Abstract

The general objective of these investigations is to study the physiologic maturation of the fetal lamb kidney and quantitate the contribution of the fetal kidney in compensating for various types of fetal distress. Specific investigations are designed to study: 1. The relative rates of maturation of renal blood flow, intracortical distribution of renal blood flow, and glomerular capillary flow utilizing radioactive microspheres. 2. The factors affecting the maturation of renal blood flow. 3. The influence of fetal hypoxemia on renal blood flow, gl merular capillary flow and glomerular filtration rate, and factors that may influence the response of the fetal kidney to hypoxemia. 4. The relation between the rate of filtraton in the cortical nephrons versus the juxtamedullary nephrons during gestation and immediately after birth utilizing a modification of the Hanssen Technique and C14 sodium ferrocyanide, and relate these findings to the distribution of glomerular capillary flow. These studies will provide valuable information leading to a better understanding of the fetus's response to intrauterine stress and the adjustment made during recovery. Furthermore, it will provide valuable physiological data which may stimulate new concepts regarding intrauterine therapy and management of the fetus during high risk pregnancy. Finally, these fetal studies will permit us to know where the developmental processs stands when a premature birth happens, and will help the survival of premature infants.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK038302-12
Application #
3237551
Study Section
Cardiovascular and Pulmonary Research B Study Section (CVB)
Project Start
1977-08-01
Project End
1991-07-31
Budget Start
1988-08-01
Budget End
1989-07-31
Support Year
12
Fiscal Year
1988
Total Cost
Indirect Cost

  Institution

Name
University of Iowa
Department
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242

  Publications

Nuyt, A M; Segar, J L; Holley, A T et al. (2001) Autonomic adjustments to severe hypotension in fetal and neonatal sheep. Pediatr Res 49:56-62
Mazursky, J E; Segar, J L; Nuyt, A M et al. (1996) Regulation of renal sympathetic nerve activity at birth. Am J Physiol 270:R86-93
Merrill, D C; Thompson, M W; Carney, C L et al. (1996) Chronic hypertension and altered baroreflex responses in transgenic mice containing the human renin and human angiotensinogen genes. J Clin Invest 97:1047-55
Guillery, E N; Mathews, M S; Orlowski, J et al. (1996) Angiotensin II and the maturation of renal cortical Na+/H+ exchanger activity during fetal life in sheep. Am J Physiol 271:R1507-13
Nuyt, A M; Segar, J L; Holley, A T et al. (1996) Arginine vasopressin modulation of arterial baroreflex responses in fetal and newborn sheep. Am J Physiol 271:R1643-53
Guillery, E N; Karniski, L P; Mathews, M S et al. (1995) Role of glucocorticoids in the maturation of renal cortical Na+/H+ exchanger activity during fetal life in sheep. Am J Physiol 268:F710-7
Segar, J L; Bedell, K; Page, W V et al. (1995) Effect of cortisol on gene expression of the renin-angiotensin system in fetal sheep. Pediatr Res 37:741-6
Robillard, J E; Page, W V; Mathews, M S et al. (1995) Differential gene expression and regulation of renal angiotensin II receptor subtypes (AT1 and AT2) during fetal life in sheep. Pediatr Res 38:896-904
Merrill, D C; McWeeny, O J; Segar, J L et al. (1995) Impairment of cardiopulmonary baroreflexes during the newborn period. Am J Physiol 268:H1343-51
Merrill, D C; Segar, J L; McWeeny, O J et al. (1994) Cardiopulmonary and arterial baroreflex responses to acute volume expansion during fetal and postnatal development. Am J Physiol 267:H1467-75

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