Image analysis of the histochemical demonstration of glucose-6-phosphatase activity in rat liver

Activities of histochemically demonstrated glucose-6-phosphatase were quantified by computerized densitometry using image analysis in livers of female adult Wistar rats fed ad libitum and fasted 22 h before sacrifice. Mean optical densities along the path between small portal tracts and efferent hepatic venous branches and enzyme activities obtained from biochemical assays exhibited a strong positive correlation. The gradients of high periportal to lower perivenous glucose-6-phosphatase activities were analysed by profiles of optical density along these distances. Mapping optical densities in an image of equidensity range provided information on the distribution pattern of hepatic glucose-6-phosphatase over an extended two-dimensional area. This visualisation of histochemical enzyme reaction based on quantitative data supports the approach of sampling across the entire protal----hepatic venous distance disregarding parenchymal zonation. Utilities provided by computer assisted image analysis will have some bearing for further adequate quantitative description of liver function and structural make up.