Microcalorimetric investigation of metabolism in rat hepatocytes cultured on microplates and in cell suspensions.
In the present work, heat production rate in rat hepatocytes has been measured by use of thermopile heat conduction calorimeters. Both hepatocytes cultured in monolayers on microplates and hepatocytes in suspensions were used for microcalorimetric measurements. The highest heat production rate was found in newly cultured cells; thereafter, a gradual decrease was noted. After 1 day of culture, metabolic activity had reached a steady state that lasted about 4 days. A cell-density dependence of heat production was found, both in cell suspensions and in cultured hepatocytes on microplates. Higher cell concentration in the calorimeter ampoule was accompanied by decreasing heat production per cell. The heat output recorded for hepatocytes cultured on microplates (25 X 10(3) cells) was found to be 0.327 +/- 0.13 nW per cell after 24-48 h. Addition of sodium azide and sodium fluoride to tissue culture medium reduced heat production rate in cultured hepatocytes by 60 and 20%, respectively. Recording of heat production with the present calorimetric technique is relatively simple and fast, and offers the possibility to perform measurements in small samples of cultured hepatocytes on microplates, thus allowing long-term as well as repeated measurements on the same cell population.
D000818:Animals; D001386:Azides / Q000494:pharmacology; D002151:Calorimetry; D002452:Cell Count; D002470:Cell Survival; D002478:Cells, Cultured; D046508:Culture Techniques / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D019810:Sodium Azide; D012969:Sodium Fluoride / Q000494:pharmacology; D013997:Time Factors
D001386:Azides; D012969:Sodium Fluoride; D019810:Sodium Azide