title: beta-Adrenergic receptors in the developing rabbit lung.
abstract: beta-Adrenergic receptors and catecholamine-sensitive adenylate cyclase were identified and partially characterized in membrane fractions of rabbit lungs from day 25 of gestation to adulthood with the beta-adrenergic antagonists (--)-[3H]dihydroalprenolol [(--)-[3H]DHA] and (--)-[125I]iodohydroxybenzylpindolol [(--)-[125I]HYP]. beta-Adrenergic receptor number (Bmax) increased 11.5-fold during this time period, increasing progressively during the latter days of gestation and the early neonatal period, from 37 +/- 10 fmol/mg protein at 25 days gestation to 425 +/- 51 fmol/mg in the adult rabbit lung (mean +/- SD). Receptor affinity for (--)-[3H]DHA (KD = 1.8 nM) or (--)-[125I]HYP (KD - 0.104 nM) and the proportion of beta 1- and beta 2-adrenergic receptor subtypes (60% beta 1 and 40% beta 2) did not change with advancing age. Basal adenylate cyclase activity in lung homogenates decreased significantly with increasing age, whereas the activity in the presence of catecholamine or NaF remained nearly constant. Catecholamines stimulated adenylate cyclase activity at all ages studied supporting a role of the maturation of beta-adrenergic receptors in the regulation of pulmonary function.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D005260:Female; D008168:Lung / Q000196:embryology* / Q000201:enzymology / Q000378:metabolism; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011247:Pregnancy; D011817:Rabbits; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; C011878:iodohydroxybenzylpindolol; D004082:Dihydroalprenolol; D010869:Pindolol; D000262:Adenylyl Cyclases