Warburton D, Parton L, Buckley S, Cosico L, Saluna T
Department of Pediatrics, University of Southern California School of Medicine, Children's Hospital of Los Angeles 90027.
J Appl Physiol (1985). 1987 Aug;63(2):828-33. doi: 10.1152/jappl.1987.63.2.828.
We correlated the ontogeny of pulmonary beta-adrenergic receptors with the onset of surface active material (SAM) flux into tracheal fluid of male and female chronically catheterized fetal lambs. SAM flux began between 0.82 and 0.85 gestation in the females and between 0.85 and 0.89 gestation in the males and matured more rapidly thereafter in the females than in the males (P less than 0.01). beta-Adrenergic receptor binding, using [3H]dihydroalprenolol as the ligand, was saturable, linear, and stereospecific. The order of potency of competitive beta-agonists was isoproterenol greater than norepinephrine greater than epinephrine. The maximal binding capacity (Bmax) of pulmonary beta-receptors approximately doubled between 0.84 and 0.89 gestation, coinciding with the onset of SAM flux. Bmax matured as a third degree polynomial function of gestational age in females (r = 0.9, P less than 0.001) but as a linear function in males (r = 0.8, P less than 0.005). Between 0.86 and 0.93 gestation, Bmax was 1.45-fold greater in females than males (P less than 0.001). The dissociation constant of beta-receptors was not influenced significantly by gender or gestation. We conclude that maturation of pulmonary beta-receptors coincides with the onset of SAM flux in fetal lambs and that both mature more rapidly in females. We speculate that pulmonary beta-receptor maturation and SAM flux are coregulated by hormonal factors. More rapid maturation of pulmonary beta-receptors and SAM flux in females may be a factor in the female advantage with regard to pulmonary surfactant maturation and the survival of premature neonates.
我们将肺β-肾上腺素能受体的个体发生与长期插管的雄性和雌性胎羊气管液中表面活性物质（SAM）流量的开始相关联。雌性胎羊的SAM流量在妊娠0.82至0.85之间开始，雄性胎羊在妊娠0.85至0.89之间开始，此后雌性胎羊的SAM流量比雄性胎羊成熟得更快（P小于0.01）。以[³H]二氢心得舒作为配体，β-肾上腺素能受体结合具有饱和性、线性和立体特异性。竞争性β-激动剂的效力顺序为异丙肾上腺素大于去甲肾上腺素大于肾上腺素。肺β-受体的最大结合容量（Bmax）在妊娠0.84至0.89之间大约增加了一倍，与SAM流量的开始相吻合。在雌性胎羊中，Bmax作为胎龄的三次多项式函数成熟（r = 0.9，P小于0.001），而在雄性胎羊中则作为线性函数成熟（r = 0.8，P小于0.005）。在妊娠0.86至0.93之间，雌性胎羊的Bmax比雄性胎羊高1.45倍（P小于0.001）。β-受体的解离常数不受性别或妊娠的显著影响。我们得出结论，肺β-受体的成熟与胎羊SAM流量的开始相吻合，并且两者在雌性胎羊中成熟得更快。我们推测肺β-受体成熟和SAM流量受激素因素共同调节。雌性胎羊中肺β-受体和SAM流量更快的成熟可能是雌性在肺表面活性物质成熟和早产新生儿存活方面具有优势的一个因素。
