Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The food intake, pancreas weight and trypsin (EC 3.4.21.4) and alpha-chymotrypsin (EC 3.4.21.1) activities in the pancreas were measured in rats during pregnancy and lactation and after the young were weaned. 2. All the quantities measured increased significantly during lactation and had returned to their original values by 4 weeks after weaning. Food intake and pancreas weight were highest after the second week of lactation. Total trypsin and alpha-chymotrypsin activity, and the activity per g tissue, fell during pregnancy and rose during lactation, reaching a maximum 1 week after weaning. 3. From these and other results it is suggested that the hypertrophy and hypersecretion of pregnancy and lactation are initiated by changes insulin secretion and mediated by the trophic effects of gut hormones, and that differences in the nature and timing of the response may be controlled by nutrient availability.
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PMID:The effects of pregnancy and lactation on the activities of trypsin and alpha-chymotrypsin in the rat pancreas. 46 45

Insulin encapsulated in liposomes of various lipid compositions were prepared. The amount of insulin trapped in these liposomes increased in the order, negatively charged liposomes less than neutral liposomes less than positively charged liposomes. In positively charged liposomes, the amount of insulin trapped increased with increase in the amount of amphiphile stearylamine. Under the conditions tested, the highest insulin content (about 50%) was obtained with liposomes composed of phosphatidyl choline/cholesterol/stearylamine in a molar ratio of 7/2/2.25. These liposomes were stable on incubation for 3 hr at 37 degrees C in solutions of pepsin, trypsin, and pancreatin, and after these incubations, a considerable amount of insulin was still associated with the liposomes. However, the liposomes released almost all the insulin into the medium on treatment with bile. When the liposomes were administered orally to rats in the 3rd phase of acute alloxan diabetes, reduction of the blood glucose level was observed in 7 of 11 animals, the reduction persisted for several hours and was ranging from 30 to 75%. In alloxan diabetic rats showing hyperglycemia for 3 to 6 months, the liposomes also increased the glucose tolerance in half the animals tested.
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PMID:Effects of oral administration of positively charged insulin liposomes on alloxan diabetic rats: preliminary study. 47 21

The effect of insulin, glutathione, trypsin and somatotropin on processes of distribution and elimination of rifamycin SV were investigated using pharmacokinetic analysis. It was found that the peptides, especially glutathione and trypsin, enhance the distribution of rifamycin in rabbits and cause an increase of amount of this antibiotic in the central compartment.
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PMID:Effect of some peptides on distribution of rifamycin SV in rabbits. 48 68

Previous studies have shown that initiation of proliferation of density-inhibited fibroblasts by fresh serum is accompanied by a rapid increase in phosphate uptake. This increase might be a key event in the initiation of DNA synthesis. The present studies examined this possibility. Mouse 3T3, secondary chick embryo, or human diploid foreskin cultures were grown to quiescence in medium containing varying levels of serum. When proliferation of the cultures was initiated by addition of fresh serum, the changes in phosphate uptake were inversely related to the final increases in cell number. Additional experiments showed that the change in phosphate uptake following serum addition was determined by the level of phosphate uptake prior to serum addition. Addition of dexamethasone to quiescent 3T3 cultures caused them to proliferate but did not increase phosphate uptake. Similarly, trypsin or insulin stimulated proliferation of quiescent secondary chick embryo cultures, but caused little or no change in phosphate uptake. Quiescent 3T3 cultures switched to medium containing fresh serum and reduced levels of phosphate showed a decrease in both phosphate uptake and intracellular phosphate pool size. Cell proliferation in these cultures, however, was stimulated to the same degree as cultures switched to medium containing fresh serum and the normal amount of phosphate. In addition, quiescent secondary chick embryo cultures switched to medium containing fresh serum and no phosphate showed a decrease in the intracellular phosphate pool size. Thymidine incorporation and final cell number in these cultures, however, was stimulated to the same or higher degree than in cultures switched to medium containing fresh serum and the normal amount of phosphate. These results demonstrate that the rapid increase in phosphate uptake following addition of fresh serum to quiescent fibroblasts is not a necessary event for the initiation of proliferation.
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PMID:Serum-stimulated phosphate uptake and initiation of fibroblast proliferation. 55 45

Bovine and porcine pancreatic residue, remaining after the extraction of insulin, has been used to prepare a proteinase powder. This powder was used as a source of trypsin and chymotrypsin. The individual enzymes were isolated and purified by chromatography on sulfopropyl (SP) - Sephadex C-25 and affinity chromatography on soybean trypsin inhibitor (STI) - Sepharose. The bovine proteinase powder contained alpha-chymotrypsin, trypsin and chymotrypsin B in the ratio 5 : 2 : 1. The porcine powder contained cationic trypsin, anionic trypsin and cationic chymotrypsin in the ratio 5 : 1.4 : 3. The isolated enzymes were characterized and found to be identical with enzymes isolated from fresh tissue with the exception of porcine chymotrypsin. Porcine cationic chymotrypsin was isolated as two distinct forms, A-1 and A-2, which appear to be different activation products of porcine chymotrypsinogen A. Both forms resemble bovine alpha-chymotrypsin, a three chain structure, rather than porcine chymotrypsin Api, a two chain structure. Futhermore, the B-chain appears to be cleaved, possibly at residues Phe89-Lys90.
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PMID:The preparation of trypsins and chymotrypsins from bovine and porcine residues after insulin extraction. 56 86

Concanavalin A (Con A) inhibits fusion of trypsin-treated myoblasts. This inhibition is reversed by the addition of supraphysiological concentrations (4 micrograms/ml) of insulin either during continuous presence in culture or by pulse additions at 36 and 48 h of culture, just before the time that cultures not treated with Con A undergo myoblast fusion. This reversal is not due to the mitogenic effects of insulin. Under reversal conditions, no specific displacement of bound [125I]iodo-Con A was detected nor did insulin stimulate metabolite uptake. Cell surface replicas of hemocyanin-tagged Con A showed that insulin reversal of the inhibition of myotube formation correlated with the alteration of Con A-binding sites from a clustered configuration present in the inhibited cells to a dispersed state correlated with normal myotube formation. Although a causal relationship has yet to be shown, the data suggest that insulin-mediated reversal of Con A inhibition of myoblast fusion may be related to the ability of insulin at supraphysiological levels to alter the translational mobility of cell surface components containing glucose and/or mannose residues capable of binding Con A. Evidence is presented which suggests that insulin and Con A share common binding sites, since in the physiological range of insulin concentrations (1 ng/ml), Con A pretreatments results in an inhibition of specific [125I]iodo-insulin binding, and antagonistic interactions of insulin and Con A on metabolite uptake and cell proliferation occur. Thus, it appears that the insulin receptors of developing skeletal muscle are glycoproteins containing glycopyranosides.
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PMID:Reversal by insulin of concanavalin A inhibition of myotube formation and evidence for common binding sites. 57 92

Insulin hexamethyl ester was digested by trypsin. The resulting desoctapeptide-(B23 - 30)-insulin pentamethyl ester was purified. This compound was digested by carboxypeptidase B to remove the arginine residue B22 at the end of the B chain. Then the N-terminal amino groups of the remaining desnonapeptide-(B22 - 30)-insulin pentamethyl ester were protected with the Boc residue. The free carboxyl group of the glutamic acid residue B21 of this product was coupled to the following synthetic tetrapeptide esters: Arg-Gly-Phe-Phe-OMe, Lys(Boc)-Gly-Phe-Phe-OMe, Orn(Boc)-Gly-Phe-Phe-OMe, Cit-Gly-Phe-Phe-OMe, Ala-Gly-Phe-Phe-OMe and Gly-Gly-Phe-Phe-OMe. The syntheses of these peptide esters are described. After removal of all protecting groups, despentapeptide-insulin (B22-Arg) and analogues of this product with variation in position B22 could be obtained. They were purified by column chromatography. The biological activities of these components were determined by the mouse fall test. In the case of despentapeptide insulin (C-terminus Arg-Gly-Phe-Phe), the activity rose to the expected value of 34%. The insulin variants with amino acid residues other than arginine in position B22 had much lower activities: with lysine 13%, with ornithine 12%, with citrulline 9%, with alanine 8% and with glycine 6%. Desnonapeptide-insulin by itself posses an activity of 3%. These results demonstrate once more the essential nature of arginine residue B22 for insulin activity.
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PMID:Structure and activity of insulin, XV[1-5]. Further evidence for the importance of arginine residue B22 in the activity of insulin. Semisyntheses of despentapeptide-(B23 - 30)-insulins varied in B22 using desnonapeptide-(B22 - 30)-insulin and tetrapeptides. 59 Sep 40

Intraduodenal amino acids are known to stimulate the release of gastric inhibitory polypeptide and cholecystokinin. In order to separate and quantitate gastric inhibitory polypeptide secretion selectively, 12 normal subjects received an intraduodenal perfusion of a mixed amino acid solution (158 mM) containing either methionine, phenylalanine, tryptophan, and valine (perfusate 1), or an amino acid solution containing arginine, histidine, isoleucine, leucine, lysine, and threonine (perfusate 2). Serum concentrations of gastric inhibitory polypeptide and insulin were significantly greater in the group receiving perfusate 2 (P less than 0.001). In contrast, after administration of amino acid perfusate 1, there was only a slight increase in serum gastric inhibitory polypeptide concentration and insulin secretion increased only slightly. Mean trypsin and bilirubin outputs in the group receiving perfusate 1 were nearly 3 times greater than the outputs of the group receiving the other amino acid mixture. This study expands the importance of intraduodenal amino acid mixtures in stimulating secretion of gastric inhibitory polypeptide and insulin and quantitatively separates gastric inhibitory polypeptide release from release of hormones that stimulate pancreatic enzyme secretion, such as cholecystokinin.
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PMID:Selective release of gastric inhibitory polypeptide by intraduodenal amino acid perfusion in man. 64 19

Pancreatitis was induced in 11 miniature pigs by infusing a bile salt-trypsin solution into the pancreatic duct. Seven animals served as sham-operated controls. Serum ionized calcium, total calcium, albumin, total protein, inorganic phosphorus, urea nitrogen, magnesium, insulin, glucagon, and hematocrit were determined every six to 12 h over a period of one week in both test and control animals. We observed significant decreases in ionized and total calcium, modest decreases in albumin, and significant increases in the inorganic phosphorus, urea nitrogen, and hematocrit in the pancreatitic pigs. The latter two findings were consistent with early acute hypovolemia. Glucagon and insulin appeared to play no role in the hypocalcemia. Glucagon concentrations increased to the same degree in both test and control animals, probably as a result of the stress of being handled and operated on. The highest concentrations of inorganic phosphorus and the lowest concentrations of both ionized and total calcium were seen 18 h after the induction of pancreatitis in the test animals. These findings suggest that parathyrin (parathormone) was not being secreted in adequate amounts, or that the target organs were unresponsive to parathyrin.
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PMID:Biochemical changes in a porcine model of acute pancreatitis. 65 76

Repeated injections of cholecystokinin (CCK) during a period of up to 3 weeks significantly increased the weight of the pancreas in rats. This was associated with an increase in the amount of protein per unit weight of DNA, suggesting hypertrophy of the acinar cells, and with increase in the total amount of pancreatic DNA, indicating additional hyperplasia of the gland. CCK administration also increased the pancreatic content of amylase and trypsin, but the content of lipase remained unchanged. The rate of secretion of the two enzymes increased in the CCK-treated rats, although it appeared that the functional capacity of the individual pancreatic acinar cells was not increased. CCK injections had no effect on the insulin content of the pancreas or on the composition of the partoid glands. Repeated injections of secretin in the doses used in this study had no effect on the pancreas.
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PMID:Influence of repeated administration of cholecystokinin and secretin on the pancreas of the rat. 69 11


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