Putrescine as a comitogen of epidermal growth factor in rat liver growth

Nagoshi, Sumiko

doi:10.1016/0270-9139(94)90110-4

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…1). Furthermore, polyamines improved the survival rate of rats with an orthotopic liver transplant (Terakura et al 1995) and play an important role in growth-factor-induced DNA synthesis in cultured rat hepatocytes (Nagoshi & Fujiwara 1994;Higaki et al 1999).…”

Section: Introductionmentioning

confidence: 98%

Collagen sandwich culture affects intracellular polyamine levels of human hepatocytes

Weiss

Jahn²,

Cetto

et al. 2002

Cell Proliferation

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Extracellular matrices, like collagen layers, play an important role in preventing dedifferentiation of hepatocytes in long-term culture experiments. It has also been shown that polyamines are crucial for cell growth and liver differentiation - regeneration. Primary cultured hepatocytes with their low mitotic activity might be a valuable tool in studying the role of polyamines in differentiation. Here, our goal was to investigate whether an extracellular cell culture matrix can influence intracellular polyamine levels in human hepatocytes during long-term culture. Primary human hepatocytes were isolated from surgical tissue resections and were maintained either in single collagen (SG) or double collagen gel (DG) layer (sandwich) culture systems. Cell viability and function were examined and intracellular polyamine levels were measured using a highly sensitive high performance liquid chromatography (HPLC) method. Hepatocytes showed high viability in both culture systems used, but albumin secretion was diminished in SG cultured hepatocytes after 14 days. In general, total intracellular polyamine levels of hepatocytes decreased markedly in both SG and DG within the first days of culture, but remained constant until day 21 with a SG/DG ratio of about 1.4. Individual polyamines levels were dependent on the culture time and system, where spermine decreased and putrescine increased in both SG and DG over time (day 14), but spermidine increased only in DG. Our results suggest that polyamine levels, in particular putrescine, might be important regulators of hepatocyte specific function in vitro and therefore serve as a marker of differentiation for cultivated human hepatocytes.

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Section: Introductionmentioning

confidence: 98%

Collagen sandwich culture affects intracellular polyamine levels of human hepatocytes

Weiss

Jahn²,

Cetto

et al. 2002

Cell Proliferation

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“…Three 50-µl aliquots of the TCA extract (250 µl/dish) were added separately to 5 ml of scintillation fluid and each was counted. The remainder of the extract was neutralized and used to determine the peptide content by the Lowry method [19], using glutathione as a standard, or the carbohydrate content [14], using chondroitin B sulfate as a standard.…”

Section: Hepatocyte [ 3 H]putrescine Uptake Assaymentioning

confidence: 99%

Oligomeric hepatoproliferin disaggregates into an active monomer that was purified and forcefully dissociated into two different ionic species

Oosthuizen

Lambrechts

2006

BioFactors

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Hepatoproliferin (HPF), a liver regeneration factor, was isolated initially as an aggregated molecule (big-HPF) and was purified into two homogeneous, bioactive species of 14 kDa and 18.5 kDa. These two big-HPFs were disaggregated to completion into two monomeric forms (small-HPFs) when incubated for 10 days in 0.15 M ammonium bicarbonate at 25 degrees C. Both monomeric forms were purified to homogeneity as active entities, one with a molecular mass of 944 Da and one with a molecular mass of 1066 Da. Each of the two (35)S-labelled small-HPFs was found, by enzymic analysis, to contain a charged sulfonated saccharide, which was neutralized by a specific amine. Monomeric HPF is therefore a stable ionic complex formed between these two ionic species. So strong was the electrostatic association that small-HPF remained intact in solution and no amine was displaced by the ammonium ions of the buffer. Small-HPF remained unimpaired during purification, since all activity was retained despite alternating acidic and basic conditions. However, when small-HPF was brought into contact with either a cationic or an anionic resin, it was dissociated to completion when mixed continuously with the resin for 4 days. The ionic entity that was released had no bio-activity and was either a pure radioactively labeled saccharide or a non-labeled amine, depending on the kind of resin used. When incubated together, the separated counterions combine to regain full activity after 2 days of reassociation. However, with incubation for longer, this reassociated small-HPF formed different oligomeric HPFs by aggregation. Small-HPF is therefore a new kind of growth enhancer, consisting of an acidic sulfonated saccharide and a basic amine assembled into a stable active ionic complex that has a tendency to aggregate.

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Putrescine as a comitogen of epidermal growth factor in rat liver growth

Cited by 2 publications

References 16 publications

Collagen sandwich culture affects intracellular polyamine levels of human hepatocytes

Collagen sandwich culture affects intracellular polyamine levels of human hepatocytes

Oligomeric hepatoproliferin disaggregates into an active monomer that was purified and forcefully dissociated into two different ionic species

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