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Sebum production was measured on 2 symmetrically placed areas on the flanks of rats over alternating periods of 18 and 6 hr for 4 days, by absorbing the lipid on pads of cigarette paper held in place by a specially designed harness. Castrated rats receiving testosterone produced about twice as much sebum as untreated littermate controls. Once daily application of ethanol to one flank significantly reduced sebum production, in comparison with the other flank in testosterone-treated but not in untreated rats. Daily application of 5 mg cyproterone acetate in ethanol to one flank in a third group of rats significantly reduced sebum production in comparison with that of the other flank treated with vehicle only. The effects became significant within 24 hr. It seems likely that the sebaceous glands received the topically applied materials by way of the pilo-sebaceous orifices rather than by transepidermal absorption. The results demonstrate that one action of cyproterone acetate is at the target site and suggest that the anti-androgen may be effective when applied topically. The method could prove useful in assessing the local action on sebaceous activity of topically applied substances. [ABSTRACT FROM AUTHOR]

Many hair follicles produce different types of hair in response to environmental changes or the mammals age, that are translated to the follicle by hormones. Androgens cause many changes, such as transforming vellus follicles producing insignificant hairs on the face to terminal beard ones at puberty or the reverse on the scalp. In male red deer the breeding season rise in androgens causes the annual production of a mane on the neck that is lost during the spring. Because the dermal papilla situated at the base of the hair follicle is important in determining the type of hair produced, androgens may act via the dermal papilla. Therefore, primary cell lines of dermal papilla cells from human and red deer follicles with different responses to androgens have been established. Specific saturable androgen receptors were present in all human papilla cells examined, with higher levels in cells from androgen-dependent follicles, e.g., beard than in control, non-balding scalp cells. In preliminary investigations of red deer, androgen receptors were only present in cells derived from mane follicles and were undetectable in flank or spring neck follicles. These similar results from both species support the hypothesis that androgens are acting on hair follicles via the dermal papilla. They also suggest that dermal papilla cells are potentially useful models for investigating the mechanism of androgen action because cultured cells appear to retain differences that relate to the androgen responsiveness of their parent follicle. The red deer seems particularly interesting in view of the much shorter hair-growth cycle than human scalp or beard follicles. [ABSTRACT FROM AUTHOR]

Although ATP-sensitive potassium (KATP) channel openers, e.g., minoxidil and diazoxide, can induce hair growth, their mechanisms require clarification. Improved drugs are needed clinically. but the absence of a good bioassay hampers research. KATP channels from various tissues contain subtypes of the regulatory sulfonylurea receptor, SUR, and pore-forming, K+ inward rectifier subunits, Kir6.X, giving differing sensitivities to regulators. Therefore, thein vitroeffects of established potassium channel openers and inhibitors (tolbutamide and glibenclamide), plus a novel, selective Kir6.2/SUR1 opener, NNC 55-0118, were assessed on deer hair follicle growth in serum-free median without streptomycin. Minoxidil (0.1–100μM, p<0.001), NNC 55-0118 (1 mM, p<0.01; 0.1, 10, 100μM, p<0.001), and diazoxide (10μM, p<0.01) increased growth. Tolbutamide (1 mM) inhibited growth (p<0.001) and abolished the effect of 10μM minoxidil, diazoxide and NNC 55-0118; glibenclamide (10μM) had no effect, but prevented stimulation by 10μM minoxidil. Phenol red stimulated growth (p<0.001), but channel modulator responses remained unaltered. Thus, deer follicles offer a practical, ethically advantageousin vitrobioassay that reflects clinical responsesin vivo. The results indicate direct actions of KATP channel modulators within hair follicles via two types of channels, with SUR 1 and SUR 2, probably SUR2B, sulfonylurea receptors. [ABSTRACT FROM AUTHOR]