Histochemical changes in the skin following local application of cortisol or prednisolone

The prolonged daily application of adrenocortical extract or cortisone induces profound histological alterations in the skin of rats. These changes are limited to the area of treatment (Baker and Whitaker, '48; Castor and Baker, '50) and are particularly impressive in males. They include ( a) cessation in growth of hair, (b) thinning of epidermis, with reduction in size and flattening of epidermal cells, (c) thinning of the dermis with disappearance of subcutaneous fat, (d) compaction of dermal collagenous fibers, (e) injury to cellular components of the dermis, especially those in a superficial location, and ( f ) reduction in size of sebaceous glands. In addition, adrenocortical hormones by local action facilitate the spreading action of hyaluronidase (Hayes, Reed and Baker, '50), inhibit granuloma formation (Meier et al., '50; Baker and Whitaker, '50; Baker, '54), and suppress the inflammatory reaction. These studies demonstrated the remarkable capacity of adrenocortical compounds to alter normal histology of cutaneous tissues by direct action. Few attempts have been made to define more precisely the influence of adrenocortical hormones on the chemistry of cells in situ when this action is exerted locally and, thus, is not complicated by the profound metabolic alterations which these agents elicit after systemic administration. The recent refinement of histochemical technics for the localization of oxidative and hydrolytic enzymes within cells indicates that these procedures might be used effectively in combination with local treatment with adrenocortical steroids to gain information concerning the manner in which steroid hormones modify cellular chemistry. The introduction of nitro-blue tetrazolium in particular has made possible a much more precise localization of oxidative enzymes (Nachlas et al., '57). Hence, the objective of this investigation is to observe some of the cytochemical changes which occur in various types of cutaneous cells following the application of cortisol to the skin. Since little information is available concerning the local histological effects of analogs of cortisol, prednisolone (A'-dehydrohydrocortisone) was studied also.