Effects of inhibitors and substitutes for chloride in lumen on p-aminohippurate transport by isolated perfused rabbit renal proximal tubules.
نویسندگان
چکیده
The transport step for p-aminohippurate (PAH) from cell to lumen across the luminal membrane of rabbit proximal tubules has not been adequately defined. To examine this process more closely, we determined the effects of possible transport inhibitors and substitutes for chloride on PAH secretion in isolated perfused S2 segments of rabbit proximal tubules. The addition of 4-acetamido-4'-isothiocyano-2,2' disulfonic stilbene (10(-4) M) to the perfusate irreversibly inhibited PAH secretion, whereas the addition of probenecid (10(-4) M) to the perfusate reversibly inhibited PAH secretion. PAH secretion was unaffected by thiocyanate replacement of chloride in the luminal perfusate, reversibly inhibited by 15 to 20% by methyl sulfate replacement, and irreversibly inhibited by isethionate replacement. Because the luminal membrane is at least as permeable to thiocyanate as to chloride, less permeable to methyl sulfate, and much less permeable to isethionate, these data suggest that the PAH transport step from cells to lumen does not require chloride in the lumen but does require a highly permeant anion. During inhibition of PAH transport from cells to lumen, PAH uptake across the basolateral membrane was also reduced, suggesting some type of feedback inhibition. The data are compatible with PAH transport across the luminal membrane by an anion exchanger, a potential-driven uniporter, both carriers, or a carrier that can function in both modes.
منابع مشابه
Effect of steviol on para-aminohippurate transport by isolated perfused rabbit renal proximal tubule.
An inhibitory effect of steviol, metabolite of the natural sweetener stevioside, on transepithelial transport of p-aminohippurate (J(PAH)) was observed in isolated S(2) segments of rabbit renal proximal tubules using in vitro microperfusion. Addition of steviol (0.01--0.25 mM) to the bathing medium significantly depressed J(PAH) (approximately 50--90%). This inhibitory effect was dose-dependent...
متن کاملFluid secretion in isolated proximal straight renal tubules. Effect of human uremic serum.
We have examined the effect of normal and uremic human sera on the transtubular flow of fluid in isolated perfused segments of rabbit proximal convoluted and straight renal tubules. Proximal convoluted and straight tubules absorbed fluid from the lumen when the external bath was normal rabbit serum. Normal human sera in the bath depressed net fluid absorption in both tubular segments, but more ...
متن کاملCharacteristics of phosphate transport in isolated proximal tubule.
The characteristics of inorganic phosphate transport in isolated perfused proximal tubules of the rabbit were examined using radioisotopic techniques. When tubules were perfused with an ultrafiltrate of rabbit serum, the mean lumen-to-bath flux of phosphate in the convoluted segment was 6.60 +/- 1.41 (SE) pmol/mm-min with a simultaneous back-to-lumen flux of 0.45 +/- 0.08. In the straight porti...
متن کاملFurosemide effect on isolated perfused tubules.
BURG, MI., L. STONER, J. CARDINAL, AND N. GREEN. Furosemide effect on isolated perfused tubules. Am. J. Physiol. 225(l): 119-124. 1973 .-Proximal convoluted tubules, thick ascending limbs of Henle’s loop, and cortical collecting tubules were dissected from rabbit kidneys, and perfused in vitro. The effect of the diuretic agent furosemide on electrolyte transport and electrical potential differe...
متن کاملProtein kinase C regulation of organic anion transport in renal proximal tubule.
Fluorescence microscopy and digital image analysis were used to examine the role of protein kinase C (PKC) in the control of organic anion (fluorescein, FL) transport in killifish renal proximal tubules. Phorbol ester (1-100 nM) reduced cellular and luminal accumulation of FL, and protein kinase inhibitors [staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, 10-1,000 nM] increased...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of pharmacology and experimental therapeutics
دوره 288 3 شماره
صفحات -
تاریخ انتشار 1999