Light and electron microscopic study of liver glycogen heterogeneity

ABSTRACT

Seven ad-libidum fed rats and seven overnight fasted rats where used in this experiment. Their livers where subjected to enzymatic glycogen determination, PAS staining and E.M. examination. High glycogen content was detected in the livers of fed rats. The livers showed discrete glycogen particles in contact with vesicles of SER in cetrilobuar hepatocytes and glycogen lacks surrounded with few vesicles in periportal areas. Liver of fasted animals showed low glycogen level and marked reduction of glycogen content with extensive SER proliferation especially in centrilobular hepatocytes. The study provides evidence of the regional variation in ultrastructure and glycogen distribution in fasted and fed animals. The study reflects more light about the dynamic action of SER in relation to both hepatocytic glycogen deposition and depletion according to the nutritional status. The variation in strength and distribution of PAS staining of hepatocytes of fed rats could be clarified in light of their ultrastrucre and lobular location. A close relationship was observed between peroxisomes and both glycogen particles and SER suggesting a role of peroxisomes in glycogen synthesis. We recommend that the study of the ultrastructure of the liver should be always correlated to the nutritional status of the animals, a precise determination of liver glycogen level for each particular spacemen and accurate localization of the hepatocytes in relation to their lobular patern