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 follicle and epidermis mitotic activity. In rats, it caused a generalized hair growth wave without affecting the regrowth cycle. Hydrocortisone slightly inhibited early cycle stages, while cortisone injections significantly suppressed regrowth, especially in undercoat hair. The study suggests differences in blood supply might explain the varied responses between outercoat and undercoat hairs.