Histochemical Demonstration of 17- -Hydroxysteroid Dehydrogenase by Use of Tetrazolium Salt.

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Abstract
The 17[alpha]-hydroxy-steroid dehydrogenase (17B-enzyme) has been demonstrated histo-chemically by using DPN as cofactor and 2,2[image]-diphenyl-5,5[image] -di-(m-nitrophenyl)-3,3[image]-(4,4[image]-biphenylene)ditetrazolium chloride (NNT). Small blocks of tissue from rats were taken immediately upon sacrifice and frozen at -70[degree]C and sectioned at -20[degree]C at 5[mu]. Sections were incubated in a solution consisting of Tris (hydroxymethyl) aminomethane buffer pH 8.8, 60 m[image], magnesium chloride 6 m[image], DPN 1 m[image], NNT dissolved in N,N-dimethylformamide 0.56%, steroid dissolved in N,N-dimethylformamide 1.25 m[image]. The steroids used were estradiol and testosterone. A total of 21 different organs and tissues were tested histochemically for the 17B-enzyme. The only positive organs were the liver and small intestine. These were compared with diaphorase using DPNH as a substrate. The 17B-enzyme as demonstrated by the resulting formazan gave a fine deep blue precipitate within the cytoplasm of the cell. In the liver only the hepatic cells were involved. The enzyme was distributed evenly throughout the liver lobule differing from succinic dehydrogenase which is absent around the central vein. In the intestine the enzyme is distributed as fine formazan granules in the cytoplasm of the cell with accentuation of its luminal portion.