UNIPROT:P56851 - FACTA Search

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

Lipoprotein lipase (LPL) and hepatic lipase (HL) enzyme activities were previously reported to be regulated during development, but the underlying molecular events are unknown. In addition, little is known about LPL evolution. We cloned and sequenced a complete mouse LPL cDNA. Comparison of sequences from mouse, human, bovine, and guinea pig cDNAs indicated that the rates of evolution of mouse, human, and bovine LPL are quite low, but guinea pig LPL has evolved several times faster than the others. 32P-Labeled mouse LPL and rat HL cDNAs were used to study lipase mRNA tissue distribution and developmental regulation in the rat. Northern gel analysis revealed the presence of a single 1.87 kb HL mRNA species in liver, but not in other tissues including adrenal and ovary. A single 4.0 kb LPL mRNA species was detected in epididymal fat, heart, psoas muscle, lactating mammary gland, adrenal, lung, and ovary, but not in adult kidney, liver, intestine, or brain. Quantitative slot-blot hybridization analysis demonstrated the following relative amounts of LPL mRNA in rat tissues: adipose, 100%; heart, 94%; adrenal, 6.6%; muscle, 3.8%; lung, 3.0%; kidney, 0%; adult liver, 0%. The same quantitative analysis was used to study lipase mRNA levels during development. There was little postnatal variation in LPL mRNA in adipose tissue; maximal levels were detected at the earliest time points studied for both inguinal and epididymal fat. In heart, however, LPL mRNA was detected at low levels 6 days before birth and increased 278-fold as the animals grew to adulthood.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipoprotein lipase and hepatic lipase mRNA tissue specific expression, developmental regulation, and evolution. 272 48

Intrapancreatic activation of proteases is believed to play a major role in the pathogenesis of acute necrotizing pancreatitis. Several authors have questioned, however, the central role of trypsin in autodigestion of the pancreas. To clarify the direct effects of pancreatic enzymes and other related factors on acinar cells, we used the model of isolated pancreatic acini. Acini were prepared from male Wistar rats by collagenase digestion. Protein synthesis was measured by incubation of acini with [35S]methionine. Acini were resuspended thereafter in fresh buffer and further incubated for 30-90 min under various conditions [e.g., with pancreatic homogenates, ascites (from rats with pancreatitis induced by sodium taurocholate), pure pancreatic enzymes, and other factors]. The percentage of release of newly synthesized proteins into the culture medium was regarded as a biochemical parameter of cellular integrity. A morphologic score of cellular integrity was obtained via light microscopic evaluation of acini at the end of the various incubations by measuring the degree of cell lysis, loss of cell granules, ballooning, formation of vacuoles, and karyopyknosis. When normal [35S]methionine-labeled pancreatic acini were incubated with various factors, the percentage of release of labeled proteins into the medium was as follows: incubation with HEPES/Ringer's buffer, 1.8%; hemorrhagic pancreatic ascites, 3.8%; pancreatic homogenates, 2.0%; lipase, 1.8%; phospholipase A2, 3.0%; phospholipase A2 + lecithin, 3.2%; trypsin, 2.5%; 5% olive oil, 1.8%; ascites + olive oil, 78.3%; ascites + homogenized epididymal fat, 79.9%; lipase + olive oil, 32.0%; pancreatic homogenates + olive oil, 28.0%; diolein, 2.65%; and oleic acid, 62.9%. The cellular release of radiolabeled proteins showed an inverse correlation with cellular integrity as shown by light microscopy. We postulate that interstitial release of degradation products from triglycerides by lipase causes cellular disruption. Whereas phospholipase A2 and proteases do not seem to be very harmful in the early phases of cellular damage, lipase may play a major role in acute necrotizing pancreatitis.
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PMID:Role of pancreatic enzymes and their substrates in autodigestion of the pancreas. In vitro studies with isolated rat pancreatic acini. 291 45

4 h after intravenous injection of recombinant HuTNF-alpha to fed rats, an increase in heart, diaphragm, and plasma lipoprotein lipase activity was observed. At the same time, a 40-60% decrease in enzymic activity in epididymal fat pad and kidney and 40% decrease in hepatic lipase activity in liver had occurred. Similar results were obtained 20 h after injection of recombinant HuTNF-alpha into fasted rats. Pretreatment with Indomethacin did not affect the changes in tissue lipoprotein lipase activity observed following recombinant HuTNF-alpha administration. Serum triacylglycerol concentration increased by 2- and 6-fold; 4 and 20 h after recombinant HuTNF-alpha administration. Disappearance of 14C-labeled triacylglycerol from the circulation after injection of small chylomicrons, biosynthetically labeled in their triacylglycerol and cholesterol moieties, was lower in TNF-treated than in control rats. However, the clearance rate of triacylglycerol was the same or even higher in recombinant HuTNF-alpha treated rats (assuming that 14C-labeled chylomicron triacylglycerol represents the serum triacylglycerol pool). The livers of recombinant HuTNF-alpha-treated rats and controls contained similar amounts of 14C-labeled lipids, but less [3H]cholesterol, suggesting that in recombinant HuTNF-alpha-treated rats, the liver took up chylomicron remnant particles enriched with triacylglycerol. Separation of the d less than 1.04 g/ml fraction of serum obtained from control and recombinant HuTNF-alpha treated rats by zonal ultracentrifugation revealed that in recombinant HuTNF-alpha-treated rats the lipoprotein particles were less lipolyzed than in controls. The secretion rate of [3H]triacylglycerol into the serum was determined 90 min after injection of [3H]palmitate albumin complex and Triton WR 1339. In recombinant HuTNF-alpha-treated rats, the secretion of [3H]triacylglycerol into plasma was 48% higher than in controls. It is suggested that the increase in lipoprotein lipase activity of heart and diaphragm resulted from an indirect effect of TNF. It is concluded that the increase in serum triacylglycerol in the recombinant HuTNF-alpha-treated rats is due mainly to an increased secretion of triacylglycerol by the liver. Impaired lipolysis, probably due to a fall in hepatic lipase could also contribute to the rise in plasma triacylglycerol.
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PMID:Mechanism of the hypertriglyceridemia induced by tumor necrosis factor administration to rats. 291 56

The effect of halothane on isoproterenol-stimulated lipolysis was determined in isolated rat epididymal fat cells. The maximal lipolytic response (Emax) activated by isoproterenol was 350 +/- 61 nmol of glycerol/10(5) cells/hr with an EC50 of 5.1 X 10(-9) M. When the adipocytes were simultaneously bubbled with 2.5% halothane, the Emax decreased to 158 +/- 43 nmol of glycerol/10(5) cells/hr and the dose response curve for isoproterenol was shifted to the right (EC50 3.5 X 10(-8) M, p less than 0.05). When lipolysis was maximally stimulated with (-)-isoproterenol (10(-6)M), the inhibitory effect of halothane was found to be both dose dependent (IC50 approximately 2.5%, v/v) and reversible following washout. Neither the nonhydrolyzable cAMP analog, 8-(4-chlorophenylthio) adenosine 3',5'-cyclic monophosphate (2 X 10(-3)M), nor forskolin (10(-6) M) was able to normalize lipolysis in the presence of halothane. The activation of cAMP-dependent protein kinase (EC 2.7.1.37) activity by isoproterenol was not different in halothane-exposed cells when compared to unexposed cells. When control adipocytes were exposed to isoproterenol (10(-6) M), there was a 2.5-fold increase in the activity of hormone-sensitive lipase (EC 3.1.1.3) from 0.64 +/- 0.13 to 1.53 +/- 0.32 pkat (pmol/sec) per mg (p less than 0.005, n = 10). However, in the presence of halothane (2.5%, v/v) isoproterenol stimulation of hormone-sensitive lipase was attenuated by 50% to values of 1.06 +/- 0.23 pkat/mg (p less than 0.01, n = 10). Halothane had no direct inhibitory effect on hormone-sensitive lipase since this enzyme's activity was unaffected when homogenates of isoproterenol-stimulated control cells were incubated with halothane. These studies suggest that halothane impairs the activation of hormone-sensitive lipase by cAMP-dependent protein kinase and in this manner inhibits beta-adrenergic-stimulated lipolysis.
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PMID:Mechanism of halothane-induced inhibition of isoproterenol-stimulated lipolysis in isolated rat adipocytes. 335 97

In vitro experiments using both primary fetal hepatocyle cultures and adipoblast cultures have demonstrated that the presence of the fa gene is associated with decreased synthetic capacity, when compared to wild-type cultures. These results are in contrast to the elevated lipogensis and lipoprotein-lipase activities found in vivo in young adult obses (fafa) Zucker rats compared to their lean littermates. These studies used adipoblast cultures to address three possible explanations for these in vitro-in vivo differences: 1) FaFa and fafa adipoblast cultures represent different cell populations with intrinsically different abilities to differentiate, ie, to lipid-fill. 2) The decreased synthetic capacities in fafa vs FaFa adipoblast cultures are specific to cultures derived from the epididymal pad. 3) Cultured adipoblasts produce factor(s) that affect adipoblast differentiation in vitro. Results indicate that 1) the rate of differentiation is slower in fafa than in FaFa adipoblasts 2) there are depot-related differences in lipid metabolism, but these differences do not negate the in vitro association between the fa gene and decreased synthetic capacity and 3) FaFa epididymal-derived adipoblasts produce a factor(s) that affects inguinal-derived adipoblast differentiation and/or growth in vitro. Thus it is important to take both the site of cell origin and culture conditions into consideration when using in vitro systems as an approach to understanding complex in vivo disorders, such as obesity in the Zucker fafa rat.
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PMID:Adipoblasts from the Zucker fafa rat. 384 Jul 74

Mechanisms for hypercholesterolemia and hypertriglyceridemia and the effects of KCD-232, a new hypolipidemic agent, on them were studied in male Wistar rats with daunorubicin (DR)-induced nephrosis. Single intravenous injection of DR dose-dependently increased urinary protein loss and serum lipid levels (0,3,6 and 12 mg/kg). Twenty-four days after the injection of DR (6 mg/kg), serum cholesterol (Ch) and triglyceride (TG) levels markedly increased and free fatty acid level tended to decrease with no effects on liver lipid levels. Hepatic Ch synthesis from [14C]acetate in vitro increased by 2.1-fold, while exogenous Ch absorption slightly decreased. The clearance of intravenously injected [3H]Ch from the circulation was delayed. Hepatic fatty acid (FA) synthesis also increased by 2.7-fold, and hepatic TG lipase activity tended to decrease. KCD-232 improved the hypercholesterolemia and hypertriglyceridemia of DR-treated rats. The drug inhibited the elevated hepatic Ch synthesis and exogenous Ch absorption and thus improved the delayed Ch clearance from the circulation. KCD-232 markedly inhibited the elevated hepatic FA synthesis and stimulated both hepatic FA oxidation and lipoprotein lipase activity from the epididymal adipose tissue of the nephrotic rats. These results suggest that 1. DR-induced hypercholesterolemia is due to both an increased Ch synthesis in the liver and delayed clearance of Ch from the circulation; 2. DR-induced hypertriglyceridemia is caused by both an increased hepatic FA synthesis and depressed TG hydrolysis in the circulation; 3. KCD-232 improves the hypercholesterolemia by inhibiting the elevated Ch synthesis and Ch absorption from the gut; and 4. KCD-232 improves the hypertriglyceridemia by inhibiting the elevated hepatic FA synthesis and by stimulating both hepatic FA oxidation and TG hydrolysis activity in the circulation.
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PMID:[Experimental nephrotic hyperlipidemia induced in rats by daunorubicin and effects of KCD-232[4-(4'-chlorobenzyloxy)benzyl nicotinate] on lipid metabolism]. 402 7

1. The rise in clearing-factor lipase activity that occurs when epididymal fat bodies from starved rats are incubated in appropriate media in vitro is inhibited in the presence of 6-N-2'-O-dibutyryl-3',5'-(cyclic)-AMP (1mm). 2. Inhibition occurs at a concentration of glucose in the incubation medium of 1.3mg./ml. or less, but not at a glucose concentration of 2.4mg./ml., unless caffeine (1mm), an inhibitor of 3',5'-(cyclic)-nucleotide phosphodiesterase, is also present. Caffeine (5mm) alone inhibits the rise in clearing-factor lipase activity at a glucose concentration of 2.4mg./ml. of medium. 3. The concentration of free fatty acids in the epididymal fat bodies normally falls during incubations in vitro as the rise in clearing-factor lipase activity occurs. In the presence of 1mm-6-N-2'-O-dibutyryl-3',5'-(cyclic)-AMP, however, either the tissue free fatty acid concentration is increased or it does not fall to the same extent. The concentration of glucose in the incubation medium is important in determining the direction and extent of the changes in tissue free fatty acid concentration that occur in the presence of 6-N-2'-O-dibutyryl-3',5'-(cyclic)-AMP. 4. Free fatty acid concentrations in epididymal fat bodies in vivo rise as the clearing-factor lipase activity of the tissue falls during starvation. 5. The possibility that the concentration of 3',5'-(cyclic)-AMP in adipose tissue may regulate clearing-factor lipase activity, and that the regulation may occur through effects of the nucleotide on tissue free fatty acid concentrations, is discussed.
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PMID:Clearing-factor lipase in adipose tissue. A possible role of adenosine 3',5'-(cyclic)-monophosphate in the regulation of its activity. 430 48

1. Incubation of intact epididymal adipose tissue from fed rats at 37 degrees in an albumin solution at pH7.4 in vitro results in rapid loss of clearing-factor lipase activity until a low activity, stable to prolonged incubation, is attained. The clearing-factor lipase activity of intact tissue from starved rats, which is initially much less than that of tissue from fed rats, is mainly stable to incubation at 37 degrees . 2. Much of the clearing-factor lipase activity of intact epididymal adipose tissue from fed rats is inactivated by collagenase. The enzyme activity of intact tissue from starved rats is not inactivated by collagenase. 3. The clearing-factor lipase activity of fat cells isolated from the epididymal adipose tissue of fed rats is stable to prolonged incubation at 37 degrees . It represents only a small proportion of the total activity of the intact tissue. In starved rats, the isolated fat cells contain a much higher proportion of the activity of the intact tissue. Their activity is also stable at 37 degrees . 4. Incubation of isolated fat cells in a serum-based medium leads to a progressive rise in clearing-factor lipase activity. Actinomycin increases the extent of this rise in activity. No rise in clearing-factor lipase activity occurs when stromal-vascular cells isolated from epididymal adipose tissue are incubated in the medium. 5. The findings indicate that less than 20% of the activity of intact adipose tissue from fed rats is retained when fat cells are isolated from the tissue by collagenase treatment. The activity that is lost could be that which normally functions in the uptake of triglyceride fatty acids by the tissue.
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PMID:Clearing-factor lipase in adipose tissue. Distinction of different states of the enzyme and the possible role of the fat cell in the maintenance of tissue activity. 430 92

Brief incubation of partially purified preparations of hormone-sensitive lipase from rat epididymal fat pads with ATP, Mg(++), cyclic adenosine 3':5'-monophosphate and rabbit muscle protein kinase (phosphorylase b kinase kinase) resulted in enhancement of lipolytic activity (44-93%). Little or no activation was observed when either the cofactor mixture or the protein kinase was omitted. When the fat pads were incubated with epinephrine prior to homogenization, addition of kinase and cofactors to the soluble supernatant fraction caused no activation whereas good activation was obtained in preparations from paired fat pads not exposed to epinephrine. The results indicate that the cyclic AMP-mediated activation of hormone-sensitive lipase in adipose tissue involves a protein phosphorylation step. Whether the lipase itself is phosphorylated and thus activated or whether the protein kinase is activating a mediating enzyme, in analogy with its action in the glycogen phosphorylase system, remains to be determined.
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PMID:ATP-dependent and cyclic AMP-dependent activation of rat adipose tissue lipase by protein kinase from rabbit skeletal muscle. 431 80

Sucrose gradient centrifugation has been used to examine the triglyceride lipases present in extracts of rat epididymal adipose tissue. The aqueous infranatant recovered between the pellet and fat cake of tissue homogenates which had been centrifuged at 40,000 g was shown to contain two types of triglyceride lipase activity. One of these appears in the 15s region and has been identified as the active form of the "hormone-sensitive lipase" believed to be responsible for initiating the hydrolysis of tissue triglyceride stores in response to lipolytic stimuli. The activity of this enzyme was selectively increased in extracts prepared from tissue exposed to epinephrine and decreased in extracts of insulin-treated tissue. The increased lipolytic activity of extracts of tissue from fasted or fasted-refed rats was also found largely in this region. When the tissue was incubated with orthophosphate-(32)P, radioactivity was incorporated into a protein migrating at 15s. A second peak of triglyceride lipase activity appeared in the 6s region coincident with the location of the monoglyceride and diglyceride lipase activities. The amount of 6s triglyceride lipase activity did not correlate with changes in the lipolytic activity of the tissue from which the extracts were prepared, and its physiological function remains to be elucidated. The lipoprotein lipase and the short-chain triglyceride lipase ("tributyrinase") each moved more slowly in the gradient than the 6s triglyceride lipase. Both the 6s and 15s enzymes were shown to be present in washed adipocytes isolated from the tissue by collagenase digestion.
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PMID:Studies on the hormone-sensitive lipase of adipose tissue. 432 8

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