Pregnancy increases maternal ventilation. At high altitude where O2 availability is reduced and fetal growth retarded, increased ventilation raises arterial O2 saturation and may influence maternal well-being and fetal growth. The proposed research aims to determine the mechanisms by which maternal hypoxic ventilatory response is increased with pregnancy, the locus of pregnancy's effects, and the contribution of increased hypoxic responsiveness to the increased ventilation of pregnancy. We hypothesize that maternal ventilatory response to hypoxia increases with pregnancy as a result of increased progestin levels, progesterone receptor numbers, and metabolic rate. Studies will be carried out in human beings to determine the effect of increased progestin levels, progesterone receptor numbers, and metabolic rate on hypoxic ventilatory response; the influence of gender on these modulators of hypoxic responsiveness; and the contribution of the increased hypoxic ventilatory response to the increased maternal ventilation of pregnancy. Studies of carotid body and respiratory output in cats will seek to determine the locus at which pregnancy influences hypoxic ventilatory response. The studies may be important for understanding the changes that normally occur with pregnancy and the reasons why some women raise their ventilation and deliver larger babies at high altitude than others. They may also be important for understanding gender differences and hormonal influences on ventilatory control and contribute to the long-term objective of identifying the influence of maternal ventilation on O2 transport, maternal and fetal well-being and the process by which adaptation to high altitude may occur.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Modified Research Career Development Award (K04)
Project #
5K04HD000681-02
Application #
3073270
Study Section
Human Embryology and Development Subcommittee 2 (HED)
Project Start
1985-08-01
Project End
1990-07-31
Budget Start
1986-08-01
Budget End
1987-07-31
Support Year
2
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Colorado Denver
Department
Type
Schools of Medicine
DUNS #
065391526
City
Aurora
State
CO
Country
United States
Zip Code
80045
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Moore, L G (2000) Comparative human ventilatory adaptation to high altitude. Respir Physiol 121:257-76
Tatsumi, K; Pickett, C K; Jacoby, C R et al. (1997) Role of endogenous female hormones in hypoxic chemosensitivity. J Appl Physiol 83:1706-10
Zamudio, S; Palmer, S K; Droma, T et al. (1995) Effect of altitude on uterine artery blood flow during normal pregnancy. J Appl Physiol 79:7-14
Zamudio, S; Palmer, S K; Dahms, T E et al. (1995) Alterations in uteroplacental blood flow precede hypertension in preeclampsia at high altitude. J Appl Physiol 79:15-22
Zamudio, S; Leslie, K K; White, M et al. (1994) Low serum estradiol and high serum progesterone concentrations characterize hypertensive pregnancies at high altitude. J Soc Gynecol Investig 1:197-205
Tatsumi, K; Hannhart, B; Pickett, C K et al. (1994) Effects of testosterone on hypoxic ventilatory and carotid body neural responsiveness. Am J Respir Crit Care Med 149:1248-53
Zamudio, S; Droma, T; Norkyel, K Y et al. (1993) Protection from intrauterine growth retardation in Tibetans at high altitude. Am J Phys Anthropol 91:215-24
Theis, M K; Honigman, B; Yip, R et al. (1993) Acute mountain sickness in children at 2835 meters. Am J Dis Child 147:143-5
Zhuang, J; Droma, T; Sun, S et al. (1993) Hypoxic ventilatory responsiveness in Tibetan compared with Han residents of 3,658 m. J Appl Physiol 74:303-11

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