Bushinsky D A
Nephrology Program, Pritzker School of Medicine, University of Chicago, Illinois 60637.
Am J Physiol. 1988 Mar;254(3 Pt 2):F306-10. doi: 10.1152/ajprenal.1988.254.3.F306.
During acute metabolic acidosis there is a net influx of protons into bone, decreasing the elevated proton concentration. Whether there is an influx of protons into bone during acute respiratory acidosis is not known. To determine the effect of respiratory acidosis on net proton flux (JH) relative to bone, we compared JH from neonatal mouse calvariae incubated for 3 h in medium acidified by an increase in PCO2 (respiratory acidosis) with that from calvariae incubated in medium acidified to the same extent by a decrease in bicarbonate concentration (metabolic acidosis). The initial medium pH with respiratory acidosis was not different from that with metabolic acidosis (7.108 +/- 0.005 vs. 7.091 +/- 0.007, respectively, P = NS). During respiratory acidosis there was no JH from bone relative to the medium (JH = 236 +/- 93 neq.bone-1.3h-1, P = NS vs. 0); however, during metabolic acidosis there was net proton influx from the medium into bone (JH = -703 +/- 108, P less than 0.05 vs. 0, P less than 0.001 vs. respiratory acidosis). There was less calcium efflux from bone during respiratory than during metabolic acidosis (JCa = 68 +/- 6 nmol.bone-1.3 h-1 vs. 100 +/- 9, respectively, P less than 0.001). There is a net influx of protons into bone in vitro during acute metabolic, but not during acute respiratory, acidosis. The smaller calcium efflux during respiratory acidosis may indicate less net bone mineral dissolution and thus less buffer release into the medium.
在急性代谢性酸中毒期间，质子会净流入骨骼，从而降低升高的质子浓度。目前尚不清楚在急性呼吸性酸中毒期间是否有质子流入骨骼。为了确定呼吸性酸中毒对相对于骨骼的质子净通量（JH）的影响，我们将新生小鼠颅骨在因PCO2升高而酸化的培养基（呼吸性酸中毒）中孵育3小时后的JH与在因碳酸氢盐浓度降低而酸化至相同程度的培养基（代谢性酸中毒）中孵育的颅骨的JH进行了比较。呼吸性酸中毒时初始培养基pH与代谢性酸中毒时无差异（分别为7.108±0.005和7.091±0.007，P=无显著性差异）。在呼吸性酸中毒期间，相对于培养基没有来自骨骼的JH（JH=236±93纳摩尔·骨骼-1·3小时-1，与0相比P=无显著性差异）；然而，在代谢性酸中毒期间，有质子从培养基净流入骨骼（JH=-703±108，与0相比P<0.05，与呼吸性酸中毒相比P<0.001）。与代谢性酸中毒相比，呼吸性酸中毒期间骨骼的钙外流较少（JCa分别为68±6纳摩尔·骨骼-1·3小时-1和100±9，P<0.001）。在急性代谢性酸中毒而非急性呼吸性酸中毒期间，体外有质子净流入骨骼。呼吸性酸中毒期间较小的钙外流可能表明骨骼矿物质净溶解较少，从而向培养基中释放的缓冲物质也较少。
