Newly discovered activities for calcitriol (1,25-dihydroxyvitamin D 3 ): Implications for future pharmacological use

Abstract

Recent studies have yielded new insights into the critical importance of adequate vitamin D 3 intake and metabolism. Investigations of the actions of 1,25-dihydroxyvitamin D 3 (calcitriol) on novel target tissues has revealed that this hormone has functions other than its recognized action in regulating blood calcium and phosphate levels. Reports have characterized calcitriol receptors and activities in organs and tissues as diverse as pancreas, skeletal and heart muscle, blood cells, brain, skin, pituitary, parathyroid, kidney, bone and intestine. These studies suggest functions for calcitriol as varied as the regulation of insulin and prolactin secretion, muscle contractility, immune cell metabolism, melanin synthesis and differentiation of blood cells. This information may ultimately help us to understand the etiologies of several kinds of organ dysfunction and lead to the development of tissue-specific agents for new therapies.