Effects of total fasting or chronic food restriction on plasma endothelin levels in rats

We tested the effects of 24- and 48-h fasting and 40% calorie restriction stresses on plasma endothelin (ET)-1,2 levels in male Sprague-Dawley rats. Plasma ET-1,2 levels in pg/ml were lower in 24-h fasted rats (15.48 +/- 3.49), 48-h fasted rats (5.28 +/- 4.32), and in chronically food-deprived rats (R) (10.49 +/- 6.28) compared to ad lib-fed (AL) rats (21.23 +/- 9.38). The R rats were pair-fed 40% fewer calories than AL rats. We conclude that calorie restriction or total food deprivation stress decreases plasma ET-1,2 levels, unlike many other forms of physiological stress that have been shown to increase plasma ET-1,2 levels.