The Effect of Adrenalectomy and Adrenocortical Hormones on the Hair Growth Cycle in the Rabbit and Rat

The study investigated the effects of cortisone and adrenalectomy on hair regrowth in rabbits and rats. Bilateral adrenalectomy did not affect hair regrowth rate or coat quality in rabbits but altered mitotic activity in hair follicles and epidermis. In rats, adrenalectomy caused a generalized hair growth wave but did not affect the regrowth cycle. Hydrocortisone slightly inhibited early hair regrowth, while cortisone injections significantly suppressed it, particularly affecting undercoat hair more than outercoat hair. The study suggests that differences in blood supply might explain the varied responses between hair types.