Morphological Adaptive Responses of Gastric Parietal and Colonic Surface Epithelial Cells to Chronic Changes in Dietary Potassium / 대한해부학회지

Potassium (K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. It has been established that chronic potassium depletion is associated with a remarkable hypertrophy of the collecting duct of the kidney. But, there is no morphological studies regarding the stomach and distal colon during the chronic changes of potassium diet. Electron microscopy was performed to observe the morphological alterations of the stomach and distal colon in response to chronic changes of potassium diet in rat. Electron microscopy of normal parietal cells revealed the presences of many mitochondia, tubulovesicles, and short basal cytoplasmic processes and microvilli in the intracellular canaliculi. In potasium-depleted parietal cells, mito-chondria were increased in size and number, and tubulovesicles almost disappeared, and microvilli in the intracellular canaliculi were increased in number and length, and short basal cytoplasmic processes were also increased in size and number. Parietal cells of potassium-loading after restriction were found to be almost normal. Two types of surface columnar epithelial cells were present in normal distal colon. Type I cells had many mitochondria and abundant coated vesicles in the supranuclear region. Type II cells had moderate amount of mitochondria and relatively fewer coated vesicles. In comparison with normal, potasium-depleted surface columnar epithelial cells had more abundant and larger mitochondria and more numerous and longer (1.4~1.6 times than normal) microvilli. Surface columnar epithelial cells of potassium-loading after restriction were recovered almost to normal. These results suggest that gastric parietal cells and surface columnar epithelial cells of distal colon adapt through morphological changes to preserve potassium balance during chronic changes of potassium diet.

DISTRIBUTION, CLONING AND AMPLIFICATION SEQUENCE ANALYSIS OF GnRH GENE IN CULTURED GASTRIC PARIETAL CELLS OF RATS / 解剖学报

Objective To study the distribution and sequence analysis of gonadotropin releasing hormone (GnRH) gene in cultured gastric parietal cells of rats. Methods The distribution of GnRH molecule and GnRH mRNA were observed out through immunohistochemical ABC methods and in situ hybridization methods in cultured gastric parietal cells of rats. After isolation of the total RNA from the parietal cells, RT PCR was conducted to obtain GnRH cDNA. Then, the products of PCR was purified, digested by the restriction enzyme of Hind Ⅲ and EcoR Ⅰ, and DNA fragments interests were cloned into pUC19 vector. The products of PCR were analyzed by sequenceing with Sanger's method after identified by PCR and digestion of restriction enzyme. Results Gastric parietal cells showed GnRH immunoreactivity, positive material was located in cytoplasm with negative nuclei. GnRH mRNA hybridized signals were also detected in cytoplasm with negative nuclei. The specific amplified band of GnRH mRNA was detected through agarose gel electrophoresis and gene sequence is identical to the GnRH which has been reported in rat hypothalamus.Conclusion Our data suggest that GnRH could be produced by gastric parietal cells of rats and may modulate physiological function of gastric parietal cells of rats.\;[