Lobular and cellular patterns of early hepatic glycogen deposition in the rat as observed by light and electron microscopic radioautography after injection of /sup 3/H-galactose
Very low hepatic glycogen levels are achieved by overnight fasting of adrenalectomized (ADX) rats. Subsequent injection of dexamethasone (DEX), a synthetic glucocorticoid, stimulates marked increases in glycogen synthesis. Using this system and injecting /sup 3/H-galactose as a glycogen precursor 1 hr prior to sacrifice, the intralobular and intracellular patterns of labeled glycogen deposition were studied by light (LM) and electron (EM) microscopic radioautography. LM radioautography revealed that 1 hr after DEX treatment, labeling patterns for both periportal and centrilobular hepatocytes resembled those in rats with no DEX treatment: 18% of the hepatocytes were unlabeled, and 82% showed light labeling. Two hours after treatment with DEX, 14% of the hepatocytes remained unlabeled, and 78% were lightly labeled; however, 8% of the cells, located randomly throughout the lobule, were intensely labeled. An increased number of heavily labeled cells (26%) appeared 3 hr after DEX treatment; and by 5 hr 91% of the hepatocytes were intensely labeled. Label over the periportal cells at this time was aggregated, whereas centrilobular cells displayed dispersed label. EM radioautographs showed that 2 to 3 hr after DEX injection initial labeling of hepatocytes, regardless of their intralobular location, occurred over foci of smooth endoplasmic reticulum (SER) and small electron-dense particles of presumptive glycogen, and in areas of SER and distinct glycogen particles. After 5 hrs of treatment with DEX, the intracellular distribution of label reflected the glycogen patterns characteristic of periportal or centrilobular regions.
- Research Organization:
- Department of Anatomy and Cell Biology, University of Cincinnati College of Medicine, Ohio
- OSTI ID:
- 6670757
- Journal Information:
- Am. J. Anat.; (United States), Vol. 170:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SOMATIC CELLS
AUTORADIOGRAPHY
BIOSYNTHESIS
GLYCOGEN
LIVER
METABOLISM
RATS
TRITIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BODY
CARBOHYDRATES
DIGESTIVE SYSTEM
GLANDS
LABELLED COMPOUNDS
MAMMALS
ORGANIC COMPOUNDS
ORGANS
POLYSACCHARIDES
RODENTS
SACCHARIDES
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques