FC-13   THE INHIBITION OF HUMAN HAIR GROWTH BY ESTROGEN IN VITRO

LD Nelson, AG Messenger*, R. Karoo, MJ Thornton Dept Biomedical Sciences, University of Bradford, Bradford, UK and *Dept Dermatology, Royal Hallamshire Hospital, Sheffield, UK.

Estrogens can significantly influence the hair cycle and have been shown to inhibit hair growth in vivo in rodents. Although we have recently reported that estrogen receptors are expressed in the human hair follicle, the role of estrogens in human hair growth is still unclear. Therefore, we have used a whole follicle organ culture system to investigate the effect of both 17beta and 17alpha-estradiol on human hair growth in vitro. Individual hair follicles from non-balding scalp (n=3; mean age 49.3yrs) were microdissected out from surrounding skin and incubated individually in phenol red-free William’s E medium supplemented with L-glutamine, penicillin, streptomycin, 5mM glucose and either 10nM 17beta-estradiol, 10nM 17alpha-estradiol or the vehicle control (0.0001% alcohol) (6 follicles per group from each patient). The increase in the length of the follicles was measured sequentially with an inverted microscope fitted with an eyepiece measuring graticule over a seven day period. Follicles in each group exhibited linear growth over the seven-day period. Follicles incubated with 17alpha-estradiol grew at a similar rate to the control group. However, follicles incubated with 17beta-estradiol grew at a significantly slower rate than the control group. These results show that the biologically active estrogen, 17beta-estradiol, has a physiological effect on human hair growth in culture, which parallels the in vivo effects seen in rodents. We have previously shown that ERbeta is the receptor expressed in human hair follicles in situ and that it is expressed in the cells of the dermal papilla and follicular epithelium. Studies are in progress to further elucidate the mechanism of action of estrogens and estrogen receptors in the human hair follicle.