Labeling of hepatic glycogen after short- and long-term stimulation of glycogen synthesis in rats injected with 3H-galactose

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · American Journal of Anatomy; (USA)

DOI:https://doi.org/10.1002/aja.1001880410· OSTI ID:6422829

Michaels, J E; Garfield, S A; Hung, J T; Cardell, Jr, R R ^[1]

---

1. Univ. of Cincinnati College of Medicine, OH (USA)

The effects of short- and long-term stimulation of glycogen synthesis elicited by dexamethasone were studied by light (LM) and electron (EM) microscopic radioautography (RAG) and biochemical analysis. Adrenalectomized rats were fasted overnight and pretreated for short- (3 hr) or long-term (14 hr) periods with dexamethasone prior to intravenous injection of tracer doses of 3H-galactose. Analysis of LM-RAGs from short-term rats revealed that about equal percentages (44%) of hepatocytes became heavily or lightly labeled 1 hr after labeling. The percentage of heavily labeled cells increased slightly 6 hr after labeling, and unlabeled glycogen became apparent in some hepatocytes. The percentage of heavily labeled cells had decreased somewhat 12 hr after labeling, and more unlabeled glycogen was evident. In the long-term rats 1 hr after labeling, a higher percentage of heavily labeled cells (76%) was observed compared to short-term rats, and most glycogen was labeled. In spite of the high amount of labeling seen initially, the percentage of heavily labeled hepatocytes had decreased considerably to 55% by 12 hr after injection; and sparsely labeled and unlabeled glycogen was prevalent. The EM-RAGs of both short- and long-term rats were similar. Silver grains were associated with glycogen patches 1 hr after labeling; 12 hr after labeling, the glycogen patches had enlarged; and label, where present, was dispersed over the enlarged glycogen clumps. Analysis of DPM/mg tissue corroborated the observed decrease in label 12 hr after administration in the long-term animals. The loss of label observed 12 hr after injection in the long-term pretreated rats suggests that turnover of glycogen occurred during this interval despite the net accumulation of glycogen that was visible morphologically and evident from biochemical measurement.

• OSTI ID: 6422829
• Journal Information: American Journal of Anatomy; (USA), Vol. 188:4; ISSN 0002-9106
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
DEXAMETHASONE
BIOCHEMICAL REACTION KINETICS
GLYCOGEN
LABELLING
AUTORADIOGRAPHY
BIOSYNTHESIS
GALACTOSE
LIVER CELLS
RATS
TRITIUM COMPOUNDS
ADRENAL HORMONES
ALDEHYDES
ANIMAL CELLS
ANIMALS
CARBOHYDRATES
CORTICOSTEROIDS
GLUCOCORTICOIDS
HEXOSES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
KETONES
KINETICS
MAMMALS
MONOSACCHARIDES
ORGANIC COMPOUNDS
POLYSACCHARIDES
PREGNANES
REACTION KINETICS
RODENTS
SACCHARIDES
SOMATIC CELLS
STEROIDS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques