Hepatic glycogen synthesis in the fetal mouse: An ultrastructural, morphometric, and autoradiographic investigation of the relationship between the smooth endoplasmic reticulum and glycogen

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5545620

Breslin, J S

Fetal rodent hepatocytes undergo a rapid and significant accumulation of glycogen prior to birth. The distinct association of the smooth endoplasmic reticulum (SER) with glycogen during glycogen synthesis documented in the adult hepatocyte has not been clearly demonstrated in the fetus. The experiments described in this dissertation tested the hypothesis that SER is present and functions in the synthesis of fetal hepatic glycogen. Biochemical analysis, light microscopic (LM) histochemistry and electron microscope (EM) morphometry demonstrated that fetal hepatic glycogen synthesis began on day 15, with maximum accumulation occurring between days 17-19. Glycogen accumulation began in a small population of cells. Both the number of cells containing glycogen and the quantity of glycogen per cell increased as glycogen accumulated. Smooth endoplasmic reticulum (SER) was observed on day 14 of gestation and throughout fetal hepatic glycogen synthesis, primarily as dilated ribosome-free terminal extensions of rough endoplasmic reticulum (RER), frequently associated with glycogen. SER was in close proximity to isolated particles of glycogen and at the periphery of large compact glycogen deposits. Morphometry demonstrated that the membrane surface of SER in the average fetal hepatocyte increased as glycogen accumulated through day 18 and dropped significantly as glycogen levels peaked on day 19. Parallel alterations in RER membrane surface, indicated overall increases in ER membrane surface. Autoradiography following administration of {sup 3}H-galactose demonstrated that newly synthesized glycogen was deposited near profiles of SER at day 16 and at day 18; however, at day 18 the majority of label was uniformly distributed over glycogen remote from profiles of SER.

• Research Organization: Cincinnati Univ., OH (United States)
• OSTI ID: 5545620
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
AUTORADIOGRAPHY
BIOLOGICAL ACCUMULATION
BIOLOGICAL FUNCTIONS
BIOSYNTHESIS
BODY
CARBOHYDRATES
CELL CONSTITUENTS
DIGESTIVE SYSTEM
ELECTRON MICROSCOPY
ENDOPLASMIC RETICULUM
FETUSES
GALACTOSE
GLANDS
GLYCOGEN
HEXOSES
HYDROGEN COMPOUNDS
LIVER
MAMMALS
MICE
MICROSCOPY
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANS
POLYSACCHARIDES
RODENTS
SACCHARIDES
SYNTHESIS
TRITIUM COMPOUNDS
VERTEBRATES