Active sulfate reabsorption in the proximal convolution of the rat kidney: Specificity, Na+ and HCO 3 ? dependence
- 1 January 1980
- journal article
- research article
- Published by Springer Nature in Pflügers Archiv - European Journal of Physiology
- Vol. 383 (2), 159-163
- https://doi.org/10.1007/bf00581877
Abstract
Using the standing droplet technique in the proximal convolution and simultaneous microperfusion of the peritubular capillaries, the decrease in luminal sulfate concentration with time and the zero net flux transtubular concentration difference of sulfate (\(\Delta c_{{\text{SO}}_{\text{4}}^{{\text{2 - }}} } \)) at 45 s was determined — the latter being taken as a measure of the rate of active sulfate reabsorption. Starting with 0.5 mmol/l sulfate in both perfusates the\(\Delta c_{{\text{SO}}_{\text{4}}^{{\text{2 - }}} } \) value of 0.35 mmol/l was approached exponentially with a half value time of 4.3 s. The\(\Delta c_{{\text{SO}}_{\text{4}}^{{\text{2 - }}} } \) values in the early proximal and late proximal convolution did not deviate from each other. If the Na+ concentration in the perfusates was reduced, the\(\Delta c_{{\text{SO}}_{\text{4}}^{{\text{2 - }}} } \) approached zero and extrapolated to a slightly negative value (ci>co). When 1 mmol/l ouabain was added to the perfusates\(\Delta c_{{\text{SO}}_{\text{4}}^{{\text{2 - }}} } \) decreased by 66% (the latter experiments were performed in the golden hamster which is more sensitive to ouabain than the rat). 1 mmol/l thiosulfate diminished\(\Delta c_{{\text{SO}}_{\text{4}}^{{\text{2 - }}} } \) by 68% and 1 mmol/l molybdate by 24%. Omitting or replacing bicarbonate by HEPES or glycodiazine reduced the sulfate reabsorption significantly, while acetazolamide (0.1 mmol/l) and increasing the CO2-pressure from 4.66 to 14.0 kPa (i.e. 5–15% CO2) had no effect. SITS 1 mmol/l had no effect on sulfate reabsorption. The data indicate that the sulfate reabsorption is driven by a Na+ gradient and inhibited by thiosulfate and molybdate, i.e. molecules which have a similar tetrahedral molecule structure. The sulfate reabsorption depends in an undefined manner on the presence of bicarbonate ions.
Keywords
This publication has 22 references indexed in Scilit:
- Sulphate-ion/sodium-ion co-transport by brush-border membrane vesicles isolated from rat kidney cortexBiochemical Journal, 1979
- Phosphate transport in the proximal convolution of the rat kidneyPflügers Archiv - European Journal of Physiology, 1978
- Chloride and sulfate transport in ehrlich ascites tumor cells: Evidence for a common mechanismJournal of Cellular Physiology, 1978
- Phosphate transport in the proximal convolution of the rat kidneyPflügers Archiv - European Journal of Physiology, 1978
- Urinary Sulfate Excretion in Children with Classic Renal Tubular AcidosisAnnals of Nutrition and Metabolism, 1978
- A study of the relationship between inhibition of anion exchange and binding to the red blood cell membrane of 4,4′-diisothiocyano stilbene-2,2′-disulfonic acid (DIDS) and its dihydro derivative (H2DIDS)The Journal of Membrane Biology, 1976
- Renal proximal tubular buffer-(glycodiazine) transportPflügers Archiv - European Journal of Physiology, 1975
- Dual action of acetazolamide and furosemide on proximal volume absorption in the rat kidneyKidney International, 1972
- The role of bicarbonate and other buffers on isotonic fluid absorption in the proximal convolution of the rat kidneyPflügers Archiv - European Journal of Physiology, 1971
- Micropuncture and Microanalysis in Kidney PhysiologyPublished by Springer Nature ,1969