Nongenomic effects of 1alpha,25-dihydroxyvitamin D(3)

The hormonally active form of vitamin D, 1alpha,25-dihydroxyvitamin D(3), is the key molecule of the vitamin D endocrine system, which produces biological effects in about 30 target cell systems. Growing experimental evidence supports the hypothesis that these biological effects can be generated both by a signal transduction mechanism involving a nuclear receptor (nVDR) that modulates gene transcription, and via a nongenomic receptor located in the plasma membrane (mVDR), which modulates a complex signaling system involving the rapid opening of Ca(2+) channels. Some data reviewed herein also indicate that crosstalk between genomic and nongenomic pathways operates in several cell types, and suggest that the physiological role of the rapid, nongenomic actions might involve the regulation of hormone-mediated gene activation.