Gastric Adaptive Responses to Chronic Hypokalemia / 대한해부학회지

ABSTRACT

To date, most of data regarding H/K-ATPase have been derived from alterations of gene expression or enzymatic activity in kidney. But potassium balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. The digestive system is also expected to participate substantively in the regulation of systemic K+ homeostasis during chronic hypokalemia. This study was performed to analyze the expression and distribution of the gastric H/K-ATPase alpha subunit mRNA and protein in rats of chronic changes of potassium diet using Northern blot analysis and immunohistochemistry. Northern blot analysis demonstrate that gastric H/K- ATPase alpha subunit mRNA was abundantly expressed in normal rat stomach not in distal colon. In experimental groups, gastric H/K-ATPase alpha subunit mRNA was also abundantly expressed, but there was no significant differences among all groups. By immunohistochemistry, immunoreactivity of gastric H/K-ATPase alpha subunit was detected in the parietal cells. Reaction products were diffusely localized throughout the cytoplasm. Most of these immunoreactive cells were located in the gastric gland between the neck and base portion of the body, but a few cells in the base or gastric pits. All groups exhibited comparable cellular patterns of labeling and signal intensity. These results suggest that gastric H/K-ATPase alpha subunit does not significantly contribute to potassium conservation during chronic changes of potassium diet in spite of abundant expression.