Abstract
Exogenous β-agonists stimulate release of surfactant (SAM) and absorption of lung water, presumably through interaction with BAR. To evaluate the role of endogenous catecholamines in these processes, we injected fetuses (28-d gestation) with an irreversible BAR antagonist, bromacyl- (1-8) diamino-β-menthone alprenolol (B, 30-40 mg/kg) or vehicle. BAR concentration was reduced from 215±11 to 46±16 fmol/mg protein, measured by [125I] Cyanopindolol binding to lung particulate, with no change in KD or adenylate cyclase activity not mediated by BAR. SAM in lavage was decreased ∼30% in 2 nonbreathing groups (Table).
B appears to inhibit SAM release per se rather than synthesis since treatment did not affect tissue saturated phosphatidyl-choline, [3H] choline incorporation by lung minces, or phospholipid composition of lavage. In studies of lung water, B did not attact the decreases observed after vaginal vs c/s (no labor) delivery or after birth. We conclude that endogenous catecholamines participate in SAM but not water flux in the fetus.
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McDonald, J., Gonzales, L., Ballard, P. et al. 291 ROLE OF β-ADRENERGIC RECEPTORS (BAR) AND ENDOGENENOUS CATECHOLAMINES IN SURFACTANT RELEASE BUT NOT LUNG WATER ABSORPTION IN FETAL RABBITS. Pediatr Res 19, 159 (1985). https://doi.org/10.1203/00006450-198504000-00321
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DOI: https://doi.org/10.1203/00006450-198504000-00321