Abstract
The volume of the nucleus, endoplasmic reticulum [ER, including Golgi complex], mitochondria and cytoplasmic ground substance was measured in rat hepatocytes by stereological methods. The Na content was also measured by flame photometry. Variations in Na content correlated significantly with variations in volume of nucleus and ER. From the correlation parameters, Na concentrations were estimated as follows: nucleus, 108 mM; ER (including Golgi complex) 27 mM; cytoplasm (including mitochondria and remaining organelles) 16 mM.