CELL-KINETICS OF ANAGEN SCALP HAIRS UNDER PHYSIOLOGICAL AND PATHOLOGICAL CONDITIONS

The cell kinetics of anagen scalp hair bulbs taken by punch biopsies f rom healthy male volunteers (n = 50) were determined at defined bulbar hair segments using microdissection and DNA flow cytometry. The highe st proliferative activity (S phase) was measured within the lower most bulbar segment (14.0%) but decreased to the Auber's segment (7.6%) an d to the isthmus segment (5.9%). The results support histoautoradiogra phic data demonstrating most of the proliferative activity in the hair bulb below the Auber's level [1]. Furthermore, cell kinetic data of d issected anagen hair bulbs segmented at Auber's level from an androgen -sensitive scalp area were studied in male pattern baldness (n = 15, H amilton IV) and hirsutism (n = 13). The results revealed a significant increase of S phase cells in male pattern baldness (8.9%) compared to healthy males (n = 10, 7.9%) as well as in hirsutism (10.2%) compared to healthy females (n = 10, 7.5%). In hirsutism the percentages of S phase cells ran parallel to the plasma levels of dehydroepiandrosteron e sulfate whereas no correlation to testosterone could be proved. Simi lar, 6 hypothyroid and 6 hyperthyroid patients were studied. In hypert hyroidism an increase of S phase values (10.3%) was found, while it de creased in hypothyroidism (6.1%). A correlation between the height of S phase and plasma triiodothyronine level was noted. Our studies demon strate that DNA flow cytometry is a suitable method for the evaluation of physiological or hormonal influences on cell cycle kinetics of hum an anagen hair bulbs in vivo.