The action of 1 alpha,25-dihydroxyvitamin D3 on rat small intestine: changes in translatable mRNA species.

The time course of changes in translatable mRNA from small intestinal mucosa was studied in vitamin D-deficient rats following an intrajugular dose of 1,25-dihydroxyvitamin D3. L-[35S]Methionine-labeled translation products were analyzed by high-resolution one- and two-dimensional electrophoresis. Changes were detected in two distinct proteins, Mr 14,000/pI 6.24 (Band I), and Mr 5,200/pI 4.86 (Band II). These increased to maxima of 1-2% each of the total in vitro-synthesized protein at 12 h after dosing. This represented a 3- and 10-fold increase, respectively, over control values. The time course of these changes suggests that regulation of the levels of the mRNAs coding for these proteins is not involved in the initial (6 h) peak of 1,25-dihydroxyvitamin D3-stimulated intestinal calcium transport in the rat.