Microcalorimetric studies on uraemic plasma

The heat production by human plasma in healthy and uraemic subjects has been measured by direct isothermal microcalorimetry. The plasma from uraemic subjects displayed an increased heat production compared to that of normal plasma. The heat production by plasma from healthy subjects, but not by that from uraemic patients, was both proportional to the amount of thiol groups in the plasma and also to the oxidation of the thiol groups. The oxygen consumption of uraemic plasma was proportional to the heat production. The heat production by samples from uraemic patients was significantly correlated to the plasma concentration of creatinine, whereas no such correlation was found between the concentration of urea and heat production of such samples.