Catecholamine levels and receptor expression in row protein rat offspring

Aims Low birthweight in humans has been shown to lead to increased resting pulse rate in adult life, suggesting possible increased sympathoadrenal act ivity. The hypothesis that early growth restriction is associated with perm anent alterations in catecholamine metabolism was tested. Methods Circulating catecholamine concentrations (by radioimmunoassay) and adipocyte adrenoceptor expression from different fat depots (by Western blo t) were estimated in 12-week-old male offspring of rat dams fed a reduced p rotein diet during pregnancy and lactation. Results In the fed state, median (interquartile range) plasma adrenaline co ncentrations for male control and low protein offspring rats were: 0.65 (0. 48-0.86) vs. 1.42 (0.89-1.87) nmol/l (P < 0.005), respectively. Equivalent noradrenaline concentrations were: 2.71 (2.16-3.46) vs. 3.45 (3.00-4.28) nm ol/l (P < 0.05). After 24 h starvation, plasma adrenaline concentrations of controls rose to become similar to those of low protein offspring: 1.03 (0 .95-1.31) vs. 1.41 (0.69-1.62) nmol/1 (P = 0.3), respectively. Noradrenalin e concentrations rose in both groups to become similar: 3.84 (3.33-4.54) vs . 4.32 (3.70-6.54) nmol/1 (P = 0.3). In epididymal adipocytes adrenoceptor expression (relative to that of controls) was: alpha (2A) 0.79 (0.66-0.94) (P = 0.08), beta (1) 2.60 (2.27-3.07) (P = 0.04), beta (3) 1.37 (1.27-1.46) (P = 0.02). Similar-pattern differences in adrenoceptor expression were ob served in subcutaneous and intra-abdominal adipocytes. Conclusions These results are consistent with the suggestion that long-term alterations in catecholamine metabolism are present in adult offspring of rats fed a reduced protein diet during pregnancy and lactation.