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J Dich

Publications and source records attributed to J Dich.

At least 55 records · Page 3Linked to original sources
PubMed1981

Effect of highly purified porcine gut glucagon-like immunoreactivity (glicentin) on glucose release from isolated rat hepatocytes.

We studied the effect of the highly purified gut peptide glicentin on the glucose production and cyclic AMP accumulation of isolated rat hepatocytes. Glicentin at 2.10(-7) mol/l had the same effect on glucose production as maximally effective concentrations of glucagon, but did not stimulate cyclic AMP to the same extent; furthermore, glicentin apparently had only 1/100 of the potency of glucagon on glucose production. During incubation with hepatocytes glicentin was degraded to low molecular weight fragments one of which were chromatographically very similar to fragments of glucagon. It is suggested that glicentin exerts its glucagon-like effects on hepatocytes only after degradation to glucagon-like fragments. The results also demonstrate that the coupling between cyclic AMP accumulation and glucose production depends on the nature of the stimulatory peptide.

Animals↗
PubMed1980

Fractionation and characterization of rat hepatocytes isolated from ethanol-induced fatty liver.

A procedure for fractionation of hepatocytes according to density is presented. Hepatocytes were prepared from rats fed an ethanol-containing liquid diet, a liquid diet without ethanol, or a chow diet. The hepatocytes were fractionated in a Metrizamide density gradient and the cell fractions obtained were characterized with respect to protein synthesis, fatty acid oxidation, and esterification and ATP content. From ethanol-fed rats, two fractions of hepatocytes were obtained, one with a density of approximately 1.04 gm. per ml. and one with a density of ca. 1.08 gm. per ml. Cells from the lighter fraction contained 3 times more triacylglycerol than cells from the heavier fraction. Fifty per cent of the cells from the lighter fraction contained large (greater than 5 micron) lipid droplets as compared to 6% in the heavier fraction. The average yield from a 170-gm. rat of lipid-rich and lipid-poor cells was about 65 x 10(6) and 170 x 10(6) cells, respectively. Electron micrographs of the liver before perfusion and of the isolated and washed cell fraction revealed intact ultrastructure. Fractionation of hepatocyte suspensions from rats fed a high fat liquid diet without ethanol or a chow diet normally yielded two cell fractions with densities of ca. 1.08 and 1.10 gm. per ml. and 1.10 and 1.12 gm. per ml., respectively. The metabolic capacity of the cell fractions was unaltered by the fractionation procedure as judged by the ATP content, the rate of palmitate oxidation and esterification, and the rate of protein synthesis.

Adenosine Triphosphate↗
PubMed1978

The use of food additives in Sweden.

Recently it was demonstrated that the levels of some added colours in food sold in Sweden were such that the recommended daily intake (ADI) could easily be exceeded by the consumer (Ahlborg et al. Vår Föda, 26, 1974, 194-217). New regulations concerning the use of food colours in Sweden came into force on July 1st, 1975. The collection of information on the use of food additives in products sold on the Swedish market has not been extended to cover other food additives such as preservatives and antioxidants. This study is based upon details of about 10,000 food products containing food additives. The material is being computerised and work on the evaluation is in progress. The new investigation demonstrates that the use of food colours has decreased and that very few products now contain high levels of food colours. Data will be presented concerning the levels and total amounts of preservatives, antioxidants and other food additives used in different groups of food products.

Food Additives↗
PubMed1976

Effect of glucagon on cyclic AMP, albumin metabolism and incorporation of 14C-leucine into proteins in isolated parenchymal rat liver cells.

Parenchymal rat liver cells were isolated by the collagenase method and incubated in Krebs-Henseleit buffer containing 0.5% gelatin. The basal level of cyclic AMP in isolated cells was 0.52 nmol per g liver wet wt. Glucagon (10(-10)-10(-6) M) caused a significant increase in the level of cyclic AMP. Maximum levels were obtained 2-15 min after addition of glucagon. Repeated administration of glucagon caused a new increase in cyclic AMP, but the response was lesser than after the first addition of glucagon, indicating refractoriness to glucagon. The rate of albumin secretion was 4.6 mug/min per g liver wet wt. This is about the rate found in the perfused liver, Glucagon (10(-8-10(-6) M) inhibited albumin secretion and the incorporation of 14C-leucine into albumin, into total proteins in the medium and into total proteins in the cell suspension. The effect of glucagon on albumin secretion is compatible with an effect on the rate of synthesis. A positive correlation existed between the maximal level of cyclic AMP after glucagon administration and the inhibition of both albumin secretion and the incorporation of 149leucine.

Albumins↗
PubMed1975

Effect of insulin on albumin production and incorporation of 14C-leucine into proteins in isolated parenchymal liver cells from normal rats.

Parenchymal rat liver cells were isolated by a modification of the collagenase method of Quistorff, Bondesen and Grunnet. The cells secreted albumin into the medium and incorporated 14C-leucine both into cell proteins and proteins secreted into the medium. Albumin production measured from the immunologically determined increment in the incubation medium was 1.7 +/- 0.2 mug albumin/min per g liver wet wt. This is about 30% of the rate of production in the perfused liver. Addition of insulin (10(-6)-10(-10) M) enhanced albumin production (50-17%), and incorporation of 14C-leucine both into albumin (50-8%), secreted proteins (40-9%) and cell proteins (20-8%). Insulin does not increase the production of albumin by depleting the cells. The effect of insulin on albumin production is compatible with an effect on the rate of synthesis as the specific activity of albumin is unaffected by addition of insulin.

Albumins↗
PubMedDate not supplied

Long-term culture of hepatocytes: effect of hormones on enzyme activities and metabolic capacity.

(i) Hepatocytes isolated from adult rats were cultured for 2 to 3 weeks on collagen in a modified, serum-free Waymouth medium containing fatty acids and varying concentrations of glucocorticoid, insulin and glucagon. (ii) In the presence of all three hormones, it was possible to maintain the content of DNA, the activity of glucokinase, pyruvate kinase, hexokinase and lactate dehydrogenase at initial levels for 2 to 3 weeks. The activity of glucokinase and pyruvate kinase was affected by the concentration of insulin. (iii) The activity of alcohol dehydrogenase was stable for 3 days and declined to about 25% of the initial level after 2 weeks of culture, irrespective of the presence of hormones. (iv) Maintenance of albumin secretion was dependent on the presence of glucocorticoid, and glucocorticoid and insulin showed an additive or, at some time points, a synergistic effect on its secretion. (v) The content of cytochrome P-450 could be kept at 65% of the initial level, provided that a relatively high concentration of dexamethasone was present (10(-6) M). (vi) In the absence of hormones, urea synthesis was 70% of initial levels throughout the experimental period. With insulin and glucocorticoid present, a high concentration of glucagon (10(-8) M) was required to maintain the synthesis of urea at this level. (vii) It is concluded that hepatocyte cultures as described in the present study may be a useful, well-defined system for long-term metabolic, pharmacologic and toxicologic studies.

Alcohol Dehydrogenase↗
PubMedDate not supplied

Effect of ethanol on fatty acid metabolism in cultured hepatocytes: dependency on incubation time and fatty acid concentration.

In a previous report it was shown that ethanol increases the rate of accumulation of triacylglycerol by 90% in hepatocytes in primary culture. This represents the first known suitable model for in vitro studies of the ethanol-induced fatty liver. The biochemical alterations causing this accumulation of triacylglycerol remain to be elucidated, however. In the present report it is shown that (1) the effect of ethanol exhibits a time lag of 6-9 hours (2) the increment in the content of triacylglycerol caused by ethanol is increased by increased concentrations of fatty acids (3) the fatty acid uptake is not affected by ethanol (4) fatty acid synthesis is inhibited 20% by ethanol (5) the contents of diacylglycerol and phospholipids are not affected by ethanol (6) addition of ethanol increases the cytosolic and mitochondrial redox levels. It is concluded that ethanol is likely to exert its effect on the accumulation of triacylglycerol by redistributing fatty acids between oxidation and triacylglycerol synthesis and/or between storage and secretion of triacylglycerol.

Animals↗