[Specificity of the histochemical determination of sorbitol dehydrogenase--comparative indicator and immunohistochemical studies on the rat kidney].

We have investigated the distribution of sorbitol dehydrogenase by comparative indicator- and immunohistochemical technique in rat kidney. In this connection we have tested some parameters which influence the histochemical demonstration of SoDH-activity by tetrazolium salt indicator technique (e.g. prefixation of tissue sections, elution behaviour of SoDH, influence of different dialysis membranes, composition of incubating medium). According these studies, the enzyme was demonstrated in native cryostate sections by membrane incubating method. For the immunohistochemical demonstration of SoDH specific antibodies were prepared against this enzyme in rabbits, and were used for indirect immunofluorescence method and for the unlabelled antibody enzyme (PAP) technique. A good agreement of sorbitol dehydrogenase localization was obtained with all the tested methods, but also some discrepancies was observed in enzyme topic (e.g. glomeruli). The results are discussed under methodical aspects in connection with the specifity of the used methods to localize the enzyme.