Rapid actions of 1 alpha-25-dihydroxyvitamin D3 physiologic role

The steroid hormone, 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-[OH]2D3), has been shown to exert actions on cells within seconds. The rapidity of these effects has led to the speculation that they reflect nongenomic actions of the hormone which involve interaction with membrane receptors. Moreover, these rapid effects appear to modulate the actions of the hormone on gene transcription, suggesting that the physiologic role of the rapid actions may involve the regulation of hormone induced gene activation.