Abstract
The silver nitrate technique for the histochemical demonstration of ascorbic acid has been applied to the adrenals of the rat. Whole glands, fresh-frozen and frozen-dried sections were treated with the silver reagent. Diffusibility of ascorbic acid in the adrenal tissue was studied in tissue disc preparations and with "section chromatography". The following conclusions were derived:
1) Concentrations of silver nitrate, acetic acid and alcohol in the reagent are not critical.
2) Light does not affect the results under the conditions of the present study.
3) Excess silver nitrate must be washed out before fixation in thiosulphate.
4) Ascorbic acid is in a highly diffusible form in the adrenal cortex.
5) The solvent penetrates adrenal tissue at a higher speed than silver nitrate.
6) The presence of silver granules in the zona glomerulosa and the medulla of glands immersed as a whole into the silver reagent is due to dislocation of ascorbic acid during the histochemical procedure.
7) Diffusion of ascorbic acid is reduced to the minimum by treating fresh-frozen or frozen-dried sections with the silver reagent. Silver granules are in such sections restricted to the fasciculata and reticularis.
8) Stimulation of the adrenal cortex with injections of adrenaline or ACTH cause a depletion of silver granules mainly in the lower parts of the fasciculata and the reticularis.
9) Histochemically demonstrable ascorbic acid is probably distributed evenly in the cell both in normal and in stimulated adrenals. This point requires further study.