Vitamin D stimulates (Na+ + K+)-ATPase activity in chick small intestine

Vitamin D3 and 1,25-dihydroxyvitamin D3 raise (Na+ + K+)-ATPase activity (ouabain-sensitive 86Rb+ uptake) in cultured embryonic and 4-week-old chick small intestine. Vitamin D stimulation of the sodium pump, which requires genomic action of the sterol, may lead to enhanced Ca2+ extrusion via a basolateral Na+/Ca2+ exchange mechanism, and, in addition, may provide a proliferative signal in undifferentiated enterocytes.