Journal article
Renal Hemodynamic Responses to Hypoxemia during Development: Relationships to Circulating Vasoactive Substances
Pediatric research, Vol.23(2), pp.155-162
02/01/1988
DOI: 10.1203/00006450-198802000-00004
PMID: 3281120
Abstract
Chronically catheterized fetal lambs (n = 11, gestational age 111-139 days) and neonatal lambs (n = 20, postnatal age 4-30 days) were studied to explore during development the relationship of renal hemodynamic responses during hypoxemia to plasma epinephrine concentration (E), plasma norepinephrine concentration (NE), plasma arginine vasopressin concentration (AVP), and plasma renin activity (PRA). A low oxygen gas mixture (11.1 ± 0.1% 02) was administered for 30 min to the pregnant ewe or neonatal lamb to induce hypoxemia with maintenance of normal arterial pC02 and pH. Arterial blood pressure was recorded continuously and renal blood flow (RBF) was determined by the radiolabeled microsphere technique. Moderate hypoxemia (p02 16 ± 2 torr and 33 ± 6 torr in fetus and neonate, respectively) induced increases in E, NE (measured by radioenzymatic assay), and AVP (measured by radioimmunoassay) in both fetus and neonate. PRA (measured by radioimmunoassay) also increased in response to hypoxemia in neonatal lambs. The change in mean arterial pressure with hypoxemia (ΔMAP) was significant in fetuses (ΔMAP 8 ± 14%, p < 0.05) but not in lambs (ΔMAP 1 ± 10%, p > 0.5). Similarly, the change in renal blood flow with hypoxemia (ΔRBF) was significant (ΔRBF -51 ± 24%, p < 0.001) in fetuses but not in neonatal lambs (ΔRBF -9 ± 38%, p > 0.1). These results reflected a change in renal vascular resistance with hypoxemia (ΔRVR) that was significant in fetal lambs (ΔRVR 169 ± 168%,/p < 0.01) but not in neonatal lambs (ΔRVR 51 ± 180%, p > 0.2). The relationships of these renal hemodynamic responses to the measured vasoactive substances, and the influence of their interactions to produce these responses, were assessed by response surface regression analysis. The response surface regression model of responses to hypoxemia of E (ΔE), NE (ΔNE), AVP (ΔAVP), and PRA (ΔPRA) to ΔMAP and ΔRVR over the entire development period fit the data well (adjusted R20.8427 and 0.8274, respectively). AE was the most predictive of the components for both ΔMAP and ΔRVR (F ratio 7.89 and 7.25, respectively). Contour plots of the interaction of ΔE with postconceptional age and ΔNE demonstrated considerable age dependence of the relationship of ΔE and ΔNE to ΔMAP and ΔRVR during development. The results are consistent with the hypothesis that asynchronous maturation of vascular β-adrenergic (vasodila-tory) and α-adrenergic (vasoconstrictor) effector mechanisms occurs throughout the fetal/neonatal period.
Details
- Title: Subtitle
- Renal Hemodynamic Responses to Hypoxemia during Development: Relationships to Circulating Vasoactive Substances
- Creators
- Douglas N Weismann - University of IowaJean E Robillard - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Pediatric research, Vol.23(2), pp.155-162
- DOI
- 10.1203/00006450-198802000-00004
- PMID
- 3281120
- ISSN
- 0031-3998
- eISSN
- 1530-0447
- Number of pages
- 8
- Language
- English
- Date published
- 02/01/1988
- Academic Unit
- Molecular Physiology and Biophysics; Nephrology, Dialysis and Transplantation; Stead Family Department of Pediatrics; Medicine Administration
- Record Identifier
- 9984773400202771
Metrics
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