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PubMed1980

L-Thyroxine, cortisol and diet affect the level of amylase in the parotid gland of developing rats.

The effects of cortisol (10 microgram/g body weight) and L-thyroxine (T4; 0.2 microgram/g body weight) on the activity of parotid gland amylase in young rats were investigated. Administration of cortisol or T4 for 5 consecutive days from day 5 after birth caused the precocious appearance of amylase, T4 having almost twice the effect of cortisol. Cortisol and T4 did not have synergistic effects. In thyroidectomized-adrenalectomized rats, T4 increased amylase activity but cortisol did not. The increase in enzyme activity after day 20 was much less in rats thyroidectomized on day 10 than in rats adrenalectomized on day 10. These results suggest that T4 has a direct effect on the early increase of amylase activity (days 15-25) and that the action of glucocorticoid requires the presence of endogenous thyroid hormones. The hormone-induced level of amylase in intact rats was less than that of normal adult rats. Forced weaning of intact rats resulted in a further increase in amylase activity, suggesting that further amylase accumulation (after day 25) may be due to dietary factors.

Adrenalectomy↗
PubMed1989

The relationship between free cytosolic calcium and amylase release in rat pancreatic acini.

We have studied the effects of various pancreatic secretagogues on free cytosolic calcium ([Ca2+]i) and amylase release in dispersed rat pancreatic acini, to determine the role of [Ca2+]i in stimulated enzyme secretion from the exocrine pancreas. Dispersed rat pancreatic acini were loaded with the new Ca2+-sensitive fluorescent indicator, fura-2. Resting [Ca2+]i was 110 +/- 2 nM (a mean +/- S.E.). Carbachol, caerulein, bombesin, and neuromedin B and C each caused a rapid increase in [Ca2+]i; maximal increases of 100 to 400-500 nM were reached within 20s following the secretagogue addition, and this was followed by a return to a lower sustained level within 2 min. When enzyme secretion from the acini was monitored as a function of time using a perifusion system, secretagogue-induced amylase release took a biphasic pattern consisting of an initial burst phase for a several minutes and a second sustained phase during stimulation. Although sustained amylase secretion occurred at near resting [Ca2+]i, the peak [Ca2+]i correlated with the amount of stimulated amylase release as well as with the initial release, during submaximal and maximal stimulation by these agents. At supramaximal concentrations of carbachol and caerulein, amylase release, but not the increase in [Ca2+]i, was attenuated. On the other hand, in response to supramaximal concentrations of bombesin, and neuromedin B and C, both the amount of amylase released and the peak [Ca2+]i were similar to those obtained in response to maximal concentrations. From a standpoint of time course analysis of enzyme secretion, both the first burst phase and the second sustained phase were inhibited during stimulation by 10(-3) M carbachol, compared with 10(-5) M carbachol, while supramaximal stimulation by neuromedin C caused a pattern of amylase release similar to that produced by maximal stimulation. These data suggest that in pancreatic acinar cells an increase in [Ca2+]i plays an important role in stimulus-secretion coupling; however, other factors may be indispensable in regulating enzyme secretion. Furthermore, it is suggested that there is a difference in the intracellular messenger system between carbachol and caerulein, and neurotransmitters belonging to the bombesin family, especially during supramaximal stimulations.

Amylases↗
PubMed1985

Effect of bile salt on amylase release from rat pancreatic acini.

The effect of different bile salts on amylase release from isolated rat pancreatic acini has been studied. The bile salt-stimulated discharge of amylase could be divided into three situations, depending on the concentration of bile salt. At low concentrations, between 1 and 100 X 10(-6)M, there was a slight increase in amylase secretion, 5-7% of total, which varied with the type of bile salt but was independent of the concentration of bile salt. The release of amylase stimulated by cholecystokinin, secretin, and carbachol was not affected by bile salts at this low concentration. At slightly higher concentrations, between 250 and 1000 X 10(-6)M, there was a large release of amylase, 10-40% of total, which was dependent on both type and concentration of bile salt. This release occurred specifically for amylase and was not followed by release of either membrane-bound dipeptidylpeptidase IV or intracellularly located lactic dehydrogenase. At higher concentrations, 2000-5000 X 10(-6)M, both amylase and dipeptidylpeptidase IV and lactic dehydrogenase were released, accompanying viability changes of the cells with uptake of trypan blue.

Amylases↗
PubMed1986

Effects of extracellular calcium and magnesium on bile-salt-stimulated amylase release from rat pancreatic acini.

The effects of extracellular calcium and magnesium on bile-salt-induced amylase release from rat pancreatic acini have been studied. The amylase releases caused by from 0.25 mM to 1.0 mM taurodeoxycholate (TDC) and by taurochenodeoxycholate (TCDC) at a concentration of more than 0.75 mM were reduced by ethylenediaminetetraacetic acid (EDTA) and increased by verapamil. EDTA and verapamil had no significant effect on the taurocholate (TC) (1.0-5.0 mM)-stimulated amylase release. The inhibiting effect of EDTA began to appear already during the initial 5 min and was not parallel to any change of lactate dehydrogenase release. The TDC- and TCDC-stimulated amylase release was strongly dependent on the concentrations of extracellular calcium and was only weakly dependent on extracellular magnesium. The TC-induced amylase release was slightly increased only at high concentrations of calcium and magnesium. It is suggested that the mechanism of dihydroxy bile-salt-induced amylase release from rat pancreatic acini is different from that of trihydroxy bile salt. The dihydroxy bile-salt-stimulated amylase release is dependent on extracellular calcium but does not seem to be related to the uptake of calcium by the acini.

Amylases↗
PubMed2000

Fluid and amylase secretion by perfused parotid gland: physio-morphological approach.

Whole gland perfusion technique was applied to rat parotid glands to assess whether amylase affects fluid secretion. Control perfusion without any secretagogue evoked no spontaneous secretion. Carbachol (CCh 1 microM) induced both amylase and fluid secretion with distinctive kinetics. Fluid secretion occurred constantly around 60 microL/g-min, whereas amylase secretion exhibited an initial peak, followed by a rapid decrease to reach a plateau. Isoproterenol (Isop 1 microM) alone did not induce fluid secretion although it evoked amylase secretion as measured in isolated perfused acini. Addition of Isop during CCh stimulation evoked a rapid and large rise in amylase secretion accompanied by small increase in oxygen consumption. Morphological observations carried out by HR SEM and TEM revealed exocytotic profiles following Isop stimulation. CCh stimulation alone seldom showed exocytotic profiles, suggesting a low incidence of amylase secretion during copious fluid secretion. Combined stimulation of CCh and Isop induced both vacuolation and exocytosis along intercellular canaliculi. These findings suggest that control of salivary fluid secretion is independent of the amylase secretion system induced by CCh and/or Isop.

Amylases↗
PubMed1999

Alpha-amylase functions as a salivary gland-specific self T cell epitope in patients with Sjögren's syndrome.

Analyses of T cell receptors (TCR) on T cells infiltrating labial salivary glands of patients with Sjögren's syndrome (SS) indicate that the cells expand by antigen stimulation in context of major histocompatibility complex (MHC). To elucidate the autoantigens recognized by T cells infiltrating in labial salivary glands from patients with SS, proteins derived from human salivary gland cDNA libraries were screened by West-Western method using TCR-CDR3 probe, which is antigen recognition region of TCR on T cells. 13 cDNA clones were detected as proteins binding to TCR-CDR3 region. One was a human alpha-amylase salivary precursor (AA54-407), suggesting that alpha-amylase might be a salivary gland-specific autoantigen. To examine whether alpha-amylase acts as an antigen in labial salivary glands, PBL from 11 patients with SS were incubated with 9 different synthetic amino acids of alpha-amylase or salivary alpha-amylase. SSCP analysis on TCR clearly showed that alpha-amylase reactive T cells were observed in labial salivary glands from 3 of 11 patients with SS (27%). These findings support the possibility that alpha-amylase functions as a salivary gland-specific T cell epitope and induces autoimmunity in SS.

Amino Acid Sequence↗
PubMed2000

Polyglucose dialysis solution influences serum activity of amylase and of lipase differently.

Polyglucose dialysis solution (PG-DS) decreases serum amylase activity owing to interference in the analytical method. The interference can make it difficult to diagnose pancreatitis. Our aim was to check whether, during PG-DS administration, serum lipase activity changes simultaneously with serum amylase activity, and, if so, what the reason is for the detected change. Studies were started in 14 continuous ambulatory peritoneal dialysis (CAPD) patients in whom 7.5% PG-DS was applied for the overnight exchange. In addition to standard clinical and laboratory data, serum activity of lipase and of total amylase were evaluated at 1.6 +/- 0.8 months before PG-DS introduction (period I, n = 14), after 1.2 +/- 0.6 months of PG-DS administration (period II, n = 14), after 4.4 +/- 0.8 months of PG-DS administration (period III, n = 11), after 8.8 +/- 2.2 months of PG-DS administration (period IV, n = 9), and at 2.0 +/- 0.6 months after PG-DS discontinuation (period V, n = 11). The PG-DS was also added to serum from CAPD patients with known activity of amylase and of lipase. Immediately and 3 hours after PG-DS addition, a significant decrease in total amylase activity was seen; lipase activity was unchanged. In consecutive study periods, the results (median and range) were: for lipase activity--50 U/L (12-131 U/L), 59 U/L (25-160 U/L; p < 0.05 vs period I), 73 U/L (26-158 U/L; p < 0.05 vs period I), 66 U/L (30-203 U/L; p < 0.05 vs period I), and 44 U/L (15-112 U/L); for amylase activity--81 U/L (43-249 U/L), 14 U/L (5-82 U/L; p < 0.05 vs period I and period V), 15 U/L (5-192 U/L; p < 0.05 vs period I), 15 U/L (10-93 U/L; p < 0.05 vs period I and period V), and 118 U/L (4-221 U/L). An increase in serum lipase activity over the normal range (27-65 U/L) was not accompanied by clinical symptoms of pancreatic dysfunction, but rises were simultaneously shown in blood urea nitrogen, in serum level of creatinine and of total calcium, and in calcium phosphorus product. Our results confirm PG-DS influence on amylase determinations, exclude PG-DS interference in lipase measurements, and indicate that long-term PG-DS administration influences pancreatic exocrine function at a subclinical level.

Amylases↗
PubMed1992

Simultaneous measurement of cholecystokinin-stimulated amylase release and cholecystokinin receptor binding in rat pancreatic acini.

In the past, isolated-dispersed pancreatic acini have been used to examine either cholecystokinin-stimulated amylase release or pancreatic acinar cholecystokinin receptors. We have developed and validated a method for simultaneous measurement of synthetic cholecystokinin octapeptide-stimulated (CCK8-stimulated) pancreatic amylase release and cholecystokinin receptors. After an 18-hour fast, rats were killed and their pancreatic acini isolated. Three-milliliter aliquots of acinar suspension were incubated for 60 minutes in N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-Ringer buffer containing graded doses of CCK8 and a constant amount (7 pmol/L) of iodine 125-labeled CCK8 (by the Bolton-Hunter method) ([125I]BH-CCK8). A 1 ml sample was removed from each flask for determination of amylase release, and the remaining 2 ml were used to determine cholecystokinin receptor capacities and affinities. The median effective dose for amylase release was 16 pmol/L, and release was maximal at 100 pmol/L CCK8 plus 7 pmol/L [125I]BH-CCK8, a dose that released 28% +/- 3% of total cellular amylase content. High affinity (equilibrium dissociation constant of high-affinity receptors = 58 +/- 8 pmol/L, receptor density of high-affinity receptors = 4 +/- 1 fmol/mg protein) and low affinity (equilibrium dissociation constant of low-affinity receptors = 7 +/- 2 nmol/L, receptor density of low-affinity receptors = 313 +/- 108 fmol/mg protein) cholecystokinin receptors were measured. The results demonstrate that CCK8-stimulated amylase release and cholecystokinin receptor binding in pancreatic acini can be measured concurrently and that the parameters of amylase release and cholecystokinin receptor binding are strikingly similar to those previously observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed2004

Inhibitory effects of rosmarinic acid extracts on porcine pancreatic amylase in vitro.

Porcine pancreatic alpha-amylase (PPA) was allowed to react with herbal extracts containing rosmarinic acid (RA) and purified RA. The derivatized enzyme-phytochemical mixtures obtained were characterized for residual amylase activity. These in vitro experiments showed that the amylase activity was inhibited in the presence of these phytochemicals. The extent of amylase inhibition correlated with increased concentration of RA. RA-containing oregano extracts yielded higher than expected amylase inhibition than similar amount of purified RA, suggesting that other phenolic compounds or phenolic synergies may contribute to additional amylase inhibitory activity. The significance of food-grade, plant-based amylase inhibitors for modulation of diabetes mellitus and other oxidation-linked diseases is hypothesized and discussed.

Amylases↗
PubMed2005

[Sequence analysis of alpha-amylase inhibitors genes with resistance to insects in wheat and Aegilops].

The alpha-amylase inhibitors have been proposed as possibly important weapons against pests. Thus, it is of importance to identify the specificity of them. Based on the EST data of alpha-amylase inhibitor genes that were retrieved from NCBI, BBSRC and GrainGenes, two PCR primers were designed. The coding sequences of 24 kD dimeric alpha-amylase inhibitors with resistance to insects in 17 wheat and Aegilops accessions were investigated and 17 new genes were obtained. Only one 24 kD alpha-amylase inhibitor gene was found in each diploid wheat and Aegilops accession, whereas 8 genes were characterized from one hexaploid wheat variety, indicating that the 24 kD alpha-amylase inhibitors in hexaploid wheat were encoded by multi-gene. The deduced amino acid sequences of 2 genes from common wheat and 1 gene from Ae. tauschii were the same as the sequence of the inhibitor 0.19, and the deduced amino acid sequence of another gene from common wheat was similar to the inhibitor 0.53 with only one amino acid difference. The amino acid sequences of 24 kD dimeric alpha-amylase inhibitors shared very high coherence (91.2%). These results suggest that the alpha-amylase inhibitors in 24 kD family were derived from common ancestral genes by phylogenesis.

Amino Acid Sequence↗
PubMed2006

[Molecular cloning and expression of extremely thermostable and acid-stable amylase gene in Pichia pastoris].

The gene encoding a extremely thermostable and acid-stable alpha-Amylase was amplified by PCR using hyperthermophilic archaebacterium pyrococcus furiosus genomic DNA as template. Then the gene was cloned into the vector of pPIC9K. The recombinant vector pPIC9K-amy was then transformed into E. coli DH5alpha strain. Sequencing test showed that the a-amylase gene cloned consisted of 1305 base pairs and the mature protein encoded by the gene consisted of 435 amino acids. The recombinant vector was transformed into chromosome of methylotrophic yeast Pichia pastoris GS115 strain. Regulated by the alpha-Factor, promoter of AOX1 gene and termination signal of yeast genomic, the recombinant a-Amylase was expressed and excreted out of the cells. The expression of the recombinant alpha-amylase was strictly induced by methanol. As induction time increased, the activity of amylase per milliliter medium went up accordingly. After 7 days induction, the activity of the amylase reached the max. The recombinant alpha-amylase exhibited maximal activity at 90 to approximately 100 degrees C and at pHranging from 4.5 to 5.0. The enzyme is so thermostable that after disposed at 100 degrees C for 5 hours over 60% of activity was retained.

Bacterial Proteins↗
PubMedDate not supplied

Control of amylase production and growth characteristics of Aspergillus ochraceus.

The growth and the extracellular amylase production by Aspergillus ochraceus were studied in a stationary culture medium. Maximum growth rate of this fungus was found after 5 days of incubation at 30 degrees C, but maximum amylase production was obtained after 2 days. The highest amylase production were attained with lactose, maltose, xylose and starch as carbon sources. The extracellular amylase production and mycelial growth were influenced by the concentration of starch. Other carbohydrates supported growth but did not induce amylase synthesis and glucose repressed it, indicating catabolite repression in this microorganism. The presence of both mechanisms of induction and repression suggests that at least these multiple forms of regulation are present in A. ochraceus. Of the nitrogen sources tested, casaminoacids, ammonium nitrate and sodium nitrate stimulated the highest yield of amylase. Optimal amylase production was obtained at pH 5.0, but enzyme activity was found only in the 4.0-6.0 pH range. These results were probably due to the inhibitory effect of NH4(+)-N in the culture medium.

Amylases↗
PubMed1991

[Comparison between alpha-amylase from B. amyloliquefaciens and B. licheniformis].

Two sequence-homologous alpha-amylases from B. amyloliquefaciens and B. licheniformis were studied with respect to their stability against heat denaturation and were compared with respect to common structure-stabilizing principles. The investigated alpha-amylases were isolated from culture broth of B. amyloliquefaciens and B. licheniformis. The molecular parameters (molecular weight and isoelectric point) are similar. The thermostability was determined by changes of the protein structure (changes of the fluorescence emission spectra). At pH 5.0 the thermostable alpha-amylase from B. licheniformis showed a rate of denaturation which was achieved by the thermolabile alpha-amylase from B. amyloliquefaciens at a temperature 15 degrees lower. The alpha-amylase from B. licheniformis exhibits a marked stability also at the alkaline pH-range in contrast to the alpha-amylase from B. amyloliquefaciens. From measurements in the presence of EDTA and Ca2+ follows that both enzymes are stabilized by binding of calcium ions. An analysis of preferred amino acid exchanges between the two sequence-homologous alpha-amylases showed correspondences and differences to the well-known diagram of ARGOS. Possibly an increased thermic stability can already be achieved by special amino acid exchanges without significant changes in the protein structure.

Bacillus↗
PubMed1990

Experiences with a new assay for pancreas specific alpha-amylase.

The evaluation of an enzymatic colorimetric method to measure pancreas amylase activity in serum using two monoclonal antibodies that specifically inhibit salivary amylase is described. The assay is quick, easy to perform and can be automated easily. Within-run and day-to-day precision studies gave CVs of less than or equal to 1.5 p. cent and less than or equal to 2.6 p. cent respectively. The test is linear up to 2,150 U/L. Salivary amylase activities up to 20,000 U/L did not contribute more than 2 p. cent to pancreatic amylase activity present in a serum sample. A significant interference by bilirubin is found. Reference values were established for both pancreatic and total amylase activities in serum and used for interpreting the results of pancreatic amylase and total amylase in 72 randomly selected patients. Results obtained by this method agree well with a lectin inhibition method (r = 0.9886).

Acute Disease↗
PubMed1985

[Clinical and experimental studies on serum and urine amylase levels in carcinoma of the pancreas and periampullary region].

Serum and urinary amylase level are different between in cases with carcinoma of the pancreas head and in those with carcinoma of body or tail of the pancreas. In this study the relationship between elevation in serum and urinary amylase level and the portion of obstructed pancreatic duct by tumor was analysed in cases with pancreatic carcinoma was analysed and also this was investigated in experimental model of pancreatic duct ligated dog. In patients with carcinoma of the pancreas and periampullary region, the site of obstruction of the main pancreatic duct was estimated by ERP and serum and urinary amylase level were measured. The values of serum amylase level were different according to the site of obstruction of the pancreatic duct by the tumor and in cases with highly elevated serum amylase levels the main pancreatic duct was obstructed within 5cm from the duodenal papilla. Pathology of these cases revealed pancreatic fibrosis derived from pancreatitis accompanied by tumor was closely related to serum and urinary amylase level. In pancreatic ligated dogs similar findings were observed. These data suggested that elevated serum amylase level is due to the pancreatic duct obstruction in cases with carcinoma of the periampullary duodenum.

Adult↗
PubMed1986

Dietary carbohydrate level determines the effect of long-term ethanol ingestion on rat pancreatic amylase content.

We studied the effects of long-term ethanol feeding on pancreatic amylase content in the rat. Because the level of pancreatic amylase depends on the carbohydrate content in the diet, the effects of ethanol ingestion were investigated at different levels of dietary carbohydrate, with fat providing the balance of calories. Animals were maintained on these diets for 3 weeks. In control animals, a reduction in carbohydrate from 47% to 11% of total calories lowered pancreatic amylase content by 60% (from 76.1 +/- 7 U/mg protein to 30.6 U/mg protein). However, in rats that consumed 11% of total calories as carbohydrate, long-term ethanol ingestion (36% of total calories) lowered the amylase content by a further 60% (from 30.6 U/mg protein to 11.8 U/mg protein). By contrast, when the dietary carbohydrate level was maintained at a high (40%) level, long-term ethanol ingestion slightly increased pancreatic amylase content. Pancreatic lipase was not affected by long-term ethanol ingestion at either low (6%) or high (35%) levels of fat. The reduction in the level of amylase caused by ethanol feeding with a low dietary carbohydrate intake was not associated with changes in the fasting blood levels of glucose, insulin, or glucagon. Long-term ethanol ingestion did not lead to morphologic changes in the acini or in the size, shape, or number of granules, as observed by light and electron microscopy. These results suggest that long-term ethanol ingestion has differential effects on pancreatic amylase, depending on the level of carbohydrate in the diet.

Amylases↗
PubMed1988

[Amylase-producing ovarian cancer treated with postoperative QF chemotherapy--a case report].

A case of an amylase-producing ovarian cancer in 69-year-old woman has been investigated by light and electron microscopy, as well as by amylase isozyme analysis. Serum and urinary amylase levels were found to be elevated, especially by an amylase isozyme analysis of the tumor homogenate which revealed a salivary type of cancer. The serum amylase level and its isozyme pattern returned to normal following therapy. Pathological examination revealed a serous cystadenocarcinoma. The ultrastructure of this tumor resembled that of other ovarian serous cystadenocarcinomas. No zymogen granules were recognized. Thus, a biochemical analysis of amylase isozyme was found to be a useful tumor marker for diagnosis and treatment of an amylase-producing ovarian serous neoplasm.

Amylases↗
PubMed1989

Pancreatic amylase measured in serum by use of a monoclonal antibody immunochemically immobilized to a solid phase.

We studied a method for measuring the pancreatic isoenzyme of amylase (EC 3.2.1.1) by use of a mouse monoclonal antibody against human salivary-type amylase (Clin Chem 1985;31:1283) coupled indirectly to particles of polyvinylidene fluoride via polyclonal goat anti-mouse immunoglobulin. These particles, in 200 microL of a suspension, could remove salivary amylase (activity 2200 U/L) from an equal volume of serum in 5 min. Measurement of amylase activity in the supernatant fluids from treated sera thus provided an assay of pancreatic amylase. Precision studies at three activity concentrations yielded within-run CVs of 1.6% to 1.7% (n = 25) and total CVs of 2.2% to 5.1% (20 days). Salivary amylase added to each of 10 sera was completely (99.8%, SD 1.6%) removed. The new method (y) showed the following regression statistics when compared with an electrophoretic method (x): slope = 0.989 (SD 0.019), intercept = -0.220% (SD 1.48%), SEE 4.0%, n = 51. Similar respective regression values were found for urine samples: slope = 0.934 (SD 0.053), intercept = 2.3 U/L (SD 3.2), SEE 8.4 U/L, n = 26. The following respective values were found when the new method (y) was compared with the previously described immunoprecipitation assay (x): slope = 1.02 (SD 0.02), intercept = 2.2% (SD 1.4%), SEE 3.3%, n = 23 sera. Reference intervals for pancreatic amylase activity in serum were established for three different substrates: maltotetraose, maltopentaose, and p-nitrophenylheptaoside.

Acute Disease↗