Abstract
To study the relationship of plasma VP(pg/ml), β-EP(pg/ml) & PaO2(mmHg)during hypoxic stress,we exposed pregnant ewes & lambs to an FIO2 of 5 or 10% in N2 for 30 min.In 11 fetuses of ewes exposed to 10% FIO2,VP increased from 1.7±0.5 to 56±17.8(p<.001). In 6 newborn lambs with 10% FIO2,mean VP increased from 2.1±0.4 to 10.5±5.8(p<.005)while with 5% FIO2,VP increased to 421±138 (p <.001).Exposure of 7 ewes to 10% FIO2 produced no change in mean VP,yet with 5% FIO2 mean VP increased from 1.7±5 to 38.9±15.7. There were significant negative correlations(p <.001)between PaO2 and log VP in the fetal & newborn lamb.
Unlike VP control β-EP levels were higher (p <.01)in the fetus (134±31) & newborn(155±24)than in the ewe(50±11). Fetal β-EP increased during hypoxia to 544±81 (p < .01) & values were positively correlated(r=.63,p < .005)with log VP. Lambs & ewes exposed to 10% FIO2 had no increase in β-EP,while with 5% FIO2 mean β-EP increased to 532±158 & 150±17(p < .01). β-EP levels correlated with VP(r=.91,p < .001). VP & β-EP values during hypoxia were higher(p < .02) in fetuses < 130 days gestation than those > 130 days.
We conclude that hypoxia strongly stimulates the release of VP & β-EP into the peripheral blood. With advancing gestation the fetus becomes more responsive to hypoxia. Data suggest parallel but independent release of VP & β-EP during hypoxia.
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Stark, R., Daniel, S., Husaln, K. et al. 449 VASOPRESSIN (VP) RELEASE IN FETAL NEWBORN AND ADULT SHEEP INDUCED BY HYPOXIA: CORRELATION WITH β-ENDORPHIN IMMUNOACTIVITY (-EP) & PaO2. Pediatr Res 15 (Suppl 4), 515 (1981). https://doi.org/10.1203/00006450-198104001-00460
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DOI: https://doi.org/10.1203/00006450-198104001-00460