ISSN:
1432-2013
Keywords:
Proximal Kidney Tubule
;
Mercurials
;
SH Reagents
;
Site Group Reagents
;
Transtubular Transport
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The effects of site group reagents were tested on the following transport processes of the proximal convolution. Isotonic Na+ absorption, evaluated by the shrinking droplet procedure, histidine and glucose transport, evaluated by measuring the respective transtubular concentration difference at zero substance and water net flux. The test substances were applied either by continuous microperfusion of the peritubular capillaries or by luminal perfusion prior to the transport tests or by addition to the luminal test solution. The SH reagents (0.2 mM) N-ethylmaleimide,p-chloromercuribenzoate (pCMB) 3,6-bis-(acetatomercurimethyl)dioxane and Mersalyl (Salyrgane) caused 50% inhibition of the isotonic Na+ absorption in approximately 1.5 min when applied to the capillary perfusate. The same effect was reached in 2–3 min by 0.2 mMp-chloromercuriphenylsulfonate, benzamido-4-iodo-acetylstilbene-2,5-disulfonate and 2,2′-dihydroperoxy-2,2′-dibutylperoxide. However, the large molecular SH reagentspCMB-dextran T10 and benzoxanthene-3,4-dicarboxylic-N-iodoacetyloligoprolyl-2-aminoethylimid, did not inhibit the isotonic Na+ absorption. If an inhibitory effect was observed on the Na+ transport its onset was faster, when the substance was applied from the blood site than when it was given from the tubular lumen. Because SH reagents inhibit the isotonic Na transport faster when applied from the blood side, and because SH reagents with MW up to 690 are inhibitory whereas larger ones with MW over 1700 are not, it seems that they exert their inhibitory action on SH groups located a) predominantly on the blood side and b) deep within the membrane and not at the surface. Histidine- and glucose transport was inhibited only when the sodium transport was inhibited considerably. The oxygen consumption of teased kidney slices is not inhibited by 0.2 mMpCMB or Mersalyl within 10 min, but it is inhibited considerably by 1 mM of these substances in the same period of incubation time. The COOH reagents N,N′-carbonyl-diimidazole and N-ethyl-N′-(3-dimethyl-aminopropyl)carbodiimid (10 mM) and the NH2 reagents 4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid, 2 Na+ (SITS) (1 mM) as well as danslychloride (applied from the lumen at 5 mM in paraffin oil) did not inhibit the isotonic Na+ absorption.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00587441
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