Clinical Uses for Calciotropic Hormones 1,25-Dihydroxyvitamin D3 and Parathyroid Hormone-Related Peptide in Dermatology: A New Perspective

The 1996 study explored the clinical uses of calciotropic hormones 1,25-dihydroxyvitamin D3 and parathyroid hormone-related peptide in dermatology. The skin is not only the organ for the photosynthesis of vitamin D3, but also a target tissue for its activated form 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). This hormone is essential for the development and maintenance of a healthy skeleton. It was found to be a potent inhibitor of proliferation of epidermal cells and, with its analogs, it has been developed for the successful treatment of psoriasis. However, not all psoriasis patients respond to 1,25(OH)2D3 and its analogs, suggesting a possible defect in the regulation of levels of mRNA for the vitamin D receptor in these patients. Parathyroid hormone-related peptide is synthesized by the epidermis and is an endogenous antiproliferative factor. It was found that parathyroid hormone-related peptide agonists and 1,25(OH)2D3 inhibit in vitro and in vivo epidermal proliferation, whereas parathyroid hormone-related peptide antagonists stimulate both epidermal proliferation and hair growth in vivo. Therefore, these hormones have wide-ranging clinical applications in dermatology.