RESUMO
By means of microparticles labelled by radioactive strontium 85Sr (3M, USA) the authors in two experiments established cardiac output and local blood flow through bones and certain other organs and tissues of rats in two distinct age categories (35 and 90 days, 45 and 110 days). The results of both experiments showed 1) significant decrease of blood flow in skull, lumbar vertebrae, distal epiphysis, distal metaphysis and thighbone diaphysis and tibia in older rats of both sexes (proof of previous results with 86Rb), 2) constantly significant decrease of blood flow through a skin sample taken from the ventral side of the trunk and 3) nonconstant increase of blood flow through kidneys of older rats. The causes of observed changes are not known, physiological importance to be supposed particularly as regards the circulatory changes in bones, is also not clear.
Assuntos
Envelhecimento/fisiologia , Circulação Sanguínea , Animais , Feminino , Masculino , Ratos , Radioisótopos de EstrôncioRESUMO
By means of microparticles labelled by radioactive strontium 85Sr (3M, USA) the authors in two experiments established cardiac output and local blood flow through bones and certain other organs and tissues of rats in two distinct age categories (35 and 90 days, 45 and 110 days). The results of both experiments showed 1) significant decrease of blood flow in skull, lumbar vertebrae, distal epiphysis, distal metaphysis and thighbone diaphysis and tibia in older rats of both sexes (proof of previous results with 86Rb), 2) constantly significant decrease of blood flow through a skin sample taken from the ventral side of the trunk and 3) nonconstant increase of blood flow through kidneys of older rats. The causes of observed changes are not known, physiological importance to be supposed particularly as regards the circulatory changes in bones, is also not clear.
Assuntos
Envelhecimento/fisiologia , Circulação Sanguínea , Animais , Velocidade do Fluxo Sanguíneo , Débito Cardíaco , Feminino , Masculino , RatosRESUMO
Retention of radioactive strontium 85Sr (18,5 kBq i.e. 0.5 microCi i.p.)--concerning the whole body and in distal epiphysis, distal metaphysis and in the thigh bone diaphysis--was followed up in two similar experiments for the period of 5-6 weeks in rats of both sexes and different age (younger category 40-45 days, older category 120-140 days). In both experiments bone retention 85Sr in older female rats is lower than in younger female rats. In male rats similar difference has not been constantly proved. Retention seems to be higher in female rats in comparison with males in the category of young rats. On the contrary in the category of older rats the retention is lower in female rats. In epiphysis and diaphysis of the thigh bone the differences are analogous to whole body differences; 85Sr reacts in the opposite way in distal metaphysis--retention is here extensively higher in older rats than in younger ones. The results obtained confirm the conclusion interesting from the point of view of clinical problem: avidity of the skelet to administered radioactive strontium is in younger female rats higher than in young male rats. However it is severely declining especially in female rats--in the second experiment as far as the level significantly lower than in male rats of the same older age category.
