LONG-TERM REGULATION OF BLOOD VOLUME BY THE FETUS

  • Anderson, Debra, (PI)

    Project: Research project

    Project Details

    Description

    Descriptions of the regulation of blood volume often fail to consider the
    possibility of at least two different mechanisms controlling plasma volume
    and red cell mass, and the relative importance of these mechanisms over
    time. Short-term experiments (24 hours) in the fetal lamb have shown a
    change in plasma volume in response to different stresses (e.g.,
    hemorrhage, hypoxia). No short-term responses of fetal red cell mass have
    been measured. The proposed study will examine the long-term mechanisms available to the
    fetal lamb for the maintenance of blood volume. Special consideration will
    be given to the regulation of fetal red cell mass. Experiments will be
    performed in chronically characterized fetal lambs over a period of three
    weeks to seven weeks (1) under control conditions, (2) in anephric fetuses,
    (3) during chronic hypoxia due to long-term reductions in fetal placental
    blood flow, (4) after an acute reduction in red cell mass (5) after a
    sustained reduction in red cell mass and (6) after a sustained increase in
    red mass. In addition, some fetal lambs will be ventilated in utero to
    study the effects of increased PO2 on fetal erythropoietin production.
    Finally, the rate of red blood cell production and destruction will be
    measured. Fetal red cell mass, plasma volume, hematocrit, blood pressures,
    maternal plasma osmolality, fetal urine production, urine osmolality, fetal
    plasma osmolality, urine production, urine osmolality and plasma hormone
    levels (catecholamines, plasma renin activity and erythropoietin) will be
    measured. Regulation of fetal blood volume is subject to constraints which do not
    exist in the adult. The proposed experiments will test the hypothesis that
    the differences between the adult and the fetus are due, in part, to the
    prevailing fetal oxygen tensions, the relative magnitude of fetal red cell
    turnover rate and the fetal growth rate. Additionally, a second hypothesis
    to be tested is that fetal long-tern responses to a reduction in red cell
    mass are different from the short-term responses.
    StatusFinished
    Effective start/end date4/1/903/31/95

    Funding

    • National Institutes of Health
    • National Institutes of Health
    • National Institutes of Health: $186,526.00
    • National Institutes of Health: $194,103.00

    ASJC

    • Medicine(all)

    Fingerprint Explore the research topics touched on by this project. These labels are generated based on the underlying awards/grants. Together they form a unique fingerprint.