Changes in the morphology and phosphatase cytochemistry of the Golgi region of hepatocytes during the acute phase response to inflammation.
BACKGROUND
During the acute phase response to inflammation, the Golgi apparatus of rat hepatocytes processes an increased quantity of glycoproteins, in the form of acute phase reactants.


METHODS
The compartmental organization of the hepatocyte Golgi of control and 24 hour inflamed rats was studied, using transmission electron microscopic techniques, including cytochemistry, to detect nicotinamide adenine dinucleotide phosphatase (NADPase), thiamine pyrophosphatase (TPPase), and cytidine monophosphatase (CMPase) activity.


RESULTS
In inflamed rats, individual Golgi stacks were enlarged, but retained their organization into four compartments: 1) a phosphatase negative, perforated cis-element, 2) two mid-saccules which sometimes were positive for NADPase, 3) one or occasionally two NADPase and TPPase positive trans-saccules, and 4) a tubulovesicular trans-Golgi network (TGN) which was NADPase reactive and contained a spotty TPPase reaction product. Two of these compartments were noticeably altered in response to inflammation. The two mid-saccules were consistently and uniformly dilated. The TGN was altered to the point of being difficult to recognize and had acquired CMPase reactivity. In control rats the TGN consisted of anastomosing tubules forming cage-like structures; secretory granules containing lipoprotein particles pinched off from these. In inflamed rats, most of the cage-like TGN structures had been replaced with an extensive vesicular syncytium which produced secretory granules with a granulofilamentous content.


CONCLUSIONS
In hepatocytes from inflamed rats an apparent switch had occurred in the type of secretory material processed by the Golgi apparatus. Furthermore, the inflammation-induced increase in the size of individual Golgi stacks apparently was not due to a parallel increase in size of all Golgi saccules. Rather, saccules within given Golgi compartments responded in a characteristic and specific manner to the increase in glycoprotein processing that occurs during inflammation.
Thorne-Tjomsland
G
G
Department of Chemistry, University of Manitoba, Winnipeg, Canada.
Jamieson
J C
JC
D000210:Acute-Phase Reaction / Q000201:enzymology / Q000473:pathology*; D000818:Animals; D006056:Golgi Apparatus / Q000201:enzymology / Q000473:pathology*; D006651:Histocytochemistry; D066298:In Vitro Techniques; D008107:Liver Diseases / Q000201:enzymology / Q000473:pathology*; D008247:Lysosomes / Q000201:enzymology / Q000473:pathology*; D008297:Male; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D051381:Rats
D010744:Phosphoric Monoester Hydrolases