Effects of different anti-aging dietary restrictions on endothelin-1 receptors in rat lung

male Sprague-Dawley rats, fed nd libitum (AL) or subjected to quantitative restriction to 60% of daily food intake (DR), and to every-other-day feeding (TF). Competition experiments with ET-1 (1pM-100nM) and with BQ-123 (1pM-50mM) were performed. Affinity was in the range of nM. Density resulted 4038+/-1185 and 4656+/-1100 fmol/mg protein for 3 and 24 months-old AL rats, and 1970+/-556 and 1533+/-270 for DR and IF rats while ET-A/ET-B was 49:51*, 65:35#, 48:52, 37:63 respectively (*p< 0.05 vs 24 months AL, #p < 0.05 vs DR, p< 0.01 vs LF). Aging seems to be associated with a tendency to increase of the density of ET-1 receptors and with a significant alteration of receptor subtype distribution.