We measured hormonal levels in blood samples from pulmonary and radial arteries in 117 patients undergoing aorto-coronary by-pass surgery with the aim of investigating the role of the pulmonary vessel endothelium in hormone metabolism. Insulin and glucagon concentrations were significantly higher in pulmonary artery blood with respect to radial artery blood (73±65 vs. 65±47 pmol/l, p<0.005, and 80+49 vs. 73+51 ng/l, p<0.01, respectively), while no difference was found for growth hormone, prolactin, C peptide, insulin-like growth factor I, follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, parathyroid hormone, thyroglobulin, triiodothyronine, thyroxine, free triiodothyronine, and free thyroxine. Moreover, prolactin concentrations were more than twice the normal levels, this being an effect of propafol and the opiate fentanyl used for the general anesthesia. Assuming that the arteriovenous differences observed are a marker of peptide hormone degradation, our study has demonstrated that with similar kinetics insulin and glucagon secreted into portal circulation and escaping from hepatic extraction undergo further homeostatic removal of about 9-10 % in the pulmonary circulation before entering the general circulation., G. Aliberti, I. Pulignano, M. Proietta, F. Miraldi, L. Cigognetti, L. Tritapepe, C. Di Giovanni, R. Arzilla, E. Vecci, M. Toscano., and Obsahuje bibliografii
Lactate dehydrogenase (LDH) activity and its isoenzymatic fractions were measured in bone marrow blood and in peripheral venous blood from 16 haematologically normal subjects. Total LDH activity was significantly higher in marrow than in venous blood (428.8 ±98.4 vs 260.1 ±40.2 mU/1, p<0.0001). The same was true for the absolute values of its isoenzymatic fractions. The percentage fractions LDH 1 and LDH 5 were similar in the two regions, while LDH 3 and LDH 4 were higher in medullary blood (p<0.05) and LDH 2 was higher in peripheral blood (p<0.05). The Spearman test showed a limited correlation between marrow and peripheral total LDH activity values (p<0.05). This seems to be at least in part sustained by the highly significant correlations existing in LDH 3 and LDH 4 values, reported to be pre-eminent isoforms in maturing haematopoietic cells (p< 0.005 and p< 0.001, respectively). These findings could be attributed to an apoptotic regulation of marrow cell production.