Not only were
ghrelin levels in the stress - exposed rats significantly higher 24 hours after the last stress exposure, as previously reported, they also
remained elevated 130 days later, roughly equivalent to 12 years in human lifespan.
Similar fructose increases have been reported in healthy volunteers who consumed fructose loads between 0.5 and 0.75 g / kg34 and in individuals who consumed fructose - sweetened beverages with mixed meals.35 Leptin and
ghrelin levels were indistinguishable following acute ingestion of glucose or fructose, a finding possibly attributable to the short time interval of observation; leptin
levels typically change 4 to 6 hours after glucose administration.36 Although fructose was previously reported to be less effective than glucose in suppressing
ghrelin, such differences may be attributable to the different conditions and timing of
ghrelin measurements.10 Little is known about the acute PYY response to fructose ingestion compared with glucose ingestion, although 1 study in rats found higher rather than lower PYY
levels after 24 hours of glucose but not fructose feeding.11 Whether such disparities are related to study design or species differences
remains uncertain.