PMID: 591480Nov 1, 1977

Placental diffusing capacity for carbon monoxide and oxygen in unanesthetized sheep

Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology
L D Longo, K S Ching


We measured placental diffusing capacity for carbon monoxide (DpCO) in 10 unanesthetized sheep with catheters chronically implanted in maternal and fetal vessels. Serially measured DpCO during the last third of gestation averaged 0.55 +/- 0.02 (SEM) ml.( fetal wt)-1, essentially the same value as that previously reported in anesthetized, acutely operated animals. While placental CO diffusing capacity increased as a function of gestational age when expressed as ml.(min.Torr)(-1), it remained constant when calculated per kg fetal wt. In eight experiments, DpCO showed no change following the administration of several drugs which combine with cytochrome P450. We interpret this as evidence against the carrier hypothesis for placental CO exchange. We calculated the placental diffusing capacity for oxygen to be 0.68 ml.( and the mean maternal-to-fetal capillary Po2 difference to be 10 Torr. Caculations predict that maternal and fetal oxygen partial pressures equilibrate in end-capillary blood during the course of a single transit in placental exchange vessels; thus placental oxygen exchange is not limited by diffusion.


Apr 20, 2019·Science Advances·Alexander ErlichIgor L Chernyavsky
Oct 1, 1984·Teratology·J Singh, L H Scott
Jan 6, 2010·Reproduction, Fertility, and Development·Natalee W Bessette, Dan W Rurak
Jan 1, 1995·Journal of Basic and Clinical Physiology and Pharmacology·H Sohmer, S Freeman
Jan 1, 2013·Annual Review of Animal Biosciences·Anthony M Carter, Allen C Enders
Dec 16, 2011·BMC Pregnancy and Childbirth·Carolina C VendittiGraeme N Smith
May 1, 1982·Journal of Toxicology. Clinical Toxicology·C R Cramer

Related Concepts

Carbon Monoxide
Cytochrome P-450 Oxygenase
Gestational Age
Maternal-Fetal Exchange
Oxygen Consumption
Dall Sheep

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Alzheimer's Disease: MS4A

Variants within the membrane-spanning 4-domains subfamily A (MS4A) gene cluster have recently been implicated in Alzheimer's disease in genome-wide association studies. Here is the latest research on Alzheimer's disease and MS4A.

Pediculosis pubis

Pediculosis pubis is a disease caused by a parasitic insect known as Pthirus pubis, which infests human pubic hair, as well as other areas with hair including eye lashes. Here is the latest research.

Rh Isoimmunization

Rh isoimmunization is a potentially preventable condition that occasionally is associated with significant perinatal morbidity or mortality. Discover the latest research on Rh Isoimmunization here.

Genetic Screens in iPSC-derived Brain Cells

Genetic screening is a critical tool that can be employed to define and understand gene function and interaction. This feed focuses on genetic screens conducted using induced pluripotent stem cell (iPSC)-derived brain cells. It also follows CRISPR-Cas9 approaches to generating genetic mutants as a means of understanding the effect of genetics on phenotype.

Enzyme Evolution

This feed focuses on molecular models of enzyme evolution and new approaches (such as adaptive laboratory evolution) to metabolic engineering of microorganisms. Here is the latest research.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Pharmacology of Proteinopathies

This feed focuses on the pharmacology of proteinopathies - diseases in which proteins abnormally aggregate (i.e. Alzheimer’s, Parkinson’s, etc.). Discover the latest research in this field with this feed.

Alignment-free Sequence Analysis Tools

Alignment-free sequence analyses have been applied to problems ranging from whole-genome phylogeny to the classification of protein families, identification of horizontally transferred genes, and detection of recombined sequences. Here is the latest research.