Lyochromes in the kidney. With a note on the quantitative estimation of lyochromes

Abstract

The distr. of the lyochromes in the kidneys of frogs and rats was studied by intravital microscopy. 2 types of lyochromes were found (a) a yellowish-green fluorescent pigment in the lumina and in the epithelial cells of the proximal tubules of active urinary units; these pigments are excreted and partly reabsorbed in the proximal tubules; (b) a yellowish fluorescent pigment distributed in granules in the epithelial cells of all proximal tubules whether belonging to active or inactive units. Lacto-flavin injected into animals was eliminated in the glomeruli, concentrated and partly reabsorbed in the proximal tubules and concentrated further in the lower parts of the urinary tract. Its behaviour was similar to that of fluorescein. The yellowish fluorescent lyochromes fixed in granules in the proximal tubules showed some similarity with acriflavin. Frogs kept without any food for several mos. excreted lyochromes continuously in the urine and showed abundant yellowish fluorescent material in the epithelium of the proximal tubules. Rats deprived of lactoflavin in their diet excreted lyochromes in smaller amts. than normally fed rats and frogs. In such rats lyochrome granules were still present in the epithelium of the proximal tubules, but in smaller amts. than in normally fed rats. The chemical and physico-chemical methods used for the quantitative estimation of lyochromes in plant and animal tissues were discussed and the errors involved in them pointed out. The figures obtained by these methods were probably much too low. The biological estimation of the lyochrome content was considered the most satisfactory method.