1,25-dihydroxyvitamin D3 and the regulation of macrophage function.

Vitamin D3 deficient (D-) mice show a depressed inflammatory response and both inflammatory peritoneal macrophages and bone marrow polymorphonuclear leukocytes of D- mice exhibit a decreased spontaneous migration under agarose. The impaired phagocytic response of peritoneal macrophages from D- mice can be corrected by incubation with 1,25-dihydroxyvitamin D3 and is not affected by interaction with other vitamin D3 metabolites. Transfer of mice from the D- to the D+ state results in correction of both the inflammatory and the phagocytic response. Intactness of phagocyte function is thus directly dependent on vitamin D3 metabolism.