Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1984-3-5
pubmed:abstractText
Human and rat placental homogenates contain inner ring deiodinase activity (PT4ase) towards T4 and T3. This activity may decrease the transfer of T4 and T3 across the placenta and influence thyroid hormone disposal in the fetal circulation. Data are now presented on human PT4ase in subcellular fractions, the Km of human PT4ase, and the effects of drugs and other compounds on human and rat PT4ase. The specific activity (nanograms of rT3 produced per min/mg protein) of each fraction of human placenta was as follows: nuclear, 0.07; mitochondrial, 0.15; lysosomal, 0.19; microsomal, 1.30; and cytosol, 0.01. The apparent Michaelis-Menton (Km) for PT4ase in human placental microsomes was 1.2 X 10(-7) M. T3, 3,3'-diiodothyronine, iopanoic acid, iodoacetic acid, diamide, and propranolol all exhibited dose-dependent inhibition of human and rat PT4ase when tested in the presence of 10 mM dithiothreitol (DTT). Propylthiouracil did not inhibit PT4ase at 10 mM DTT, but when the DTT concentration was lowered to 0.25 mM, up to 71% inhibition was noted. Many drugs, as noted in other organs with respect to outer and inner ring iodothyronine deiodinases, inhibited human PT4ase. These studies may be relevant to the practice of administering propylthiouracil, propranolol, and iopanoic acid to pregnant women.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-972X
pubmed:author
pubmed:issnType
Print
pubmed:volume
58
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
280-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
The effects of propylthiouracil, iodothyronines, and other agents on thyroid hormone metabolism in human placenta.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't