Fatty acid composition of sebum wax esters and urinary androgen level in normal human individuals

To investigate the effects of androgens on the fatty acid compositions of sebum wax esters, we examined sebum and urinary samples from 36 healthy individuals, aged from 3 to 59 years. The percentages of C16:1 straight chain components in wax esters were correlated positively with the urinary testosterone levels in both sexes, and with the urinary levels of etiocholanolone and total 17-ketosteroids (17-KS) in females. These data suggest that more active sebaceous glands in lipid production excrete sebum with a higher proportion of C16:1 straight chain fatty acid, which is considered to be purely endogenous. It appears, therefore, that the proportion of C16:1 straight chain fatty acid in sebum wax esters may indicate the sebaceous gland activity in both sexes. In comparison of the amounts of various straight and terminally branched fatty acids in sebum with urinary androgen levels, the straight even fatty acids tended to change in a positive correlation with testosterone levels, in contrast to the changes of the iso even fatty acids in both sexes and to those of the iso odd fatty acids in males. The straight odd fatty acids showed a similar change to that of the straight even fatty acids in males, while in females, there was no significant correlation between the amounts of the fatty acids and testosterone levels. Anteiso fatty acids showed no notable change correlated with testosterone levels. This result suggests that the synthesis of iso or anteiso fatty acids may be controlled by complex factors and that there may be a unique source of anteiso fatty acids in human sebaceous glands.