Efecto de la concanavalina a sobre la actividad de las enzimas a-amilasa pancreática y tripsina en pollos de engorde / The effect of concanavalin a on pancreatic amylase and trypsin activity in broiler chickens

Con el propósito de determinar el efecto de la Concanavalina A (Con A) sobre la actividad de las enzimas a-amilasa pancreática y tripsina en pollos de engorde de 3 y 6 semanas de edad, se realizaron dos experimentos bajo condiciones in vitro. En el primero, la actividad de la enzima a-amilasa pancreática fue determinada en muestras de mucosa duodenal, para lo cual se diseñaron 5 tratamientos: ausencia de Con A (T0), presencia de Con A (T1), Con A preincubada durante 30 minutos con la enzima (T2) o con el sustrato (T3) y Caseína (T4). En el segundo experimento se evaluó el efecto de la Con A sobre la actividad de la tripsina en homogenados de páncreas, aplicando 2 tratamientos: presencia de Con A (T0) y ausencia de Con A (T1). La Con A se utilizó a una concentración semejante a la del sustrato correspondiente para cada enzima. Los resultados fueron analizados a través del Análisis de Varianza de Kruskal-Wallis. La Con A inhibió significativamente la actividad específica de la enzima a-amilasa pancreática, tanto en la tercera como en la sexta semana de edad. No hubo diferencia en la actividad de la enzima entre semanas. La preincubación de la lectina con la enzima afectó significativamente la actividad de la a-amilasa pancreática. No hubo efecto de la preincubación de la lectina con el sustrato. La tripsina no fue inhibida por la Con A bajo las condiciones del ensayo, posiblemente asociado al efecto inhibitorio de la actividad biológica que ejerce la caseína sobre la Con A.

Two trials were conducted to assess the effect of Concanavalin A on pancreatic a-amylase and trypsin activity in broiler chickens (3 and 6 week old). Pancreatic a-amylase activity was determined in mucous duodenal, applying 5 treatments: Control (without Con A, T0), Con A (T1), Con A preincubated during 30 minutes with enzyme (T2), Con A preincubated during 30 minutes with substrate (T3) and Casein (T4). In the second experiment, the effect of Con A on trypsin activity was studied in pancreas homogenate, applying 2 treatments: Control (without Con A, T0) and Con A (T1). The Con A was used in a similar concentration to corresponding substrate for each enzyme. The results were analyzed through Kruskal-Wallis. The Con A significantly inhibited specific activity of pancreatic a-amylase during the third and sixth week of age. There was no difference in the activity of the enzyme between weeks. The preincubation of lectin with enzyme significantly affected pancreatic a-amylase. There was not effect of preincubation of lectin with substrate. Trypsin was not inhibited by Con A under experimental conditions, possibly due to inhibitory effect of biological activity that exerts the casein on Con A.

Evaluation of the Clinical Usefulness for Pancreatic Amylase in Acute Pancreatitis / 대한진단검사의학회지

BACKGROUND: Recently, a new EIA method for pancreatic amylase was introduced that was assayed by inhibition of the salivary amylase using the synergistic action of two monoclonal antibodies. We evaluated the clinical usefulness of the pancreatic amylase by using the sensitivity, the specificity and diagnostic accuracy of the receiver-operator characteristics (ROC) curve. METHODS: We divided into 3 groups: acute pancreatitis (n=26) diagnosed by ultrasonography and computed tomography, control patients (n=105), and healthy controls (n=95). Serum total amylase, pancreatic amylase, and lipase were assayed by the Hitachi 7170. The upper limit of the reference range of the total amylase, pancreatic amylase, and lipase was respectively 216 U/L, 115 U/L and 200 U/L in this hospital. RESULTS: The sensitivity of total amylase, pancreatic amylase, and lipase for the diagnosis of acute pancreatitis was 73.1%, 88.5%, and 92.3%, respectively. The specificity of total amylase, pancreatic amylase, and lipase was 70.5%, 81.9%, and 82.9%, respectively. The diagnostic accuracy, determined as the area under the curve, was 0.795 for total amylase, 0.868 for pancreatic amylase, and 0.886 for lipase. There was a significant difference between the total amylase and pancreatic amylase (P=0.045), but not a significant difference between the pancreatic amylase and lipase (P=0.613) by ROC curve. CONCLUSIONS: Pancreatic amylase had a higher sensitivity, specificity, and diagnostic accuracy than the total amylase, and showed a similar diagnostic performance as lipase. Therefore, we concluded that the pancreatic amylase was a better diagnostic tool than the total amylase in the diagnosis of acute pancreatitis.

Effects of p-chlorophenylalanine on the synthesis of pancreatic amylase in rats

Previously, we have reported that p-chlorophenylalanine (PCPA), a serotonin depletor, profoundly increased pancreatic fluid and bicarbonate secretion but remarkably inhibited pancreatic amylase secretion in anesthetized rats. The present study was performed to verify the detailed effects of PCPA on pancreatic amylase synthesis that is directly related to amylase exocrine secretion. PCPA significantly decreased pancreatic RNA and protein contents as well as the amylase activity. However, pancreatic DNA content, trypsin and chymotrypsin activities were not influenced by the treatment of PCPA. The rate of pancreatic amylase synthesis, which was assessed by the amount of incorporated (35S)-methionine into amylase for 1 h, was also significantly decreased by 44% in PCPA-treated rats. In order to determine whether the PCPA-induced decrease of amylase synthesis resulted from change in the level of amylase mRNA, Northern blot analysis was performed. The mRNA expression level of amylase was also decreased by 48% in the PCPA-treated rats, indicating that the inhibitory effect of PCPA on the synthesis of pancreatic amylase was mainly regulated at a step prior to translation. It was also revealed in SDS-polyacrylamide gel electrophoresis that the qualitative change of amylase was induced by PCPA. The 54 KDa amylase band seems to be degraded into small molecular weight protein bands in PCPA-treated rats, suggesting that the PCPA-induced decrease of amylase may be partly attributed to the degradation of synthesized amylase.

Purification and properties of an α-amylase inhibitor specific for human pancreatic amylase from proso (Panicium miliaceum) seeds.

An α-amylase inhibitor was purified to homogeneity by acid extraction, ammonium sulphate fractionation, chromatography on carboxymethyl-cellulose, diethylaminoethylcellulose and Sephadex G-100 from proso grains (Panicium miliaceum). The calculated molecular weight was 14000. The inhibitor was fairly heat stable and stable under acidic and neutral conditions. The factor was more effective by two orders of magnitude in its action on human pancreatic amylase than on human salivary amylase. It did not inhibit on A. oryzae, B. subtilis and porcine pancreatic amylases. Pepsin rapidly inactivated the inhibitor. Chemical modification studies revealed that amino and guanido groups are essential for the action of the inhibitor. The inhibitor was found to protect both human salivary and pancreatic amylases against inactivation by acid. The mode of inhibition was found to be uncompetitive.