抄録
Human albumin has one free sulfhydryl group which has been reported to be highly oxidized in various renal and hepatic dysfunctions. However, the oxidation mechanism still is not clear. The isolated rat salivary gland allow us to sample intercellular fluids, venous effluent and saliva, thus to understand the site of oxidation through capillary, across vascular wall or through paracellular route. The rat submandibular gland was isolated and perfused with the perfusate containing commercial human albumin. The collected samples were analyzed by our special HPLC system.
The findings indicated that: 1) despite the evidence that the salivary gland has no intrinsic secretion system of human albumin, small amount of the albumin could be detected in the saliva at 1 μM carbachol stimulation and its concentration was approximately 0.1-0.5% of that in the perfusate; 2) a distinguishing feature was existence of S-nitrosoalbumin fraction only in saliva, and its concentration was approximately 10-20% of that in the salivary albumin; 3) in the salivary gland, the intercellular passage tended to increase an irreversible albumin fraction which was directly oxidized by reactive oxygen species. These facts suggested that the human albumin in saliva might be passed through the paracellular pathway such as tight junction in rat submandibular gland and modification of the albumin might be occurred during the pathway. [Jpn J Physiol 54 Suppl:S72 (2004)]
