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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of insulin on the conversion of pyruvate into fatty acids in the presence and in the absence of glucose was studied in epididymal adipose tissue of the rat. 1. In adipose tissue from the normal rat, conversion of pyruvate into fatty acids is directly related to its concentration, the maximal rates occurring with 40mm- and the half-maximal rates with approx. 4mm-pyruvate. Insulin treatment did not greatly influence the maximal rates, but the half-maximal rates were at much lower pyruvate concentrations. This effect of insulin could be seen with physiological concentrations of this hormone (50-100muunits/ml). 2. In adipose tissue from acute-alloxan-diabetic and 36h-starved rats the conversion of pyruvate into fatty acids was almost zero until its concentration exceeded 3mm and then increased markedly as the concentration of pyruvate was increased. The lag phase of this S-shaped curve was decreased but not eliminated when insulin was present. This could account for the very low rates of glucose conversion into fatty acids in these metabolic states. Maximum rates of fatty acid synthesis were similar in the presence and in the absence of insulin, but only when 30-40mm-pyruvate was employed. Re-feeding of the starved rats or insulin treatment of the diabetic rats in vivo for several days restored these patterns to normal.
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PMID:Studies on the conversion of pyruvate into fatty acids in white adipose tissue. Effects of insulin, alloxan-diabetes and starvation. 513 46

1. The activities in rat tissues of 3-oxo acid CoA-transferase (the first enzyme involved in acetoacetate utilization) were found to be highest in kidney and heart. In submaxillary and adrenal glands the activities were about one-quarter of those in kidney and heart. In brain it was about one-tenth and was less in lung, spleen, skeletal muscle and epididymal fat. No activity was detectable in liver. 2. The activities of acetoacetyl-CoA thiolase were found roughly to parallel those of the transferase except for liver and adrenal glands. The high activity in the latter two tissues may be explained by additional roles of thiolase, namely, the production of acetyl-CoA from fatty acids. 3. The activities of the two enzymes in tissues of mouse, gerbil, golden hamster, guinea pig and sheep were similar to those of rat tissues. The notable exception was the low activity of the transferase and thiolase in sheep heart and brain. 4. The activities of the transferase in rat tissues did not change appreciably in starvation, alloxan-diabetes or on fat-feeding, where the rates of ketone-body utilization are increased. Thiolase activity increased in kidney and heart on fat-feeding. 5. The activity of 3-hydroxybutyrate dehydrogenase did not change in rat brain during starvation. 6. The factors controlling the rate of ketone-body utilization are discussed. It is concluded that the activities of the relevant enzymes in the adult rat do not control the variations in the rate of ketone-body utilization that occur in starvation or alloxan-diabetes. The controlling factor in these situations is the concentration of the ketone bodies in plasma and tissues.
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PMID:Activities of enzymes involved in acetoacetate utilization in adult mammalian tissues. 516 21

1. Methods are described for the extraction and assay of ATP, ADP, AMP, glucose 6-phosphate, l-glycerol 3-phosphate and citrate in rat epididymal adipose tissue incubated in vitro for 1hr. At this time of incubation rates of glucose uptake and outputs of glycerol, free fatty acids, lactate and pyruvate were shown to be constant. 2. In fat pads incubated in medium containing glucose (3mg./ml.) and albumin (20mg./ml.) the concentrations (in mmumoles/g. wet wt.) were: ATP, 70; ADP, 36; AMP, 9.0; glucose 6-phosphate, 3.0; l-glycerol 3-phosphate, 3.3; citrate, 8.1. 3. The volume of intracellular water calculated from ([(3)H]water space-[(14)C]sorbitol space), ([(14)C]urea space-inulin space) and (weight loss on drying-[(14)C]sorbitol space) was 1.4ml./100g. wet wt. of tissue. The intracellular volume was not changed by insulin, alloxan-diabetes or adrenaline. 4. When compared in terms of mumoles/ml. of intracellular water the concentration of ATP in adipose tissue was less than in heart and diaphragm muscles. The concentrations of ADP and AMP were greater both in absolute terms and relative to ATP. Insulin, alloxan-diabetes and adrenaline had no significant effects on the concentrations of the adenine nucleotides in adipose tissue. 5. The concentration of glucose 6-phosphate was increased by insulin and lowered by alloxan-diabetes and adrenaline. The concentration of l-glycerol 3-phosphate was increased by insulin, unchanged by alloxan-diabetes and lowered by adrenaline. The concentration of citrate was increased by adrenaline and alloxan-diabetes and unchanged by insulin. 6. The effect of glucose concentration in the medium on rates of glucose uptake in adipose tissue from normal rats and alloxan-diabetic rats was investigated. The K(u) of glucose uptake was 29-44mg./100ml. and the V(max.) was 0.77mg./g. wet wt. of tissue/hr. Insulin increased the V(max.) and alloxan-diabetes diminished it, but neither agent significantly altered the K(u). 7. The significance of these results in relation to control of metabolism of adipose tissue is discussed.
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PMID:Measurement of concentrations of metabolites in adipose tissue and effects of insulin, alloxan-diabetes and adrenaline. 596 39

1. Flow of carbon atoms from glucose and glycogen glucose to glyceride glycerol, glyceride fatty acids and glycerol was calculated in the perfused rat heart and incubated epididymal adipose tissue from the incorporation of (14)C from [U-(14)C]-glucose (into glyceride glycerol, glyceride fatty acids and glycerol in the medium), and from measurements of the specific activity of l-glycerol 3-phosphate, and the effects of insulin, adrenaline and alloxan-diabetes were studied. Measurements were also made of the uptake of glucose and the outputs of lactate, pyruvate and glycerol. 2. New methods are described for the measurement of radioactivity in small amounts of metabolites (glycerol, glucose 6-phosphate and fructose 6-phosphate and l-glycerol 3-phosphate) in which use has been made of alterations in charge induced by enzymic conversions to effect resolution by ion-exchange chromatography. 3. In hearts the specific activity of l-glycerol 3-phosphate was less than that of glucose in the medium but similar to that of lactate released during perfusion. Because repeated measurements of the specific activity of l-glycerol 3-phosphate was impracticable, the specific activity of lactate has been used as an indirect measurement of glycerol phosphate specific activity. 4. In fat pads, specific activity of lactate was the same as that of glucose in the medium and thus the specific activity of l-glycerol 3-phosphate was taken to be the same as that of medium glucose. 5. In hearts from alloxan-diabetic rats, despite decreased glucose uptake and l-glycerol 3-phosphate concentration, flow of carbon atoms through l-glycerol 3-phosphate to glyceride glycerol was increased about threefold. 6. In fat pads, flow of carbon atoms through l-glycerol 3-phosphate to glyceride glycerol was increased by insulin (twofold), by adrenaline in the presence of insulin (fivefold) and by diabetes in pads incubated with insulin (1.5-fold). These increases could not be correlated either with increases in glucose uptake, which was unchanged by adrenaline and decreased in diabetes, or with the concentration of l-glycerol 3-phosphate, which was decreased by adrenaline and unchanged in diabetes. 7. These results are discussed in relation to the control of glyceride synthesis in heart and adipose tissue and to the regulation of glyceride fatty acid oxidation in the perfused rat heart.
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PMID:Measurement of flow of carbon atoms from glucose and glycogen glucose to glyceride glycerol and glycerol in rat heart and epididymal adipose tissue. Effects of insulin, adrenaline and alloxan-diabetes. 604 84

The concentration of glucose in the plasma of alloxan-diabetic rats was 23.4 +/- 0.86 mM (mean +/- SEM; n = 18), and the concentration of insulin was 11.4 +/- 1.67 microU/ml (mean +/- SEM; n = 17). The weights of the ventral prostate (0.45 +/- 0.03 vs. 0.72 +/- 0.04 g) and seminal vesicles (1.23 +/- 0.06 vs. 1.84 +/- 0.08 g) were decreased compared to control values and the rats lost body weight, but the weights of the testes were not significantly different from control values (3.14 +/- 0.08 vs. 3.23 +/- 0.14 g/pair). Similar changes were seen in streptozotocin-diabetic rats. The concentration of fructose (micromoles per g fresh wt) was greater in the coagulating gland of alloxan-diabetic (19.6 +/- 1.3; n = 17) than control rats (9.1 +/- 0.7; n = 18). The production of 14CO2 from D-[U-14C]glucose by spermatozoa or seminiferous tubules from diabetic rats was decreased compared to that in controls [28 +/- 3 vs. 53 +/- 6 nmol glucose converted/10(8) spermatozoa X 30 min (n = 8) and 0.81 +/- 0.03 vs. 1.08 +/- 0.03 mumol glucose converted/g fresh wt X 30 min (n = 7)]. There was no change in the production of lactate or 3HOH from D-[2-3H] glucose, and the presence of insulin (10 mU/ml) in the incubation had little effect. Rat epididymal spermatozoa took up 2-deoxy-D-glucose by a facilitated diffusion mechanism; the Km was about 0.2 mM, with a maximum velocity of about 0.10 nmol/10(6) spermatozoa X 10 sec. Neither alloxan-diabetes nor the presence of insulin (10 mU/ml) had an appreciable effect on these parameters.
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PMID:The effect of experimentally induced diabetes on the metabolism of glucose by seminiferous tubules and epididymal spermatozoa from the rat. 623 7

Obese and lean alloxan-diabetic rats were given daily injections of insulin for 9 days. Plasma glucose and insulin concentrations were not different between the two genotypes given comparable amounts of insulin. Carcass fat and epididymal and retroperitoneal fat pad weights increased as the dose of insulin was increased. At each of four doses, fatties had larger fat cells, bigger pads, and more body fat than lean rats. Adipose lipoprotein lipase (LPL) activity per pad or per fat cell was increased by insulin. Except for the lowest dose of insulin, LPL activity was higher in obese rats than in lean rats. LPL activity per cell and cell size were highly correlated. However, when differences in cell size were corrected for, no significant effect of genotype existed. Cardiac LPL activities were different between the two genotypes only in nondiabetic rats. These results suggested that both insulin and some other genetic factors were important in elevating adipose LPL activities and thus fat deposition in obese Zucker rats.
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PMID:Adipose lipoprotein lipase in insulin-treated diabetic lean and obese Zucker rats. 704 62

Three methods of fractionation of ginseng radix (Panax ginseng C.A. MEYER) components for a survey of hypoglycemic principle in alloxan diabetic mice were conducted and three groups of hypoglycemic principle in alloxan diabetic mice were conducted and three groups of components tested; fat-soluble components, ginseng saponins and a third component with hypoglycemic activity. Pharmacological sequential trials of the fractionation yielded a most active fraction which was about 100-fold more effective than the original water-soluble extract of the ginseng radix. The ED50 value was 0.4 mg/kg in lowering the blood level of glucose in alloxan diabetic mice. It was demonstrated that some ginseng fractions inhibited epinephrine-induced transient hyperglycemia in mice, increased glycogen content in rat liver, decreased the blood level of acetone bodies in alloxan diabetic mice, and inhibited the release of free fatty acid from rat epididymal fat pad. The results showed that hypoglycemic components existed in a new component of ginseng radix which is different from saponin.
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PMID:Pharmacological sequential trials for the fractionation of components with hypoglycemic activity in alloxan diabetic mice from ginseng radix. 728 57

AH-9 is an acylhydrazine compound with hypoglycemic effects in normal mice, alloxan-induced diabetic mice and spontaneously diabetic KK mice. In terms of equi-molar doses (0.3 mmol/kg po), AH-9 was found to be more potent than phenfornin and glicalazide (diamicron) in normal mice. Insulin resistance was shown to be improved in spontaneously diabetic KK mice and hydrocortisone-induced insulin resistant mice after treatment with AH-9. The LD 50 of AH-9 given orally to mice was found to be 956 mg/kg (about 18 times its effective dose). Studies on the hypoglycemic mechanism of AH-9 (insulin release, insulin receptor and post-receptor) showed that AH-9 did not influence serum insulin levels in mice. But, in in vivo experiments, AH-9 appeared to promote the capacity and affinity of insulin receptors in mouse liver plasma membranes. AH-9 was also found to antagonize the elevation of blood glucose level and liver glycogen content caused by alanine injection. AH-9 was shown to enhance the conversion of U-14C-glucose to 14CO2 in mouse epididymal fat tissue in vitro. According to the above results, the hypoglycemic action of AH-9 might be due to: 1) increasing the capacity and affinity of insulin receptors; 2) directly enhancing glucose aerobic oxidation; and 3) inhibiting gluconeogenesis.
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PMID:[The hypoglycemic effect of AH-9]. 816 1

Morphological changes associated with mobilization of lipid were studied in epididymal adipose tissue from fasted and from alloxan diabetic rats. In both groups of animals a decrease in lipid content was accompanied by the formation of complex frond-like cytoplasmic processes and of loops and folds of basement membrane which extended from cell surfaces. These changes, evident after 1 day of fasting, increased in magnitude with increasing weight loss. As the lipid content of the cell decreased further, lipid-cytoplasmic interfaces became irregular and convoluted. Cytoplasmic microvesicles were prominent and appeared to be greatly increased in number. Rosette-like structures composed of microvesicles were observed in both lipid-depleted fat cells and endothelium. The interpretation of these changes and their physiological significance are discussed in terms of the physical and chemical properties of lipids and lipid metabolism. It is postulated that microvesicles may represent the mechanism of transport of free fatty acids in fat cells and in endothelium. Hypotheses are proposed and illustrated schematically for the mode of formation of microvesicular rosettes, for the mobilization and uptake of lipids by fat cells, and for the transport of lipids through endothelium.
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PMID:ADIPOSE TISSUE. MORPHOLOGICAL CHANGES ASSOCIATED WITH LIPID MOBILIZATION. 1410 16

The concentrations of the oxidized and reduced forms of the nicotinamide nucleotides were measured in the epididymal fat pads of normal, alloxan-diabetic and hypophysectomized rats. In both alloxan-diabetic rats and hypophysectomized rats the weight of the adipose tissue fell, as did the total content of NADH and NADPH; in addition, NAD(+) was decreased in the alloxan-diabetic group. Of these changes the most marked was in NADPH and this was the only significant difference when the results were expressed as nicotinamide nucleotides/mg. of tissue protein. The concentration of NADPH in the hypophysectomized rats was not altered by treatment with growth hormone but was restored to normal by treatment with thyroxine. These results are discussed in relation to the known effect of these hormonal conditions on lipid synthesis in adipose tissue.
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PMID:Influence of hormones on the nicotinamide nucleotide coenzymes of adipose tissue. 1674 25


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