metribolone and Alopecia

We attempted to establish a coculture model of human dermal papilla cells (DPCs) from androgenetic alopecia (AGA) and keratinocytes (KCs) to study the pathomechanism of AGA. Since expression of mRNA for the androgen receptor (AR) decreased during subcultivation of DPCs in vitro, we transiently transfected the AR expression vector into the DPCs and cocultured them with KCs. In this coculture, androgen inhibited the growth of KCs by 50%, indicating that the DPCs produce diffusible growth suppressive factors into the medium in an androgen-dependent manner. Since recently increasing evidence has shown the importance of transforming growth factor-beta1 (TGF-beta1) in hair growth, we further examined the concentration of TGF-beta1 in this coculture medium after androgen treatment by ELISA assays. The results showed that androgen treatment increased the secretion of TGF-beta1 into the conditioned medium. Moreover, neutralizing anti-TGF-beta1 antibody reversed the inhibition of KC proliferation. Thus, we suggest that androgen-inducible TGF-beta1 derived from DPCs mediates hair growth suppression in AGA.

Topics: Alopecia; Androgens; Antibodies; Cell Division; Cells, Cultured; Coculture Techniques; Culture Media, Conditioned; Enzyme-Linked Immunosorbent Assay; Humans; Keratinocytes; Metribolone; Osmolar Concentration; Receptors, Androgen; Skin; Transfection; Transforming Growth Factor beta; Transforming Growth Factor beta1

We attempted establishing an in vitro coculture system by using human dermal papilla cells (DPCs) from androgenetic alopecia (AGA) and keratinocytes (KCs) to explore the role of androgens in hair growth regulation. Androgen showed no significant effect on the growth of KCs when they were cocultured with DPCs from AGA. Because the expressions of mRNA of androgen receptor (AR) decreased during subcultivation of DPCs in vitro, we transiently transfected the AR expression vector into the DPCs and cocultured them with KCs. In this modified coculture, androgen significantly suppressed the growth of KCs by approximately 50%, indicating that overexpression of AR can restore the responsiveness of the DPCs to androgen in vivo. We found that androgen stimulated the expression of TGF-beta1 mRNA in the cocultured DPCs. ELISA assays demonstrated that androgen treatment increased the secretion of both total and active TGF-beta1 in the conditioned medium. Moreover, the neutralizing anti-TGF-beta1 antibody reversed the androgen-elicited growth inhibition of KCs in a dose-dependent manner. These findings suggest that androgen-inducible TGF-beta1 derived from DPCs of AGA is involved in epithelial cell growth suppression in our coculture system, providing the clue to understand the paradoxical effects of androgens for human hair growth.

Topics: Alopecia; Cell Division; Coculture Techniques; Dermis; Hair; Hair Follicle; Humans; Keratinocytes; Metribolone; Models, Biological; Receptors, Androgen; RNA, Messenger; Testosterone Congeners; Transfection; Transforming Growth Factor beta; Transforming Growth Factor beta1; Up-Regulation

The physiopathological role of androgen binding proteins in male pattern baldness (MPB) has been studied by using tritiated dihydrotestosterone (DHT) and methyltrienolone (R 1881) as ligands. DHT binding in bald scalp from subjects suffering from MPB is high (53 +/- 12 fmol/mg protein) in cytosol obtained from bald areas, being undetectable in hairy areas from the same subject. Since methyltrienolone does not bind in bald scalp cytosol, there must be no specific DHT receptor in this material. Several kinetic and molecular parameters of DHT binding in bald scalp cytosol and serum were similar in both samples. Only the association rate constant (k+1) was significantly higher in serum (8.8 X 10(6) M-1 min-1) than in cytosol (3.08 X 10(6) M-1 min-1). DHT binding in serum as well as the evaluation of plasma contamination in the skin samples (by nephelometric analysis) strongly suggests that DHT binding in skin cytosol is merely due to the presence of contaminating SHBG but it does not explain the lack of DHT binding in non bald areas. Thus, the possibility arises of there being a specific mechanism for the uptake of the plasmatic testosterone SHBG-complex taking place only in the hypertrophic sebaceous gland as well as the existence of active T metabolites other than DHT, probably 3 beta-androstanediol.

Topics: Alopecia; Blood Proteins; Centrifugation, Density Gradient; Concanavalin A; Cytosol; Dihydrotestosterone; Estrenes; Humans; Kinetics; Male; Metribolone; Radioligand Assay; Receptors, Androgen; Sebaceous Glands; Sepharose; Testosterone