The role of the kidney in plasma glucose regulation during
hyperglycemia.
Cersosimo, Eugenio, Mohamed Ajmal, Rebbeca J. Naukam, Patricia E.
Molina, Naji N Abumrad.
Departments of Medicine and Surgery, State University of New York
at Stony Brook, Stony Brook, NY 11794-8154
APStracts 4:0003E, 1997.
Little is known about the role of the kidney in plasma glucose
regulation during hyperglycemia. We studied 12 overnight fasted
conscious dogs after either intrarenal (IR, n=6) or peripheral (PH,
n=6) dextrose infusion to maintain hyperglycemia without glycosuria.
Systemic & renal glucose kinetics were measured with [6-3H]
glucose; lactate balance by AV difference; and glycogen content
assayed in the kidneys. Plasma glucose (_5.5 vs _6.3 mM); insulin
(_70 vs _110 pM); and glucose appearance (_14 vs _16 _mol.kg.-1min-1)
increased comparably in both groups (p<0.05). In IR,
fractional extraction of glucose (FEg) increased from 4.1+/-0.2% to
16.1+/-0.5% (p<0.001) and lactate balance reversed to renal
output (+1.3+/-0.2 vs -0.9+/-0.2 _mol.kg.-1min-1 , p<0.01).
Glycogen content was 2-fold higher in the left (127+/-33) than in the
right kidney (56+/-11 _g/g tissue, p<0.01). In PH, FEg
decreased from 4.9+/-0.6% to 2.2+/-0.3% (p<0.05); renal
glucose utilization did not change (_1.3 _mol.kg.-1min-1 ) and
glycogen content was equal in both kidneys (_45 _g/g tissue). We
conclude that, although, the kidney plays a minor role in plasma
glucose disposal in physiologic hyperglycemia, increased glucose
uptake, glycogen storage and lactate formation precede glycosuria and
may represent important mechanisms by which the kidney contributes to
normalization of plasma glucose in diabetes.
Received 8 July 1996; accepted in final form 23 December 1996.
APS Manuscript Number E316-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 21 January 1997