Effect of beta-adrenergic blockade on physiologic growth in the Wistar rat

The effect of propranolol (Pr) on body weight was studied in 144 Wistar rats of both sexes from weaning to 17 weeks of age. Pr was administered to 77 of these rats (chosen at random), in a dose of 100 mg/kg body weight daily. Body weights were monitored every third day throughout the study. During their 17th week of age, all the rats were weighed for the last time and then sacrificed. The following organs were carefully dissected and weighed: brain, thymus, lungs, heart, liver, kidneys, adrenals, testes and ovaries. Gain in body weight was significantly reduced in the propranolol treated animals compared to control in both sexes. Organ weights were also less in propranolol-treated rats except for the kidneys of both sexes and the heart and testes of the males. However, the ratio of most organ weights per body weight was greater, indicating that the inhibition of weight gain was less severe in those organs compared to that of total body weight.