Effects of somatostatin on phosphate transport: Evidence for the role of basal insulin

Lau, Kai; Guntupalli, J.; Eby, B.

doi:10.1038/ki.1983.120

Cited by 18 publications

(6 citation statements)

References 22 publications

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“…Among the hormones examined, insulin is the only one that affected phosphate uptake in JTC-12 cells. Insulin stimulated phosphate transport in JTC-12 cells, a finding consistent with the results of studies performed in vivo and in vitro (DeFronzo et al, 1976;Lau et al, 1983;Hammerman et al, 1984).…”

Section: Effect Ofvarious Hormones and Phosphate Concentrations In Cusupporting

confidence: 89%

Characterization of Na+-dependent phosphate uptake in cultured kidney cells (JTC-12) from monkey

Takuwa¹,

Ogata²

1985

Biochemical Journal

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Phosphate uptake was studied in confluent monolayers of an epithelial-cell line (JTC-12) derived from monkey kidney. Phosphate uptake consisted of a saturable, Na+-dependent, component, which accounted for about 80% of the uptake, and a nonsaturable, Na+-independent, component. The saturable component was specifically dependent on the presence of extracellular Na+ and has an apparent Km value for phosphate of 0.12 mM at 137-mM-Na+, which is close to those reported in the brush-border membranes in mammalian kidneys. The presence of Na+ in the uptake solution decreased the Km for phosphate without affecting the Vmax. Phosphate uptake was inhibited by carbonyl cyanide p-trifluoromethoxyphenylhydrazone and ouabain, suggesting that phosphate transport is an active, energy-dependent, process and is dependent on an Na+ gradient across cell membranes. With respect to the effect of external Na+ concentration, a sigmoid relation was seen between the initial velocity of phosphate uptake and Na+ concentrations, and Hill analysis gave a Hill coefficient of 1.8. In the pH range 6.6-7.4, phosphate uptake declined with increasing pH. Phosphate uptake was stimulated when cells were cultured in the presence of insulin, and was also affected by changes in phosphate concentrations in cultured medium. These results indicate that JTC-12 cells have an Na+-dependent phosphate-transport system with many of the features of phosphate transport in the proximal tubule.

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Section: Effect Ofvarious Hormones and Phosphate Concentrations In Cusupporting

confidence: 89%

Characterization of Na+-dependent phosphate uptake in cultured kidney cells (JTC-12) from monkey

Takuwa¹,

Ogata²

1985

Biochemical Journal

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“…Proximal tubule phosphate transport was stimulated in hyperinsulinemic euglycemic rats (5). Hypoinsulinemia induced by somatostatin infusion in parathyroidectomized rats results in a decrease in proximal tubule phosphate transport (12). Brush border membrane vesicles prepared from dog isolated proximal tubules had an increase in sodium-dependent phosphate transport when insulin was added to the incubation media (1 1).…”

Section: Resultsmentioning

confidence: 99%

“…Although the above studies found no change in glomerular filtration rate, recent data suggests that insulin may increase glomerular filtration rate. Addition of physiologic concentrations of insulin to isolated perfused kidneys from male Sprague Dawley rats resulted in an increase in glomerular filtration rate (22 (4,5,11,12,23). Infusion ofinsulin in humans where the plasma glucose concentration was maintained at a constant level resulted in a decrease in phosphate excretion (4).…”

Section: Resultsmentioning

confidence: 99%

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Insulin stimulates volume absorption in the rabbit proximal convoluted tubule.

Baum¹

1987

J. Clin. Invest.

225

128

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The present in vitro microperfusion study examined whether insulin affects volume absorption (J.) in the proximal convoluted tubule (PCT). PCT were perfused with an ultrafiltrate-like solution and were bathed in a serum-like albumin solution. Addition of a physiologic concentration of 10-10 M insulin to the bathing solution resulted in a stimulation of J. and a more negative transepithelial potential difference (PD). There was a progressive stimulation of the lumen negative PD and J, with higher insulin concentrations. Maximal stimulation occurred at 10-" M bath insulin. The insulin-induced stimulation of volume reabsorption was also observed when glucose and amino acids were removed from the luminal perfusate. Direct examination of the effect of insulin on glucose, chloride, and bicarbonate absorption demonstrated that the transport of all these solutes was stimulated by insulin. Addition of insulin to the luminal perfusate had no affect on J,. These data show that insulin has a direct effect to stimulate J. in the proximal tubule.

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“…Acute and chronic metabolic acidosis in humans and in experimental animals is associated with an increase in the urinary excretion of phosphate [48][49][50][51][52][53][54]. Studies in experimental animals have shown that metabolic acidosis induces phosphaturia by impairing renal proximal tubular apical brush border membrane (BBM) sodium gradientdependent phosphate transport (Na/Pi cotransport) activity.…”

Section: Role Of Acidosis In Muscle and Physical Capacitymentioning

confidence: 99%

Posttransplant metabolic acidosis: a neglected factor in renal transplantation?

Ambühl

2007

Current Opinion in Nephrology &Amp; Hypertension

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Available evidence suggests a high prevalence of (compensated) metabolic acidosis after renal transplantation, presenting as low serum bicarbonate and impaired renal acid excretion. This condition is associated with relevant disorders in mineral metabolism and muscle function. Current knowledge about the effects of acidosis on renal electrolyte handling, mineral metabolism and protein synthesis suggests that acid/base derangements contribute to the muscle and bone pathology, as well as anemia, encountered after kidney transplantation. Consequently, posttransplant acidosis may be a relevant factor in the causal pathway of impaired physical capacity observed in this patient group.

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Effects of somatostatin on phosphate transport: Evidence for the role of basal insulin

Cited by 18 publications

References 22 publications

Characterization of Na+-dependent phosphate uptake in cultured kidney cells (JTC-12) from monkey

Characterization of Na+-dependent phosphate uptake in cultured kidney cells (JTC-12) from monkey

Insulin stimulates volume absorption in the rabbit proximal convoluted tubule.

Posttransplant metabolic acidosis: a neglected factor in renal transplantation?

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