Albumin synthesis by liver parenchymal cells isolated from young, adult and old rats

Bezooijen, C.F.A. van; Grell, Tsehai A.J.; Knook, D.L.

doi:10.1016/0006-291x(76)90817-2

Cited by 53 publications

(10 citation statements)

References 16 publications

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“…Similar time-intervals have been reported for this process earlier ( 17,21). The initial lag-phase probably corresponds to the time needed for the synthesis and intracellular transport of secretory proteins in liver cells.…”

Section: Electron Microscopysupporting

confidence: 81%

The Effect of D‐galactosamine on Lcat Secretion and Ultrastructure of Isolated Rat Hepatocytes

Nordby

Schreiner

Berg

et al. 1977

Acta Pathologica Microbiologica Scandinavica Section A Patholog

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The effect of D-galactosamine on LCAT secmtion and ultrastructure of isolated rat hepatocytes. Acta path. microbiol. scand. Sect. A, 85: [839][840][841][842][843][844][845][846][847][848][849] 1977.The effect of D-galactosamine on secretory activity and morphology of isolated rat hepatocytes was investigated: Galactmamine was found to reduce the secretion of lipoproteins (as indicated by the release of free cholesterol and triacylglycerol) as well as the secretion of lecithin: cholesterol acyltransferase (LCAT) and [14C] -labelled proteins from the isolated cells. The secretion of LCAT was inhibited much more than that of the other secretory products studied. Transmission electron microscopy revealed that galactosamine induced morphological changes in RER, mitochondria and nucleoli. The most striking feature of galactommine-treated hepatocytes, however, was the appearance of swollen lysosomes. Some of these organelles measured up to 3 ppm in diameter. Uridine did not abolish the effect of galactosamine upon the secretory activity of hepatocytes. The most oonspicuous ultrastructural feature in cells that had been incubated with both uridine and galactmamine was the appearance of large amounts of glycogen, The possibility that galactoramine inhibits glycogenolysis is discussed. The rather selective effect of galactosamim on LCAT secretion suggests the use of this compound for the study of the interrelationship between LCAT and lipoprotein secretion.

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Section: Electron Microscopysupporting

confidence: 81%

The Effect of D‐galactosamine on Lcat Secretion and Ultrastructure of Isolated Rat Hepatocytes

Nordby

Schreiner

Berg

et al. 1977

Acta Pathologica Microbiologica Scandinavica Section A Patholog

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“…Beauchene et al (1970) suggested that the increase in protein synthesis in old animals may be a compensation by the liver for increased proteinuria. However, for the female and male WAG/Rij and female BN/Bi rats, the amount of protein excreted via the urine remained unchanged in the age period in which the sharp increase in albumin (van Bezooijen et al, 1976) and total protein synthesis (van Bezooijen et al, 1977(van Bezooijen et al, , 1981 occurred. Moreover, kidney diseases described for Marshall 520 and Wistar rats were rarely present in aging WAG/Rij and BN/Bi rats (van Bezooijen et al, 1981).…”

Section: (B) Isolated Hepatocytes In Culturementioning

confidence: 93%

“…Isolated hepatocytes in culture may resemble metabolically liver parenchymal cells in vivo (Seglen, 1976;La Breque & Howard, 1976). Immunological tests (van Bezooijen, Grell & Knook, 1976) showed that albumin synthesis by isolated rat hepatocytes approaches that of liver in vivo. Artifacts, as in other in oitro systems (fibroblasts: Schneider & Mitsui, 1976), are avoided.…”

Section: (B) Isolated Hepatocytes In Culturementioning

confidence: 99%

Protein Synthesis and Degradation During Aging and Senescence

Makrides

1983

Biological Reviews

171

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Summary 1. The published results on protein synthesis during aging are contradictory. Possible sources of error and variability include: an insufficient number of different animal ages used; use of whole organs that are cytologically highly heterogeneous; different animal strains; neglecting to measure the specific activity of the precursor pool for protein synthesis; and inadequate methodology for measurement of in vivo rates of protein synthesis. 2. In general, protein synthesis rates in mammals have been reported to decline 4–70% with age. In insects and other organisms, greater losses (60–90%) have been observed. 3. Limited evidence indicates that in some systems a decline in the rate of protein synthesis may be due to alterations (as yet of unknown nature) in the initiation components of the protein synthetic apparatus. Futhermore, some studies suggest that in some organisms aging affects the expression of specific parts of the genome. 4. The significance of results on protein metabolism obtained from some studies with nematodes is at present unknown, owing to problems associated with age‐synchronization methods. Also, the in vitro fibroblast system for the study of human cellular aging has not been met with universal acceptance; it is generally believed that this system has not yet been established as a valid analogy to mammalian aging in vivo. 5. Failure to detect defective enzymes in many old organisms indicates at least that not all proteins are altered during aging. The complete thermal stability of purified enzymes from old organisms suggests that the observed thermolability of the same enzymes in crude cell extracts is not an intrinsic property of those enzymes. Post‐translational modifications (partial denaturation) may constitute the primary mechanism for the production of altered cell polypeptides during aging. 6. The available evidence does not support the concept of an age‐dependent decline in translational accuracy. The future purification to absolute homogeneity of an altered enzyme and its ‘young’ (unaltered) counterpart, and their sequencing, should resolve the question of translational errors. 7. Some degree of age‐related ribosome loss appears to occur in fixed postmitotic cells. In general, the published polyribosomal profiles may represent artefacts due to insufficiently suppressed ribonuclease activity during extraction. 8. The published studies on protein degradation during aging are also contradictory. Some investigators have neglected the possibility of reutilization of labelled amino acid. It is possible that some of the observed age‐related alterations in protein degradation rates are due to altered endocrine status of the animals used, rather than to defects in the protein degradative pathways. The studies utilizing cell culture systems are also contradictory, probably due to different experimental designs. 9. Limited evidence suggests that protein degradation may slow down with age in mammals and nematodes. An inefficient protein degradation system in old organisms could provide a...

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“…1). In contrast, a sharp increase was found between 24 and 36 months (34). As a second liver-specific function, the synthesis of specific proteins can be mentioned.…”

Section: Aging and Cellular Division Capacitymentioning

confidence: 92%

“…A sharp decrease in the amount of BSP stored by the hepatocytes was observed between 3 and 12 months of age; this was followed by a less pronounced decline up to 36 months (Fig. Hepatocytes isolated from 3-month-old female WAG/Rij rats synthesized 5.8 p g albumin/hr/106 cells (34), which nearly equals the amount synthesized in an in vivo situation (35). These data strongly suggest that the observed decrease in the capacity of the liver to remove BSP from the blood is at least partly due to an age-related decline in the BSP storage capacity of the individual hepatocytes.…”

Section: Aging and Cellular Division Capacitymentioning

confidence: 95%

The Isolated Hepatocyte: A Cellular Model for Aging Studies

Knook

1980

Experimental Biology and Medicine

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~~ ~~Ahstruct. Based on the concept that the absence of cell division leads to senescence and that aging changes are most clearly manifest in long-lived postmitotic cells, isolated hepatocytes are proposed as a suitable model for the study of cellular aging. These cells, aged in vivo under normal physiological conditions, will be of the same age as the donor after isolation. Several possibilities and advantages of this system are discussed. Examples given of the use of isolated hepatocytes for aging studies include the investigation of the relation between age-related alterations in rat liver functions (drug clearance, albumin synthesis) and aging processes at the cellular level. The potential use of isolated hepatocytes for studies on basic cellular aspects of aging is illustrated by experiments on changes in the activities of lysosomal enzymes as well as their multiple forms. A new additional approach to the study of cell aging, particularly with regard to phenomena such as cell contacts, cell recognition, and mutual influences between cells of various types, is offered by the possibility of cocultivating hepatocytes and sinusoidal cells from young and old rat livers. 170

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Albumin synthesis by liver parenchymal cells isolated from young, adult and old rats

Cited by 53 publications

References 16 publications

The Effect of D‐galactosamine on Lcat Secretion and Ultrastructure of Isolated Rat Hepatocytes

The Effect of D‐galactosamine on Lcat Secretion and Ultrastructure of Isolated Rat Hepatocytes

Protein Synthesis and Degradation During Aging and Senescence

The Isolated Hepatocyte: A Cellular Model for Aging Studies

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