Serum and saliva sex hormone levels in !Kung San men

Abstract

Serum concentrations of testosterone (Tser), 5 alpha-dihydrotestosterone (DHT), estradiol 17 beta (E2), and free testosterone in saliva (Tsal) were determined by means of the radioimmunoassay method in 114 !Kung San men living in the Bushmanland district of Namibia. The healthy men (mean age 26.4 years) were asked about their dietary habits over the last two months and their acute alcohol intake during the 24 hours preceding the blood and saliva sampling. Although the sex hormone status of the !Kung lies within the range of normal men reported for Caucasoid samples, both Tser and Tsal exhibit relatively low concentrations in comparison to the great majority of published mean values. On the other hand, comparatively high DHT levels point to an elevated 5 alpha-reduction of testosterone to DHT in our sample. Estradiol concentrations show no deviation from normal values reported elsewhere for healthy young men. Different dietary habits of the !Kung lead to significant differences in their sex hormone status: both levels of Tsal and the androgen ratio Tsal/Tser decrease with increasing supplement of the traditional hunter-gatherer diet with domestic and Western food products. The amount of alcohol consumed during the day before the blood and saliva sampling shows a significant effect on the DHT metabolism, and the shorter the time after drinking, the greater decrease of DHT and DHT/E2 can be observed.

Anthropology of human reproduction: The male factor

“…The San define a birth as live only if the child receives a name, which means that it must have lived for about 3 days at least. 20 In the morning hours, blood and saliva samples were collected from our probands in order to determine the following sex hormone concentrations by radioimmunoassay: 21 Total testosterone in the serum (T ser ); Free salivary testosterone (T sal ), the biologically active fraction of total testosterone; 5␣-dihydrotestosterone (DHT); and Estradiol (E 2 ).…”

“…As was expected in males under 40 years of age, we were unable to detect a significant decrease in androgen levels with increasing age of our probands. 21 Testosterone is the most important 6,25 In addition to the effects of gametogenesis, testosterone plays an important role in hair growth, 26 bone metabolism, 27 muscle mass and distribution, 28 and secondary sexual characteristics. 29 In the serum, testosterone is mainly bound to sex-hormone-binding globulin; only free testosterone molecules, about 2% of total testosterone, are biologically active.…”

Androgen Levels and Body Size Are Associated with Directional as Well as Fluctuating Asymmetry Patterns in Adult !Kung San and Kavango Males from Northern Namibia

“…This so called Viennese Kalahari project was carried out in close cooperation with the Department of Human Biology of the University of Hamburg. Detailed description of this project was presented in numerous publications [54][55][56][57][58][59][60][61][62]. Altogether, 250 subjects were enrolled in the present study.…”

“…The intra-and interassay coefficients of variation were within the usual limits reported (Tser 6.6% and 11.4%; DHT 10% and 12.9%; Tsal 7.1%). Hormonal analyses have been published in previous studies [54,55].…”

“…Nevertheless, most studies focusing on asymmetry patterns have been conducted in developed countries such as the United States or European countries. Furthermore only few studies focused on androgen levels among adult males following a hunter gatherer subsistence [47][48][49][50][51][52][53][54][55]. Therefore, in the present study, for the first time, the relationship between asymmetry patterns and androgen levels during adulthood was tested among male !Kung San foragers and Kavango horticultural pastoralists.…”