Fluid and HCO(3)(-) secretion is a vital function of all epithelia and is required for the survival of the tissue. Aberrant fluid and HCO(3)(-) secretion is associated with many epithelial diseases, such as cystic fibrosis, pancreatitis, Sjögren's syndrome, and other epithelial inflammatory and autoimmune diseases. Significant progress has been made over the last 20 years in our understanding of epithelial fluid and HCO(3)(-) secretion, in particular by secretory glands. Fluid and HCO(3)(-) secretion by secretory glands is a two-step process. Acinar cells secrete isotonic fluid in which the major salt is NaCl. Subsequently, the duct modifies the volume and electrolyte composition of the fluid to absorb the Cl(-) and secrete HCO(3)(-). The relative volume secreted by acinar and duct cells and modification of electrolyte composition of the secreted fluids varies among secretory glands to meet their physiological functions. In the pancreas, acinar cells secrete a small amount of NaCl-rich fluid, while the duct absorbs the Cl(-) and secretes HCO(3)(-) and the bulk of the fluid in the pancreatic juice. Fluid secretion appears to be driven by active HCO(3)(-) secretion. In the salivary glands, acinar cells secrete the bulk of the fluid in the saliva that is driven by active Cl(-) secretion and contains high concentrations of Na(+) and Cl(-). The salivary glands duct absorbs both the Na(+) and Cl(-) and secretes K(+) and HCO(3)(-). In this review, we focus on the molecular mechanism of fluid and HCO(3)(-) secretion by the pancreas and salivary glands, to highlight the similarities of the fundamental mechanisms of acinar and duct cell functions, and to point out the differences to meet gland-specific secretions.

中文翻译：

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胰腺和唾液腺液和 HCO3 分泌的分子机制。

流体和 HCO(3)(-) 分泌是所有上皮细胞的重要功能，是组织生存所必需的。异常的液体和 HCO(3)(-) 分泌与许多上皮疾病有关，例如囊性纤维化、胰腺炎、干燥综合征以及其他上皮炎症和自身免疫性疾病。在过去的 20 年里，我们对上皮液和 HCO(3)(-) 分泌，尤其是分泌腺的了解取得了重大进展。分泌腺分泌的液体和 HCO(3)(-) 是一个两步过程。腺泡细胞分泌等渗液，其中主要盐分是氯化钠。随后，管道修改流体的体积和电解质组成以吸收 Cl(-) 并分泌 HCO(3)(-)。腺泡和导管细胞分泌的相对体积以及分泌液电解质成分的改变因分泌腺而异，以满足其生理功能。在胰腺中，腺泡细胞分泌少量富含 NaCl 的液体，而导管吸收 Cl(-) 并分泌 HCO(3)(-) 和胰液中的大部分液体。液体分泌似乎是由活性 HCO(3)(-) 分泌驱动的。在唾液腺中，腺泡细胞分泌唾液中的大量液体，唾液中的液体由活跃的 Cl(-) 分泌物驱动，并且含有高浓度的 Na(+) 和 Cl(-)。唾液腺导管吸收 Na(+) 和 Cl(-)，并分泌 K(+) 和 HCO(3)(-)。在这篇综述中，我们重点关注胰腺和唾液腺分泌液体和 HCO(3)(-) 的分子机制，