J. N. Spuhler Continuities and Discontinuities in Anthropoid-Hominid Behavior Evolution: Bibliographical Excerpts
Human evolution theory utilizing concepts of neoteny & female sexual selection
An etiology of neuropsychological disorders such as autism and dyslexia, and the origin of left handedness.
"Androgens have a general anabolic effect. They reduce nitrogen excretion in many species. They promote growth of muscle. The uptake of glucose and glycogen synthesis in muscle is androgen-dependent. Men who have the genes for pattern baldness do not lose their head hair unless they have circulating androgens. Androgens increase sweat secretion rates. (Wagner and Hughes 1974). Carnivores in general have relatively large adrenal glands in terms of body weight; herbivores in general have thyroid glands relatively large in terms of body weight. The adrenals in adult women are about 70 percent larger relative to body weight than in adult female chimpanzees (Crile and Quiring 1940). Later studies of chimpanzees and rhesus monkeys confirm the relatively great size of the human adrenal glands (Bourne and Golarz de Bourne 1972; Bourne 1975; Graham 1970). Since there is no significant storage of androgens in the primate body, a fresh supply must be synthesized as it is used. The production rate of testosterone in nonpregnant adult human females is 0.29-0.35 mg/day and that of androstenedione 3.3-3.7 mg/day, the production of androgens by the adrenals being twice that of the ovaries (Reid, Ryan, and Benirschke 1972). Mean values of androgen excretion in the urine of normal women are 40 to 47 IU/day, or approximately two-thirds the amount excreted by males. Means of two adult female chimpanzees were 3.1 and 3.7 IU/day and those for ten adult female rhesus macaques ranged from 1.2 to 2.6 IU/day (Dorfman 1948: 501-502, 516). If we let 1 IU represent the biological activity of 0.1 mg. of adrosterone, the values in mg/kg/day are 0.7 for adult female chimpanzees and 8 for women. In a review of the literature, Graham (1970:203) noted that in chimpanzees male and female daily output of androgens was many times lower than the values obtained for man and close to values obtained for rhesus monkeys. Probably as a result of natural selection for endurance bipedal running, men and women have greater larger thyroid glands, and significantly larger adrenal glands and consequently greater hormone output than do rhesus monkeys and chimpanzees. (Spuhler, J.N. (1979) Continuities and Discontinuities in Anthropoid-Hominid Behavior Evolution: Bipedal Locomotion and Sexual Receptivity in Evolutionary Biology and Human Social Behavior. N. Chagnon & W. Irons, eds. pp. 458)