When physiological doses of tritiated vitamin D3 are administered to rachitic chicks, the small intestine accumulates a large portion of the dose. The subcellular distribution of the 3H-vitamin D3 within the intestinal mucosa cells shows the radioactivity to be primarily associated with the nuclear fraction. The radioactivity is retained in this fraction when it is purified by sedimentation in 2 m sucrose. In vitro incubation of 3H-vitamin D3 with homogenates of vitamin D-deficient and normal chick mucosa cells indicates a selective binding of the vitamin to the nuclear fraction derived from the rachitic chicks.
ASJC Scopus subject areas
- Molecular Biology