Androgen Control of the Pilosebaceous Gland

Abstract

Numerous studies have established the dependence of sebaceous gland development on androgen. Sebum production levels in castrated men are considerably lower than in intact men (Strauss and Pochi 1963). However, the administration of testosterone to castrated males, children or postmenopausal women, in whom sebaceous secretion is normally low, results in a significant increase in sebaceous gland activity. The sebaceous gland is thus an androgen target organ (Pochi and Strauss 1974). Evidence that the sebaceous glands in women are less than maximally stimulated was suggested by studies in which the oral administration of methyltestosterone in daily doses of 100–200 mg sometimes produced a histologically detectable increase in sebaceous gland size (Strauss et al. 1962). In women with hirsutism, sebum excretion rate is higher when hirsutism is associated with acne, but there are many patients with extensive hirsutism in whom neither acne nor seborrhoea are observed. The problem regarding hair growth is more complex. The body surface of an infant, with the exception of the scalp and eyebrows, is covered with fine, soft, light-coloured hair; this is the vellus hair. Later in life, the hair at certain specific sites is replaced with longer, thicker and coloured terminal hair. This transformation of the vellus hair into the terminal hair appears to be governed by androgens. The amount of androgen necessary to effect this change depends upon a number of factors, Among them the race, sex and age of the individual and the site of the hair follicle on the body. Thus the transformation of pubic and axillary hair takes place under the influence of a small amount of androgen produced by normal women at the time of puberty.