Development of pulmonary vascular response to oxygen

Journal Article · Tue Mar 01 00:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6808837

Ferguson, W; Lundgren, C E ^[1]

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1. State Univ. of New York, Buffalo (USA)

The ability of the pulmonary circulation of the fetal lamb to respond to a rise in oxygen tension was studied from 94 to 146 days of gestation. The unanesthetized ewe breathed room air at normal atmospheric pressure, followed by 100% oxygen at three atmospheres absolute pressure in a hyperbaric chamber. In eleven near-term lambs, fetal arterial oxygen tension (Pa{sub O{sub 2}}) increased from 25 to 55 Torr, which increased the proportion or right ventricular output distributed to the fetal lungs from 8 to 59%. In five very immature lambs fetal Pa{sub O{sub 2}} increased from 27 to 174 Torr, but the proportion of right ventricular output distributed to the lung did not change. In five of the near-term lambs, pulmonary blood flow was measured. For each measurement of the distribution of blood flow, approximately 8 {times} 10{sup 5} spheres of 15-{mu}m diameter, labeled with either {sup 153}Gd, {sup 113}Sn, {sup 103}Ru, {sup 95}Nb, or {sup 46}Sc were injected. It increased from 34 to 298 ml {center dot} kg fetal wt{sup {minus}1} {center dot} min{sup {minus}1}, an 8.8-fold increase. The authors conclude that the pulmonary circulation of the fetal lamb does not respond to an increase in oxygen tension before 101 days of gestation; however, near term an increase in oxygen tension alone can induce the entire increase in pulmonary blood flow that normally occurs after the onset of breathing at birth.

• OSTI ID: 6808837
• Journal Information: American Journal of Physiology; (USA), Vol. 254:3; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BLOOD FLOW
RADIOASSAY
LUNGS
BLOOD CIRCULATION
BLOOD PRESSURE
GADOLINIUM 153
MICROSPHERES
NIOBIUM 95
OXYGEN
PHYSIOLOGY
RUTHENIUM 103
SCANDIUM 46
SHEEP
TIN 113
VASOCONSTRICTION
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
GADOLINIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MINUTES LIVING RADIOISOTOPES
NIOBIUM ISOTOPES
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANS
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RESPIRATORY SYSTEM
RUMINANTS
RUTHENIUM ISOTOPES
SCANDIUM ISOTOPES
SECONDS LIVING RADIOISO
TIN ISOTOPES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques