Summerill R A, Lee K E
Q J Exp Physiol. 1985 Apr;70(2):169-76. doi: 10.1113/expphysiol.1985.sp002900.
When normal conscious dogs were given small doses of (NH4)2HPO4 by stomach tube to increase their plasma PO4, the rate of excretion of PO4 increased without change in creatinine clearance. After eating meat, increased PO4 excretion was accompanied by increase in both creatinine clearance and plasma PO4. The calculated rate of tubular reabsorption of PO4 did not change significantly after (NH4)2HPO4 administration, but there was a significant increase in PO4 reabsorption after meat; in comparison there was no change in SO4 reabsorption. Similarly, administration of certain amino acids, which caused an increase in creatinine clearance, also caused a significant increase in PO4 reabsorption. Administration of SO4 with PO4 had no significant effect on PO4 reabsorption. It appears from the results, that PO4 has an apparent tubular maximum rate of reabsorption (Tm) when plasma PO4 alone is varied; but this Tm is not a real maximum because PO4 reabsorption increases above this value after the administration of meat or amino acids, both of which cause an increase in glomerular filtration rate. There is no evidence to suggest that there is any inhibition of PO4 reabsorption by SO4 or amino acids.
当给正常清醒的狗经胃管给予小剂量的磷酸氢二铵（(NH4)2HPO4）以提高其血浆磷酸盐（PO4）水平时，磷酸盐的排泄率增加，而肌酐清除率不变。进食肉类后，磷酸盐排泄增加的同时肌酐清除率和血浆磷酸盐水平均升高。给予磷酸氢二铵后，计算得出的肾小管对磷酸盐的重吸收率没有显著变化，但进食肉类后磷酸盐重吸收显著增加；相比之下，硫酸盐（SO4）重吸收没有变化。同样，给予某些氨基酸导致肌酐清除率增加，也会使磷酸盐重吸收显著增加。同时给予硫酸盐和磷酸盐对磷酸盐重吸收没有显著影响。从结果来看，当仅改变血浆磷酸盐水平时，磷酸盐有一个明显的肾小管最大重吸收率（Tm）；但这个Tm不是真正的最大值，因为在给予肉类或氨基酸后，磷酸盐重吸收会超过这个值增加，而这两者都会导致肾小球滤过率增加。没有证据表明硫酸盐或氨基酸会对磷酸盐重吸收有任何抑制作用。
