Transferrin secretion and hepatocyte ploidy: analysis at the single cell level using a semi-automatic image analysis method.

In a previous work it was shown that transferrin (Tf) secretion is directly related to the membrane surface area of hepatocytes (Péchinot D. et al. [31]). The aim of the present work was to search for a possible relationship between Tf secretion and hepatocytic ploidy using a semi-automatic image analysis method. A determination of Tf secretion by isolated normal adult hepatocytes was achieved at the single cell level, using a modified reverse hemolytic plaque test. A Feulgen reaction was also performed on these hepatocytes. It allowed the evaluation, for each secreting hepatocyte, of the quantity of Tf secreted and its nuclear characteristics. Discrimination between diploid (2c) and tetraploid (4c and 2c2c) hepatocytes was performed and the amount of Tf secreted by each subpopulation determined. It appeared that a 2-fold secretion ratio was not found between tetraploid and diploid hepatocytes. These results suggest, as Tf production is not directly proportional to the degree of ploidy of hepatocytes, that some not yet elucidated regulatory mechanisms may act on Tf gene expression.