title: The tissue-blood partition coefficient of iodoantipyrine in pig brain and its change with age.
abstract: The tissue-blood partition coefficient of 125I-labelled iodoantipyrine was measured in pig brain. The mean coefficient for 11 neonatal piglets (aged 0.5 to 4 days) was 0.718 mL/g (SD 0.083). Measurements in a further 11 animals up to 144 days old (at which time pigs are sexually mature), showed that the partition coefficient increased significantly with age, possibly as a result of the accumulation of brain lipid during growth. The change in partition coefficient with age was curvilinear, rising to unity as the animals reached maturity. There were significant differences between the partition coefficients in grey and in white matter, but these were so small relative to the differences between pigs that they could be neglected for all practical purposes. Since the accuracy of measurement of cerebral blood flow (CBF) by the Kety-Schmidt technique depends directly on the partition coefficient of the tracer, it is important to confirm that apparent changes of CBF do not simply reflect alterations in the partition coefficient rather than real changes in blood flow.
mesh_terms: D000367:Age Factors; D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D000983:Antipyrine / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D013552:Swine
chemical_list: D000983:Antipyrine; C008135:iodoantipyrine