Renal glucose production in the intact dog

Dm, Roxe; DiSalvo, Joseph; Balagura-Baruch, S

doi:10.1152/ajplegacy.1970.218.6.1676

Cited by 12 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is important to distinguish between micromoles of glutamine converted to glucose and micromoles of glucose formed from glutamine. The (10,11). It must be emphasized that our method traces only glutamine into glucose.…”

Section: Resultsmentioning

confidence: 99%

Metabolism of Glutamine by the Intact Functioning Kidney of the Dog STUDIES IN METABOLIC ACIDOSIS AND ALKALOSIS

Pitts¹,

Pilkington²,

MacLeod³

et al. 1972

J. Clin. Invest.

View full text Add to dashboard Cite

A B S T R A C T The renal conversion of glutamine to glucose and its oxidation to COs were compared in dogs in chronic metabolic acidosis and alkalosis. These studies were performed at normal endogenous levels of glutamine utilizing glutamine-14C (uniformly labeled) as a tracer. It was observed in five experiments in acidosis that mean renal extraction of glutamine by one kidney amounted to 27.7 /Amoles/min. Of this quantity, 5.34 umoles/min was converted to glucose, and 17.5 umoles/min was oxidized to C02. Acidotic animals excreted an average of 41 omoles/min of ammonia in the urine formed by one kidney. In contrast, in five experiments in alkalosis, mean renal extraction of glutamine amounted to 8.04 umoles/min. Of this quantity, 0.92 umole/min was converted to glucose, and 4.99 ,tmoles/min was oxidized to C02. Alkalotic animals excreted an average of 3.23 ,.moles/min of ammonia in the urine. We conclude that renal gluconeogenesis is not rate limiting for the production and excretion of ammonia in either acidosis or alkalosis. Since 40% of total C02 production is derived from oxidation of glutamine by the acidotic kidney and 14% by the alkalotic kidney, it is apparent that renal energy sources change with acid-base state and that glutamine constitutes a major metabolic fuel in acidosis.

show abstract

Section: Resultsmentioning

confidence: 99%

Metabolism of Glutamine by the Intact Functioning Kidney of the Dog STUDIES IN METABOLIC ACIDOSIS AND ALKALOSIS

Pitts¹,

Pilkington²,

MacLeod³

et al. 1972

J. Clin. Invest.

View full text Add to dashboard Cite

show abstract

“…Scaglione et al (41) reported that lactate concentration in rats is about two to five times times greater at the papillary tip than that at the corticomedullary boundary, in good agreement with measurements in dogs performed by Dell and Winter (11). Glucose concentration has been reported to average 5.8 mM in the renal arteriole of the dog (38) and is expected to be lower in the renal medullary interstitium. As described in MODEL AND PARAMETERS, extrapolation of measurements by Bastin et al (4) suggests that that glucose concentration in rat kidney decreases from 5.9 to 2.3 mmol/l of interstitial tissue water over a 2-min period following dissection and under full ischemia, whereas lactate concentration increases from 6.5 to 16.6 mmol/l of interstitial tissue water over the same period.…”

Section: Resultsmentioning

confidence: 99%

“…As reviewed by Ross et al (37), although the contribution of renal glucogenesis to blood glucose has been estimated to be 5-25% under normal conditions, it is very likely that these figures are overestimated due to a number of technical difficulties. Conversely, the study of Roxe et al (38) in dogs suggested that the amount of glucose generated by renal gluconeogenesis is negligible. If a significant amount of glucose is indeed generated in the proximal tubules (37), part of it could also diffuse into the outer medullary microcirculation.…”

Section: Discussionmentioning

confidence: 95%

“…The main site of glycolysis in the kidney appears to be the IM and the papilla, as indicated by the mapping of glycolytic enzymes (37). Finally, glucose synthesis has been found to occur in the superficial and deep cortex and in the OM (17); Roxe et al (38), however, observed that the rate of renal gluconeogenesis in the dog is extremely low. As reviewed by Laris (24), glucose that is added to plasma can be entirely recovered, indicating that there is no consumption of glucose in plasma.…”

Section: Anaerobic Glycolysis In the Medullamentioning

confidence: 99%

“…Based on these experimental values, we estimate glucose concentration in renal arterial blood as 5.8 mM in the plasma phase and 2.8 mM in the RBCs. Roxe et al (38) also reported that glucose concentration in the renal arteriole of dog ranges from 3.2 to 7.7 mM and averages 5.8 mM. In the absence of more specific data in the glomerular efferent arterioles, the initial (i.e., at the corticomedullary junction in DVR) glucose concentration is taken as 6 mM in plasma and 3 mM in RBCs.…”

Section: Initial Concentrationsmentioning

confidence: 99%

See 2 more Smart Citations

A model of glucose transport and conversion to lactate in the renal medullary microcirculation

Zhang

Edwards

2006

American Journal of Physiology-Renal Physiology

View full text Add to dashboard Cite

Zhang, Wensheng, and Aurélie Edwards. A model of glucose transport and conversion to lactate in the renal medullary microcirculation. Am J Physiol Renal Physiol 290: F87-F102, 2006. First published August 23, 2005 doi:10.1152/ajprenal.00168.2005In this study, we modeled mathematically the transport of glucose across renal medullary vasa recta and its conversion to lactate by anaerobic glycolysis. Uncertain parameter values were determined by seeking good agreement between predictions and experimental measurements of lactate generation rates, as well as glucose and lactate concentration ratios between the papilla and the corticomedullary junction; plausible kinetic rate constant and permeability values are summarized in tabular form. Our simulations indicate that countercurrent exchange of glucose from descending (DVR) to ascending vasa recta (AVR) in the outer medulla (OM) and upper inner medulla (IM) severely limits delivery to the deep inner medulla, thereby limiting medullary lactate generation. If the permeability to glucose of OMDVR and IMDVR is taken to be the same and equal to 4 ϫ 10 Ϫ4 cm/s, the fraction of glucose that bypasses the IM is calculated as 54%; it is predicted as 37% if the presence of pericytes in OMDVR reduces the glucose permeability of these vessels by a factor of 2 relative to that of IMDVR. Our results also suggest that red blood cells (RBCs) act as a reservoir that reduces the bypass of glucose from DVR to AVR. The rate of lactate generation by anaerobic glycolysis of glucose supplied by blood from glomerular efferent arterioles is predicted to range from 2 to 8 nmol/s, in good agreement with lower estimates obtained from the literature (Bernanke D and Epstein FH. Am J Physiol 208: 541-545, 1965; Bartlett S, Espinal J, Janssens P, and Ross BD. Biochem J 219: [73][74][75][76][77][78] 1984). kidney; glycolysis; mathematical model THE URINARY CONCENTRATING mechanism is made possible by the steep corticomedullary osmolality concentration gradient, which is created and maintained by countercurrent exchange between the descending and ascending limbs of the loops of Henle, the collecting ducts, and the descending (DVR) and ascending vasa recta (AVR). However, the manner in which the hyperosmolality in the inner medullary interstitium is built up and preserved remains unclear. A hypothesis involving an external osmolyte proposed by Niesel and Roeskenbleck (30) and summarized by Kriz and Lever (23) has recently been examined by Jen and Stephenson (20) and Thomas and Wexler (43). These investigators showed that an unspecified solute, external to the tubular fluid, that can provide an added 20 -100 mosmol/l to the interstitial osmolality throughout the inner medulla (IM), may very significantly increase water reabsorption.Because of hypoxia in the IM, anaerobic glycolysis appears to be the dominant energy supply for IM metabolism (37).Lactate is produced by anaerobic glycolysis, and it may later be used for gluconeogenesis in the outer medulla (OM) and cortex (37). Because anaerobic glycol...

show abstract

Role of the kidneys in hyperglycemia provoked by anti-insulin serum in rats

Iynedjian

Peters

1974

Diabetologia

View full text Add to dashboard Cite

The hyperglycemic response to two 2-ml injections of guinea pig anti-insulin serum (GPAIS), given at a 1.5 h interval, was measured after 18 h of fast in nephrectomized rats, intact animals and animals with anuria caused by ligating the ureters. In controls plasma glucose rose by ~-196• rag/100 ml within 1.5 h after GPAIS injection, then levelled off with the onset of glucosuria and began to decline at 4.5 h. Anuria due to ureteral obstruction did not affect the initial rise of plasma glucose (~-197• ll.9mg/100ml at 1.5h). In contrast, the initial rise of plasma glucose amounted to only-~-136 ~ 5.3 mg/100 ml at 1.5 h in nephrectomized rats. Blood sugar remained lower in the latter animals than in those with ligated ureters for the rest of the experiment. The blunted glycemic response to GPAIS in anephrie rats, thus, is due to the loss of kidney tissue per se. It is suggested that, after sudden insulin deprivation, the kidneys might release sizeable amounts of newly synthesized glucose into the circulation.

show abstract

Renal glucose production in the intact dog

Cited by 12 publications

References 0 publications

Metabolism of Glutamine by the Intact Functioning Kidney of the Dog STUDIES IN METABOLIC ACIDOSIS AND ALKALOSIS

Metabolism of Glutamine by the Intact Functioning Kidney of the Dog STUDIES IN METABOLIC ACIDOSIS AND ALKALOSIS

A model of glucose transport and conversion to lactate in the renal medullary microcirculation

Role of the kidneys in hyperglycemia provoked by anti-insulin serum in rats

Contact Info

Product

Resources

About