Postnatal development of rat alpha- and beta-adrenergic receptors: A comparison between tissues

The rates of development of rat kidney α- and β-adrenoceptors were compared with those of heart and lung adrenoceptors in the same animals by direct binding studies using [(3)H]WB4101 (α1), [(3)H]yohimbine (α2) and [(125)I]HYP (β). Kidney α1 and β-adrenoceptors had reached adult concentrations 7 days after birth, while the α2-adrenoceptor concentration plateaued at 21 days. Lung β-adrenoceptor concentration was stable initially, then increased rapidly to adult levels by 18 days. In contrast, heart α1-and β-adrenoceptor concentrations were at mature levels at birth. In all tissues studied the increase in noradrenaline concentration was slower than the increases in adrenoceptor concentrations.