Potassium Depletion Stimulates Beta-Subunit of Colonic H⁺-K⁺-ATPase in Mice

H+-K+-ATPase (HKA) is composed of two different subunits: an alpha and a beta subunit. Previous studies have shown that in the kidney gastric HKA (HKA alpha 1) predominates under normal dietary conditions while colonic HKA (HKA alpha 2) predominates under potassium depleted conditions [1]. The purpose of the current study was to elucidate the association between the beta and different alpha subunits from stomach, colon and kidney under normal and potassium depleted conditions. Black Swiss mice were fed a potassium-free diet for 2 weeks, beta subunit expression of HKA in stomach mucosae, colon mucosae and renal outer medulla was examined and compared between normal diet and potassium depleted diet. In wild type (WT) mice, the concentrations of the beta subunit under potassium deficient conditions were found significantly increased compared with normal dietary conditions in colon mucosae (8.27 ± 0.73 vs 6.62 ± 0.55 μg/μl, n = 7, p = 0.0416), whereas in cHKA (HKA alpha 2) mice colon mucosae, the concentrations of the beta subunit were statistically the same (5.05 ± 0.31 vs 4.76 ± 0.37 μg/μl, n = 13, p = 0.2833), and the concentration of the beta subunit stayed the same in renal outer medulla and stomach mucosae as well. The data indicate that potassium deficiency results in a significant increase in the levels of HKA beta subunit concentration in the colonic tissue of WT mice. The results indicate that the HKA beta subunit associates with the cHKA (HKA alpha 2) in order to mediate bicarbonate reabsorption under potassium depletion (hypokalemia)

Ghrelin对大鼠胃黏膜上皮细胞中H^＋ -K^＋ -ATP酶基因表达和活性的影响

为揭示Ghrelin对胃酸分泌的作用,从断奶大鼠中分离新鲜胃黏膜,培养胃黏膜上皮细胞,培养30 h后,试验组培养液更换为分别含有1×10-4μmol/L、1×10-3μmol/L、1×10-2μmol/L和1×10-1μmol/L Ghrelin的新鲜培养液,对照组换为不含Ghrelin的正常新鲜培养液。继续培养4 h后,收集培养液和细胞,分别测定细胞中H+-K+-ATPasemRNA表达和活性。结果表明:1×10-3μmol/LGhrelin可显著增加细胞中H+-K+-ATPasemRNA的表达(P<0.05),1×10-4μmol/L、1×10-3μmol/L和1×10-2μmol/L Ghrelin明显增加了胃黏膜上皮细胞中H+-K+-ATPase的活性。这表明Ghrelin体外作用于胃黏膜上皮细胞可刺激胃酸的分泌。

Ghrelin对大鼠胃蛋白酶和H^+-K^+-ATP酶活性的体外作用

从断奶大鼠中获得新鲜的胃粘膜,分离培养胃粘膜上皮细胞,培养30 h后,试验组换为分别含有1×10-4、1×10-3、1×10-2和1×10-1μmol/L生长素(Ghrelin)的新鲜培养液,对照组换为不含Ghrelin的正常新鲜培养液。继续培养4 h,收集培养液和细胞,分别测定培养液中胃蛋白酶活性和细胞中H+-K+-ATPase活性。试验结果表明:1×10-3μmol/L的Ghrelin可显著提高胃蛋白酶的活性(P<0.05),1×10-4、1×10-3和1×10-2μmol/L的Ghrelin显著提高胃黏膜上皮细胞中H+-K+-ATPase的活性(P<0.05)。表明Ghrelin体外作用于胃粘膜上皮细胞可刺激胃蛋白酶和胃酸的分泌。

Ghrelin对大鼠胃黏膜上皮细胞胃酸分泌的调节作用

目的:探讨Ghrelin对胃外分泌功能的作用.方法:从断奶大鼠中获得新鲜胃黏膜组织.分离培养胃黏膜上皮细胞,培养30h后,实验组换为分别含有1×10-4、1×10-3、1×10-2和1×10-1μmol/LGhrelin的新鲜培养液,对照组换为不含Ghrelin的正常新鲜培养液.继续培养4h,收集培养液和细胞,分别测定细胞的相对活性(MTT法)、培养液中胃蛋白酶活性、细胞中H+-K+-ATPasemRNA表达和活性.结果:实验组中细胞的相对活性与对照组相比没有发生明显的变化;1×10-3μmol/LGhrelin可显著提高胃蛋白酶的活性(P<0.05).1×10-3μmol/LGhrelin可显著增加细胞中H+-K+-ATPasemRNA的表达(P<0.05),1×10-4和1×10-3μmol/LGhrelin明显增加了胃黏膜上皮细胞中H+-K+-ATPase的活性(均P<0.05).结论:Ghrelin体外作用于胃黏膜上皮细胞可刺激胃蛋白酶和胃酸的分泌.

Flavonoids from the stems and leaves of Scutellaria baicalensis Georgi attenuate H_2O_2-induced oxidative damage to rat cortical neurons

Primary cultures of rat cortical neurons were treated with H2O2 in an in vitro model of free radical neurotoxicity. Flavonoids extracted from the stems and leaves of Scutellaria baicalensis Georgi, known as SSF, at concentrations of 18.98, 37.36 and 75.92 μg/mL, protected neurons against H2O2 injury in a dose-dependent manner. SSF increased cell survival, reduced lactate dehydrogenase release and inhibited malondialdehyde production. SSF also inhibited reductions in superoxide dismutase, glutathione peroxidase and Na＋-K＋-ATPase activities. These results in-dicate that SSF can protect rat cortical neurons against H2O2-induced oxidative injury.

二甲酸钾对断奶仔猪胃功能的影响

选用28日龄断奶、平均体质量在5～7 kg的（长×大）仔猪180头,研究二甲酸钾（Potassium diformate,KDF）对断奶仔猪胃酸分泌、胃蛋白酶活性、胃肠激素表达的影响。试验分为2组,对照组饲喂基础日粮,试验组在基础日粮中添加1%的KDF,试验期为14 d。结果表明：KDF对仔猪胃重、胃盐酸和乳酸含量、胃蛋白酶活性没有显著影响。试验组仔猪胃粘膜中生长抑素（Somatostain,SS）和胆囊收缩素（Cholecystokinin,CCK）的mRNA相对表达量显著低于对照组（P〈0.05）,质子泵（H＋-K＋-ATPase）mRNA表达显著高于对照组（P〈0.05）,而胃泌素（gastrin）mRNA水平没有影响。结果提示KDF能够通过调节胃粘膜中基因表达来影响仔猪胃酸分泌功能。