Cold-restraint stress and urinary endogenous beta-phenylethylamine excretion in rats.

Stress applied to humans increases the urinary excretion of the endogenous amphetamine-like substance beta-phenylethylamine (PEA), a potentially common mediator of amphetamine and stress effects. The present study was conducted to determine if cold-restraint stress in the rat could represent an animal model for stress-induced changes in PEA disposition in humans. The stressor markedly elevated the urinary excretion of endogenous PEA in a manner that was not attributable to changes in urinary pH, glomerular filtration rate or in food consumption. In addition, a large diurnal variation in PEA excretion was noted. The data suggest that the variables responsible for stress-induced alterations in endogenous PEA disposition in humans and rats are generally similar. However, they also indicate that in rats, in contrast to humans, PEA disposition is subject to diurnal changes.