title: Effects of fasting on ketone body concentrations in healthy men of different ages.
abstract: This work was performed to assess age effects on fasting-induced hyperketonemia and to determine if measurement of cerebral glucose utilization by positron emission tomography after 6 to 8 hr of fasting is associated with hyperketonemia that could influence cerebral glucose metabolism. Acetoacetate and 3-hydroxybutyrate were assayed in venous blood from healthy men of various ages, subjected to an 18-hr fast. At 18 hr of fasting but not at 14 hr or earlier, 3-hydroxybutyrate concentrations were correlated significantly with age; concentrations of acetoacetate and 3-hydroxybutyrate were significantly higher than at earlier times in the fast, p less than or equal to .05, with elevations of 82% and 214% over baseline, respectively. Acetoacetate and 3-hydroxybutyrate concentrations were higher on the day when cerebral glucose utilization was determined than after a comparable fast at another time. The observed level of hyperketonemia, however, would not substantially influence cerebral glucose metabolism. The findings indicate that aging is associated with increased susceptibility to fasting-induced hyperketonemia.
mesh_terms: D020155:3-Hydroxybutyric Acid; D000090:Acetoacetates / Q000097:blood; D000328:Adult; D000368:Aged; D000375:Aging; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D005215:Fasting; D005947:Glucose / Q000378:metabolism; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D007657:Ketone Bodies / Q000097:blood*; D008297:Male; D008875:Middle Aged; D014055:Tomography, Emission-Computed
chemical_list: D000090:Acetoacetates; D006885:Hydroxybutyrates; D007657:Ketone Bodies; C016635:acetoacetic acid; D005947:Glucose; D020155:3-Hydroxybutyric Acid