The effects of lactate loading on alanine and glucose metabolism in the conscious dog.
The effect of lactate per se on alanine and glucose metabolism was studied in five overnight-fasted conscious dogs. Somatostatin was infused to inhibit endogenous pancreatic insulin and glucagon release and the hormones were replaced intraportally at basal rates. Saline (n = 5) or lactate (at 25 and 50 mumol.kg-1.min-1 for 90 minutes each) was infused, and blood samples were taken during the last 30 minutes of each 90-minute period. Insulin, epinephrine, norepinephrine, and cortisol levels remained unchanged during saline or lactate infusion. Glucagon level decreased slightly during lactate (94 +/- 7 to 74 +/- 9 and 79 +/- 8 pg/mL) and saline (91 +/- 8 to 90 +/- 4 and 81 +/- 11 pg/mL) infusions. There were no significant changes in lactate or alanine levels or net hepatic balances with saline infusion. Blood lactate level increased from 657 +/- 74 to 1,718 +/- 126 and 3,300 +/- 321 mumol/L (both P < .05) during the low- and high-lactate infusion periods, respectively. The liver produced lactate during the control (5.57 +/- 2.92 mumol.kg-1 x min-1) and low-lactate infusion (1.75 +/- 2.58 mumol.kg-1 x min-1) periods, but consumed lactate (3.89 +/- 3.31 mumol.kg-1 x min -1; P < .05) during the high-lactate infusion period.(ABSTRACT TRUNCATED AT 250 WORDS)
Connolly
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CC
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232.
Stevenson
R W
RW
Neal
D W
DW
Wasserman
D H
DH
Cherrington
A D
AD
D000409:Alanine / Q000378:metabolism*; D000818:Animals; D003243:Consciousness; D004285:Dogs; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005943:Gluconeogenesis; D005947:Glucose / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007659:Ketones / Q000378:metabolism; D007773:Lactates / Q000378:metabolism / Q000494:pharmacology*; D019344:Lactic Acid; D008102:Liver Circulation; D008297:Male
D005230:Fatty Acids, Nonesterified; D007659:Ketones; D007773:Lactates; D019344:Lactic Acid; D005947:Glucose; D000409:Alanine; D005990:Glycerol