Lix. Quantitative Histochemical Distri13ijtion of Oxidized and Iwduce:i) Pyridise Sucleotides in the Rat Adresal Akd the Influence of Acth*

As part of a continuing study of the quantitative distribution of biochemically significant substances and activities in the separate zones of the adrenal gland in various functional states, the present report deals with pyridine nucleotidrs. In addition to other coenzyme functions, the pyridine nucleotides are involved in the hydroxylation of steroids in the adrenal (1, 2). Total osidized and total reduced pyridine nucleotides were determined fluorometrically in microtomc sections of rat adrenal, and data wrre related to protein-nitrogen content. The values from different adrenal zones were subjcctcd to a four-way analysis of variance. Effects of subcutaneous injection of ACTI3 hours before sacrifice were also observed. Incidental to this work, the adaptor of Lowry et al. (3) for USC of small volutnr sample tubes with the Farrand fluorometcr (model A) was modified in some details for greater convenience, and the fluorometer was modified to eliminate use of batteries. The analytical procedure of Lowry et al. (4) for PN and PSHl was applied with changes necessitated by the problem at hand.