Some key enzymes of steroid metabolism viz.-3 alpha-, 3 beta- and 17 beta- hydroxysteroid dehydrogenases (HSDH) in submandibular salivary gland of female rat were studied histochemically. The results showed that these enzyme activities exhibit variation in localization as well as intensity depending on the stages of estrous cycle. 3 alpha-HSDH activity appeared during metestrous stage and remained active through proestrous stage but waned off significantly during estrous stage, thereby indicating a stage-bound occurrence. Generally, the enzyme activities are intensely localized in the linning of granular and large collecting ducts than in acinar regions, indicating greater capacity for the steroid metabolic conversions in ducts. As regards the acini; it is suggested that the significance of these enzymes be considered as having modifying influence on metabolic patterns threat
