Publication Date

Fall 10-12-1979


The endocrine system, coordinated with the central nervous system, is an important mediator of the genetic-environmental interactions which influence the development of human phenotypes. For this reason, endocrine parameters provide an important source of information for anthropological studies. This research focuses on the role of the endocrine system in normal human variability, with emphasis on the steroid hormones, which affect numerous aspects of mammalian morphology, physiology and behavior. Preceding the discussion of original research is an extensive literature review on hormonal variation in each of three areas: 1) sex and inter-individual variation, with emphasis on behavior; 2) variation with age, and 3) variability among human populations. Some general hypotheses are offered concerning endocrine-environment interactions and possible genetically-determined hormonal profiles which might influence one's mental and physical state. In addition to the literature review, original research is presented in two areas: 1) steroids and aging, and 2) androgen correlates of female behavior.

Subjects were 150 primarily Caucasian male and female volunteers aged 20 to 87 from Albuquerque, New Mexico. All were healthy, active and on no hormonal therapy or other medication. Serum androstenedione (A) and testosterone (T) were assayed by radioimmunoassay; percent free testosterone was determined by equilibrium dialysis, and free testosterone concentration (FTC) was derived from the product of serum T and percent free steroid. Testosterone-binding globulin (TeBG) was determined by saturation analysis. Subjects were also inter­viewed regarding age, occupational status and other activities.

Regression analyses of steroid levels versus age were done separately for each sex. In females, A decreased dramatically, but TeBG showed no significant change with age. T and FTC declined slightly from age 20 to 50, tending to rise thereafter. In males, A declined from age 20, leveling off after age 60; T showed no significant change with age, and FTC decreased steadily from the twenties, associated with an increase in TeBG. A is an adrenal and gonadal androgen produced in greater quantities by females, and studies suggest a biological role for A separate from that of T, which is secreted in greater quantities by males. The validity of the concept of 11adrenopause 11 is considered, and the possible relation­ship of decreased adrenal androgens to age-related physiological and behavioral changes in both sexes is hypothesized. Sex differences in the pattern of change with age in these steroids were observed which might be related to male-female differences in age-associated degenerative disease rates.

Analysis of variance of steroid levels versus occupational status was per­formed on the female data. A, T and FTC correlated positively with occupation; in general, those in the category "Professional, managerial, technical II exhibited higher A, T and FTC than those in the categories "Clerical" and "Housewife." In addition, A, T and FTC correlated different! y with a rating measuring the com­plexity of the relationship of an employee to DATA, PEOPLE and THINGS. A and FTC correlated significantly with PEOPLE, and T correlated significantly with THINGS A was also associated with a variable measuring the amount of responsibility the subject assumes.

Although correlations tell nothing of cause-and-effect, it is concluded that the observed associations most Iikely reflect genetic-environment interact ion, wherein hormones influence personality characteristics predisposing an individual to certain activities, which in tum inhibit or stimulate steroid secretion. Most importantly, the observed correlations suggest that androgens are not merely "male hormones" but may be important for normal female behavior as well.

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First Committee Member (Chair)

Peter Workman

Second Committee Member

Henry Harpending

Third Committee Member

Stan Rhine

Fourth Committee Member

William Mitchell

Fifth Committee Member

Lambert H. Koopmans