caa a22 4500 477120970 CHVBK 20180405111636.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00248456 doi (NATIONALLICENCE)springer-10.1007/BF00248456 Role of thyroid hormones in renal tubule acidification [Elektronische Daten] [Marcelo Morales, Henrique César, Purchio Brucoli, Gerhard Malnic, Aníbal Lopes] Renal tubule acidification was studied in thyroparathyroidectomized rats which had the parathyroids reimplanted into cervical muscle tissue, by stopped-flow microperfusion using ion-exchange resin microelectrodes. Hypothyroid rats had decreased rates of proximal and late distal bicarbonate reabsorption. This reduction occurred in the absence of changes in pH gradients, and was due mostly to decreases in acidification half-times, that is, of the rate of bicarbonate exit from the tubule lumen. H+ back-flux from the lumen measured during luminal perfusion with solutions at pH 6 (below stationary pH) was decreased in proximal tubule of hypothyroid rats, showing that the acidification defect was not due to an increased H+ shunt across the epithelium. These data indicate that in hypothyroid rats the proximal tubule luminal density of Na+/H+ exchangers or their turnover is decreased in the absence of alterations in the driving force (H+ and Na+ gradients across the luminal membrane) for H+ secretion. The effect observed in distal tubule may be due to action on Na+/H+ exchangers that are present also on this site, or to an impairment of the action of other H+ transporters such as H+-ATPases, including the provision of energy for them. Kluwer Academic Publishers, 1996 H+ nationallicence bicarbonate nationallicence thyroid hormones nationallicence hypothyroid rats nationallicence Morales Marcelo Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro, RJ, Brazil aut César Henrique Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro, RJ, Brazil aut Brucoli Purchio Department ofPhysiology and Biophysics, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil aut Malnic Gerhard Department ofPhysiology and Biophysics, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil aut Lopes Aníbal Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro, RJ, Brazil aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 154/1(1996-03-01), 17-21 0300-8177 154:1<17 1996 154 11010 https://doi.org/10.1007/BF00248456 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00248456 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Morales Marcelo Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro, RJ, Brazil aut NATIONALLICENCE 700 1- César Henrique Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro, RJ, Brazil aut NATIONALLICENCE 700 1- Brucoli Purchio Department ofPhysiology and Biophysics, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil aut NATIONALLICENCE 700 1- Malnic Gerhard Department ofPhysiology and Biophysics, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil aut NATIONALLICENCE 700 1- Lopes Aníbal Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro, RJ, Brazil aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 154/1(1996-03-01), 17-21 0300-8177 154:1<17 1996 154 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer