Fuel and energy metabolism in fasting humans.

@article{citeulike:2875447, abstract = {Fuel and energy homeostasis was examined in six male volunteers during a 60-h fast by using a combination of isotopic tracer techniques ([3-3H]glucose, [2H5]glycerol, [1-14C]palmitate, and L-[1-13C]leucine) and indirect calorimetry. Plasma glucose concentration and hepatic glucose production decreased by 30\% with fasting (5.2 +/- 0.1 to 3.8 +/- 0.2 mmol/L and 11.8 +/- 0.5 to 8.2 +/- 0.6 mumol.kg-1.min-1, respectively, both P < 0.001) and glucose oxidation declined approximately 85\% (P < 0.01). Lipolysis and primary (intraadipocyte) free fatty acid (FFA) reesterification increased 2.5-fold (1.7 +/- 0.2 to 4.2 +/- 0.2 mumol.kg-1.min-1 and 1.5 +/- 0.4 to 4.2 +/- 0.8 mumol.kg-1.min-1, respectively, both P < 0.05). This provided substrate for the increase in fat oxidation (from 2.7 +/- 0.3 to 4.3 +/- 0.1 mumol.kg-1.min-1, P < 0.01), which contributed approximately 75\% of resting energy requirements after the 60-h fast and increased the supply of glycerol for gluconeogenesis. Proteolysis and protein oxidation increased approximately 50\% during fasting (P < 0.01 and P < 0.05, respectively). We conclude that the increase in FFA reesterification with fasting modulates FFA availability for oxidation and maximizes release of glycerol from triglyceride for gluconeogenesis.}, address = {Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2230.}, author = {Carlson, M. G. and Snead, W. L. and Campbell, P. J. }, citeulike-article-id = {2875447}, issn = {0002-9165}, journal = {The American journal of clinical nutrition}, keywords = {metabolism, parameter}, month = {July}, number = {1}, pages = {29--36}, posted-at = {2008-06-09 12:30:12}, priority = {2}, title = {Fuel and energy metabolism in fasting humans.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/8017334}, volume = {60}, year = {1994} }

TY - JOUR ID - citeulike:2875447 L3 - citeulike-article-id:2875447 TI - Fuel and energy metabolism in fasting humans. JF - The American journal of clinical nutrition VL - 60 IS - 1 SP - 29 EP - 36 AD - Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2230. SN - 0002-9165 N2 - Fuel and energy homeostasis was examined in six male volunteers during a 60-h fast by using a combination of isotopic tracer techniques ([3-3H]glucose, [2H5]glycerol, [1-14C]palmitate, and L-[1-13C]leucine) and indirect calorimetry. Plasma glucose concentration and hepatic glucose production decreased by 30% with fasting (5.2 +/- 0.1 to 3.8 +/- 0.2 mmol/L and 11.8 +/- 0.5 to 8.2 +/- 0.6 mumol.kg-1.min-1, respectively, both P < 0.001) and glucose oxidation declined approximately 85% (P < 0.01). Lipolysis and primary (intraadipocyte) free fatty acid (FFA) reesterification increased 2.5-fold (1.7 +/- 0.2 to 4.2 +/- 0.2 mumol.kg-1.min-1 and 1.5 +/- 0.4 to 4.2 +/- 0.8 mumol.kg-1.min-1, respectively, both P < 0.05). This provided substrate for the increase in fat oxidation (from 2.7 +/- 0.3 to 4.3 +/- 0.1 mumol.kg-1.min-1, P < 0.01), which contributed approximately 75% of resting energy requirements after the 60-h fast and increased the supply of glycerol for gluconeogenesis. Proteolysis and protein oxidation increased approximately 50% during fasting (P < 0.01 and P < 0.05, respectively). We conclude that the increase in FFA reesterification with fasting modulates FFA availability for oxidation and maximizes release of glycerol from triglyceride for gluconeogenesis. KW - metabolism KW - parameter AU - Carlson, MG AU - Snead, WL AU - Campbell, PJ PY - 1994/07// UR - http://view.ncbi.nlm.nih.gov/pubmed/8017334 ER -