A Fluorescence Microscopic Observation of Vitamin D_3 Distribution in the Tissue of the Rat.

It has been reported that the oral administration of vitamin D_2 dissolved in olive oil followed by formaldehyde fixation reveals vitamin D_2 as yellowish spots under the fluorescence microscope. In order to compare this technic with the electron microscopic investigation of the effect of vitamin D_3 on the alkaline- and adenosine- triphosphatase activity in the intestine, the followinf modifications were tried: (i) repeated intramuscular injections of vitamin D_3 solution instead of a single oral administraion of vitamin D_2 dissolved in oil, and (ii) glutaraldehyde fixation instead of paraformaldehyde fixation. The studies were performed in normal adult rats. Intramuscular injevtions of aqueous solution of vitamin D_3 resulted in the same distribution of fluorescent spots as those obtained by the oral administration. Repeated injection of fluorescent spots as those obtained by the oral administration. Repeated injections (10,000 I. U. to 130,000 I. U.) slightly enhanced the fluorescence but revealed the same localization as that with a single dose. The fluorescence with glutaraldehyde was similar to that seen with paraformaldehyde. The interval between the last injection and the examination appeared to be the most important determinant in the histological localization of the fluorescence. ...