Due to the continued high prevalence of low levels of vitamin D in the blood of people in the vast majority of regions of the world, the discovery of the variety of extraskeletal effects of vitamin D, the issue of maintaining adequate intake of vitamin D in the body remains extremely urgent, especially in individuals at risk of severe deficiency. Few studies have been conducted on the peculiarities of vitamin D metabolism in pathological conditions such as hypercortisolism and acromegaly. However, vitamin D deficiency in such patients may occur more often and be more pronounced than in the general population. For the treatment of most of these diseases, it is now recommended to use standard prophylactic and therapeutic doses of vitamin D for the general population, which may not meet the therapeutic goals specific to each disease. This review provides information about the metabolism of vitamin D under normal conditions, and also reviews literature data concerning the study of the possible connection and mutual influence of these endocrinopathies and the metabolism of vitamin D.