11beta-hydroxysteroid dehydrogenase in subcellular particulates of rat submandibular salivary gland

11beta-hydroxysteroid dehydrogenase (11beta-HSD) was studied in intracellular components of the rat submandibular salivary gland. The difficulty in retaining 11beta-HSD activity during fractionation was overcome by using soybean trypsin inhibitor. Relatively pure subcellular particles were obtained by altering the initial centrifugal speeds used for the various fractions. 11beta-HSD was found to have its main activity in the crude nuclear fraction of the gland. Pure nuclei were isolated by centrifuging the crude nuclear fraction through 1.8-M sucrose at high speed, and these were found to retain the major enzyme activity. It was hypothesized that 11beta-HSD may influence genetic expression processes in salivary gland, but further work will have to be undertaken to investigate this possibility.