text: Differential secretion of proteins and glycoproteins by livers of immature and adult rats. Effect of antimicrotubule drugs.
  This study was initiated to re-examine reported differences in the action of antimicrotubule agents on plasma protein secretion from livers of immature versus adult rats. The aim was (1) to determine the composition and to monitor the secretion of various plasma proteins and glycoproteins from liver slices labeled in vitro with specific amino acids and sugar residues, and (2) to correlate observed differences in secretion of these proteins with structural changes in the hepatocytes of the different aged animals. For the most part, slices of liver from fetal (term), neonatal (4- to 5 days old), and adult rats (70 days old) were incubated with radioactive amino acids or various tritiated sugars specific for N-linked core oligosaccharide and/or N-linked terminal oligosaccharide chains. Our findings indicate that liver slices of fetal and neonatal rats are efficient in synthesizing plasma proteins including fully glycosylated glycoproteins. The secretion of glycosylated and nonglycosylated proteins believed to be processed through Golgi complexes was inhibited to the same extent (approximately 70-80%) by antimicrotubule agents, regardless of the age of the host animal. However, other proteins and glycoproteins secreted by livers of immature rats were found to be relatively insensitive (i.e. inhibited to only 30-40%) to the action of various antimicrotubule drugs. The glycoproteins were found to lack N-linked terminal sugars (although the glycoproteins did contain N-linked core sugars), and it is likely that the drug-insensitive proteins bypassed critical glycosylating sites in the Golgi compartment prior to release. Overall, these findings support earlier data showing that antimicrotubule drugs have a special impact on Golgi-associated events in liver cells. To what extent these findings are related to the action of microtubules remains to be seen.
  
entities.text: ['livers']
entities.type: Organ
entities.entity_id: PMID-3134031_T1
entities.text: ['microtubule']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T2
entities.text: ['microtubule']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T3
entities.text: ['plasma']
entities.type: Organism_substance
entities.entity_id: PMID-3134031_T4
entities.text: ['livers']
entities.type: Organ
entities.entity_id: PMID-3134031_T5
entities.text: ['plasma']
entities.type: Organism_substance
entities.entity_id: PMID-3134031_T6
entities.text: ['liver slices']
entities.type: Multi-tissue_structure
entities.entity_id: PMID-3134031_T7
entities.text: ['hepatocytes']
entities.type: Cell
entities.entity_id: PMID-3134031_T8
entities.text: ['liver']
entities.type: Organ
entities.entity_id: PMID-3134031_T9
entities.text: ['slices']
entities.type: Multi-tissue_structure
entities.entity_id: PMID-3134031_T10
entities.text: ['fetal']
entities.type: Developing_anatomical_structure
entities.entity_id: PMID-3134031_T11
entities.text: ['liver slices']
entities.type: Multi-tissue_structure
entities.entity_id: PMID-3134031_T12
entities.text: ['fetal']
entities.type: Developing_anatomical_structure
entities.entity_id: PMID-3134031_T13
entities.text: ['plasma']
entities.type: Organism_substance
entities.entity_id: PMID-3134031_T14
entities.text: ['Golgi complexes']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T15
entities.text: ['microtubule']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T16
entities.text: ['livers']
entities.type: Organ
entities.entity_id: PMID-3134031_T17
entities.text: ['microtubule']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T18
entities.text: ['Golgi compartment']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T19
entities.text: ['microtubule']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T20
entities.text: ['Golgi']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T21
entities.text: ['liver cells']
entities.type: Cell
entities.entity_id: PMID-3134031_T22
entities.text: ['microtubules']
entities.type: Cellular_component
entities.entity_id: PMID-3134031_T23