Renal Metabolic Rate by 31P Saturation Transfer Nmr in Hypotension in Vivo

Yahaya, Haliru; Freeman, Dominique M.; Holloway, Paul; Ross, B. D.

doi:10.1042/cs066035pa_pt2

Cited by 3 publications

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“…The greatest experience with saturation transfer studies of the kidney was reported by Freeman and co-workers using both perfused kidneys and kidneys in situ (24,26,27). Freeman et al (24) reported an ATP/O ratio of 2.45 for the perfused kidney and a ratio of 1.7-2.0 for the kidney in vivo, while Yahaya et al (26) reported an ATP/ 0 of 1.4 for the kidney in vivo.…”

Section: Measurement Ofatp-pi Exchangementioning

confidence: 93%

“…Freeman et al (24) reported an ATP/O ratio of 2.45 for the perfused kidney and a ratio of 1.7-2.0 for the kidney in vivo, while Yahaya et al (26) reported an ATP/ 0 of 1.4 for the kidney in vivo. Previous experiments by Koretsky et al (32) in this laboratory led to a calculated rate of ATP synthesis = 13 pmol/min/g wet wt.…”

Section: Measurement Ofatp-pi Exchangementioning

confidence: 96%

“…The creatine kinase reaction has been investigated in skeletal muscle, heart, and brain ( 18). The exchange between ATP and Pi, which represents the combined reactions of ATP synthesis and hydrolysis, has also been examined in isolated cells (19,20), perfused hearts (21-23, perfused kidney ( 2 4 ) , and the kidney in vivo (25)(26)(27). The validity of saturation transfer to determine the rate of oxidative ATP synthesis of the kidney in vivo was supported by Freeman et al (27), who reported an ATP/O of 2.5 for the perfused kidney and 1.7 for the kidney in vivo.…”

Section: Introductionmentioning

confidence: 99%

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³¹P NMR studies of ATP concentrations and P_i–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

Shine

Xuan

Weiner

1990

Magnetic Resonance in Med

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Previous investigators found that cyanide (CN-) is a potent inhibitor of renal Na+ transport, while the uncoupling agent 2,4-dinitrophenol (DNP) and fructose (both which lower ATP levels) are weak transport inhibitors. To examine the disparate effects of these substances measurements of ATP were performed, using 31P NMR, while simultaneously monitoring renal Na+ transport. Infusion of CN-, DNP, and fructose lowered whole kidney ATP levels by about the same extent (30%) while only CN- inhibited Na+ transport. This may be due to the fact that CN- has a potent action on the thick ascending limb of Henle, while fructose and DNP may have a more proximal action. Alternatively, ATP turnover may be a more important determinant of transport than ATP concentrations. Saturation transfer experiments were performed to measure Pi-ATP flux. Unilateral nephrectomy, high protein feeding, and methylprednisolone were used to stimulate metabolism and transport. The rate of Pi-ATP flux was 20.1 mumol/min/g. However, because oxygen consumption was stimulated, the ATP/O ratio was 0.85, considerably less than the theoretical value of 3. Finally, atrial natriuretic factor, which increased Na+ transport, had no effect on Pi-ATP flux. The results raise the possibility that the saturation transfer technique does not detect all Pi-ATP flux, especially when renal metabolism is stimulated.

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Section: Measurement Ofatp-pi Exchangementioning

confidence: 93%

Section: Measurement Ofatp-pi Exchangementioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

³¹P NMR studies of ATP concentrations and P_i–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

Shine

Xuan

Weiner

1990

Magnetic Resonance in Med

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NMR and the Study of Pathological State in Cells and Tissues

Ruı́z-Cabello

Cohen

1993

International Review of Cytology

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Magnetic resonance spectroscopy for the determination of renal metabolic rate in vivo

Freeman

Chan

Yahaya

et al. 1986

Kidney International

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The method of magnetic resonance spectroscopy has been validated and applied to the determination of renal metabolic rate in vivo. Using an indwelling detector coil, 31P NMR spectra from one kidney of anesthetized rats were quantified. The concentration of ATP was the same as that determined enzymatically, but both ADP and Pi were substantially lower. Only 25% of renal Pi and virtually none of the ADP were detected by NMR. The remainder is assumed to be bound to proteins. These concentrations of metabolites contributed to a significantly increased phosphorylation potential, which in turn should increase the free energy of hydrolysis of ATP. Saturation transfer, a non-destructive magnetic technique for the measurement of chemical exchange, was readily able to detect synthesis of ATP from ADP and inorganic phosphate. The rate of ATP synthesis determined was comparable to that determined in parallel studies of renal oxygen consumption. An ATP:O ratio of approximately 2 was found, indicating that fatty acid is the preferred fuel of respiration of the rat kidney in vivo.

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Renal Metabolic Rate by 31P Saturation Transfer Nmr in Hypotension in Vivo

Cited by 3 publications

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³¹P NMR studies of ATP concentrations and P_i–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

³¹P NMR studies of ATP concentrations and P_i–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

NMR and the Study of Pathological State in Cells and Tissues

Magnetic resonance spectroscopy for the determination of renal metabolic rate in vivo

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Renal Metabolic Rate by 31P Saturation Transfer Nmr in Hypotension in Vivo

Cited by 3 publications

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31P NMR studies of ATP concentrations and Pi–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

31P NMR studies of ATP concentrations and Pi–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

NMR and the Study of Pathological State in Cells and Tissues

Magnetic resonance spectroscopy for the determination of renal metabolic rate in vivo

Contact Info

Product

Resources

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³¹P NMR studies of ATP concentrations and P_i–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism

³¹P NMR studies of ATP concentrations and P_i–ATP exchange in the rat kidney in Vivo: Effects of inhibiting and stimulating renal metabolism