ABILITY TO CULTURE DERMAL PAPILLA CELLS FROM RED DEER (CERVUS-ELAPHUS) HAIR-FOLLICLES WITH DIFFERING HORMONAL RESPONSES IN-VIVO OFFERS A NEW MODEL FOR STUDYING THE CONTROL OF HAIR FOLLICLE BIOLOGY

Red deer stags annually grow two distinct seasonal coats, a winter coa t and a summer coat; in addition, they produce a mane during the breed ing season when plasma testosterone levels are high, which is replaced by the short neck hairs of the summer coat when testosterone levels a re low. As two very different hair types are produced from the same fo llicle under hormonal regulation, they offer an interesting model for studying the effects of hormones, particularly androgens, on mammalian hair growth. Since the dermal papilla of the hair follicle has a regu latory function and is probably the site of androgen action, we have i nvestigated whether cells from the dermal papilla can be readily cultu red from various types of red deer follicles; as the follicular connec tive tissue sheath may regenerate a new papilla in vivo, this was also examined. Individual dermal papillae and lower portions of the connec tive tissue sheath were microdissected from mane and flank follicles o f red deer stags during the winter breeding season and from the summer coat during the nonbreeding season. Primary cultures were established from isolated dermal papillae, connective tissue sheath and dermal ex plants, subcultured and reestablished after freezing. Deer dermal papi lla cells resembled sheep cells; they displayed a polygonal shape and irregular organisation, but did not form aggregates in contrast to hum an and rat vibrissa cells. Connective tissue sheath cell morphology wa s intermediate between that of dermal papilla cells and dermal fibrobl asts. However, all three cell types derived during the breeding season grew at a much faster rate than the same cells derived during the non breeding season. Therefore, primary cell lines can be fairly readily d erived from deer hair follicles. Since the red deer stag offers both a ndrogen-dependent neck (mane) and control flank follicles in the breed ing season, plus control nonbreeding season neck follicles, this means that stag follicular cells, particularly the dermal papilla cells, ap pear to offer a unique novel model system for the study of the hormona l regulation of hair growth. (C) 1996 Wiley-Liss, Inc.