Abstract
Adrenergic mechanisms are important in the regulation of pulmonary surfactant metabolism. We gave SKF29661, a specific inhibitor of adrenal epinephrine synthesis to 15 pregnant New Zealand White rabbits to study the role of fetal adrenal epinephrine in the regulation of alveolar surfactant (AS) content in the immediate neonatal period. Does were given 0, 25, 50 and 100 mg/kg/d starting at 20 days gestation. Fetuses were delivered at 31 days by C-section (term:31 days). One-half of each litter was sacrificed immediately and the remainder were allowed to breathe for one hour and then sacrificed. After sacrifice, the adrenals were immediately removed; one was assayed for catecholamine content, and the other for PNMT activity. A thorough alveolar wash was then performed to recover the AS. Total AS phosphatidylcholine (PC) was determined by thin layer chromatography. SKF 29661 caused significant reduction in adrenal E content at each dosage (p<.001); maximal effect was 57% reduction at 100 mg/kg/day. There was a progressive decrease in alveolar PC with increasing dosage of SKF29661 (p<.01). Furthermore, adrenal E in both treated and control animals correlated positively with alveolar PC (r=0.450, p<.001). Conclusions: 1) SKF29661 crosses the placenta and inhibits fetal adrenal E production; 2) reduced fetal adrenal E is associated with decreased alveolar PC. These results suggest that in the neonatal period, endogenous E release plays an important role in the regulation of AS possibly by increasing secretion.
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Padbury, J., Jacobs, H., Lam, R. et al. ENDOGENOUS EPINEPHRINE (E) SECRETION REGULATES SURFACTANT RELEASE. Pediatr Res 18 (Suppl 4), 144 (1984). https://doi.org/10.1203/00006450-198404001-00304
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DOI: https://doi.org/10.1203/00006450-198404001-00304