APPLICATION OF CLINICAL TEST KITS TO HISTOCHEMISTRY. I. ENZYMATIC DETERMINATION AND STAINING OF TOTAL CHOLESTEROL

Three types of commercially available test kits, used routinely in the colorimetric determination of human serum cholesterol, were applied to histochemistry. All kits tested were applicable to the homogenates of the adrenal gland, brain, adipose tissue, heart, liver and pancreas of the rat. Determinar TC (Kyowa Hakko), Cholescolor 500 (Ono Yakuhin) and Biochem. Test Combination (Boehringer Mannheim) were comparable in the determination of total cholesterol in these homogenates. The highest concentration of cholesterol was detected in the adrenal gland, followed by the cerebrum, adipose tissue, liver, heart and pancreas. When applied to unfixed slices of the brain, only with Determinar TC was a satisfactory result obtained. However, the colour complex developed with the enzyme method on these sections was unable to be recognized under a light micriscope. A modification of Determinar TC, i. e., a mixture (2: 1) of the enzyme solution without a colour developer and of diaminobenzidine (60mg/ml) solution, was applied to cryostat or tissue-sectioner sections of glutaraldehyde-fixed tissues. The adrenal cortex and brown adipose tissue stained most intensely. A drop of OsO4, when applied to a stained section, markedly accentuated density. With an elimination of ingredients to disperse the colour complex and with increased peroxidase, this method could be further modified for application to electron microscopic cytochemistry.