomatology of aging; the memory enhancing effects of the antidiuretic hormone; the role of growth factors (as well as of sex hormones) in tumorigenesis; the role of corticoids (and sex hormones) in the modulation of immunological processes etc. In brief, hormones influence all aspects of our life.