Effect of vitamin D3 on duodenal absorptive cell plasma membranes: freeze fracture replication study.

Vitamin D3 induced changes in the number of 5.8 nm sized randomly scattered particles on the EF faces of plasma membranes of chick duodenal absorptive cells. Their number increased as compared to those in rachitic animals. Also vitamin D3 seemed to alter the nature of the zonula occludens. These changes appear to be related to increased active absorption and passive diffusion of calcium respectively under vitamin D3 influence.