Pancreas

The pancreas is an exocrine gland and an endocrine gland. The exocrine tissue produces a bicarbonate solution and digestive enzymes. These substances are transported to the small intestine where they play a role in the chemical digestion of food. These functions are fully discussed in Chapter 18 on the digestive system. 

Insulin. Insulin is a peptide hormone produced by P-cells of the islets of Langerhans. It is an important anabolic hormone secreted at times when the concentration of nutrient molecules in the blood is high, such as periods following a meal. Its overall effects include allowing the body to use carbohydrates as an energy source and to store nutrient molecules. Specifically, insulin exerts its important actions on the following tissues  

Insulin also plays a role in fat metabolism. In humans, most fatty acid synthesis takes place in the liver. The mechanism of action of insulin involves directing excess nutrient molecules toward metabolic pathways leading to fat synthesis. These fatty acids are then transported to storage sites, predominantly adipose tissue. Finally, insulin stimulates the uptake of amino acids into cells where they are incorporated into proteins. 

Glucagon. Also a peptide hormone, glucagon is produced by a-cells of the islets of Langerhans. The overall effects of glucagon include  

Factors that stimulate glucagon secretion include a decrease in blood glucose an increase in blood amino acids sympathetic nervous stimulation stress and exercise. Factors that inhibit glucagon secretion include insulin and an increase in blood glucose. Table 10.2 summarizes the major functions of the hormones discussed in this chapter. 

The pancreas is a large organ containing exocrine and endocrine tissue. The islets of Langerhans make up the endocrine part and contain cells that produce insulin, glucagon and somatostatin. Cells that produce glucagon (a-cells) and somatostatin (D-cells) are found peripherally in the islets while the predominant insulin producing cells (f)-cells) are found in the centre. 

Insulin is essential for the metabolism of glucose and control of blood glucose levels, but it also has important effects on fat and protein metabolism. 

Secretion of insulin rises in response to increased blood glucose concentration. When glucose concentration falls to normal insulin secretion drops back to basal levels. A summary of the actions of insulin on glucose, protein and lipid metabolism is given in Table 6.4. 

Diabetes mellitus is a chronic metabolic disorder caused by deficiency of insulin. Hyper-glycaemia results because cells are unable to take up and use glucose. When the renal 

Medulla Phaeochromocytoma Excessive adrenaline secretion Surgical removal of adrenal gland 

Pancreatic duct obstruction by a gallstone at the ampulla of Vater. Obstruction can lead to pancreatitis, from induction of bile reflux, which eventually damages acinar cells of the pancreas. 

Laboratory diagnosis of acute pancreatitis involves the measurement of the pancreatic digestive enzymes amylase and lipase (Chapter 12). Elevated serum amylase level is a sensitive diagnostic indicator in the assessment of acute pancreatitis, but it has low specificity because there are many nonpancreatic causes of hyperamylasemia. Furthermore, amylase (M.W. 55,000) is rapidly cleared by the kidneys and returns to normal levels by the third or fourth day after onset of the abdominal pain. Amylase activity in the serum appears within 2-12 hours after the onset of 

The liver is the largest glandular organ and its parenchymal cells are called hepatocytes. Liver has numerous functions, including metabolism, detoxification, formation and excretion of bile, storage, and synthesis. Liver diseases include alcohol abuse, medication, chronic hepatitis B and C infections, steatosis and steatohepatitis, autoimmune 

The endocrine islet cells comprise only 1-2% of the pancreatic tissue. They synthesize the hormones insulin, glucagon, somatostatin, and pancreatic polypeptide. Insulin and glucagon maintain glucose homeostasis via their actions on lipid, carbohydrate, and protein metabolism. The pancreas originates from two patches of epithelium in the duodenum during the fifth week of gestation in humans. The endocrine pancreatic cells begin to differentiate very 

Acute hemorrhagic pancreatitis causes relatively minor serum alkaline phosphatase elevations, with values ranging from 4.0-13.5 Bodansky units/dl (K32) and a rough correlation between the severity of hyperbilirubinemia and the degree of hyperphosphatasemia (W16). Acute pancreatitis may be due to such disorders as alcoholism, gallstones, or hyperparathyroidism, which may themselves, by various mechanisms, give rise to serum alkaline phosphatase elevation (A4). 

Patients with this disorder frequently develop h)q)erbilirubinemia and hyperphosphatasemia during exacerbations. As each individual attack subsides, serum bilirubin concentrations return to normal at times when serum alkaline phosphatase values are still elevated. This sequence of events parallels that seen in most patients with extrahepatic biliary obstruction. 

Snape et ah (S52) reported spectacular serum alkaline phosphatase elevations in six patients with calcific pancreatitis whose serum bilirubin concentrations were only moderately elevated. Littenberg et ah (L16) studied a group of patients with recurrent pancreatitis believed to be due to alcoholism. Persistent serum alkaline phosphatase elevation (more than twice the upper reference limit for 4 weeks or more) was associated with bile duct stenosis in 15 out of 16 patients. 

Di Sant Agnese and Blanc (D13) studied two groups of patients (children) with cystic fibrosis of the pancreas. In one group, who showed no clinical evidence of liver involvement, the mean serum alkaline phosphatase was 9.3 Bodansky units/dl, which was considered normal for this age group (D13). In a second group, whose disease was complicated by biliary cirrhosis, the highest serum alkaline phosphatase value was 20 Bodansky units/dl (D13). 

Hsia et ah (H20) found that relatively few patients with cystic fibrosis of the pancreas had detectable intestinal alkaline phosphatase in their serum. They attributed this finding to the malabsorption of fat. However, the mean total values were considerably higher among the patients than among control subjects (H20). 

ACS Symposium Series American Chemical Society Washington, DC, 1980. 

Still V5X higher than for [Pt(NH3)i,] (0.25%). The spread In Pt concentrations after 7 d Is nearly 40-fold. 

One peculiarity of the phospholipid metabolism of the lung is the production of dipalmitoyl lecithin, which is an important component 

Two days after intraperitoneal injection of cholesterol-l,2- H, electron microscopic autoradiographs demonstrated that the labeled cholesterol was distributed throughout many cells in the lung and was heavily associated with the lipid vacuoles of the septal cells in the alveolar walls. Alveolar macrophages were highly labeled at 4 and 8 days after injection (Darrah, 1970). 

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Zinc is important biologically there are many zinc-protein complexes, and the human body contains about 2 g. In the human pancreas, zinc ions appear to play an essential part in the storage of insulin. 

Pancreatic lipase pancreas fats and other organic esters organic acid and alcohol (often gly ceroi) 7-0... 

Maltase pancreas, small intes tine, yeast maltose glucose 6-1 (gut) 6 6 (yeast)... 

Diastase or amylase is formed when malt is produced by the germination of barley grains. Malt is therefore a good source of the enzyme. Diastase is also secreted by the salivary glands (when it is known as ptyalin), and also by the pancreas. Its function is to hydrolysef starch to a mixture of maltose and dextrin ... 

The so-called "trypsin," obtainable from pancreatic juice and from fresh extracts of the pancreas, is not a simple enzyme but a mixture of trypsin proper (which hydrolyses proteins to proteoses and peptones) and a series of enzymes which hydrolyse these breakdown products to their constituent amino-acids. The term trypsin," when used below, refers to this mixture. 

Panax ginseng extract Pancake batters PAN copolymers Pancreas... 

Control of secretion of anterior pituitary hormones also includes inhibition by hormones produced by target organs. For example, CRH stimulates the anterior pituitary to secrete ACTH, which in turn stimulates the adrenal cortex to secrete corticosteroids. Corticosteroids then feed back to inhibit the secretion of ACTH. Feedback mechanisms are important for the control of most hormones. For example, insulin (qv) secretion from the pancreas increases in response to increased blood glucose resulting from ingestion of a meal. Insulin increases tissue uptake and metaboHsm of glucose, which lowers blood glucose and in turn reduces insulin secretion. 

The classic experiments of Von Meting and Minkowski in 1889 first impHcated the pancreas in regulating blood glucose levels removal of a dog s pancreas led directly to the development of hyperglycemia. Then in the early 1920s it was shown that an internal secretion of the pancreas could be isolated... 

The largest use of endoscopic techniques is in the examination of the gastrointestinal tract. Upper intestinal endoscopy is the examination of the esophagus, stomach, and proximal duodenum. Colonoscopy is the examination of the colon, large intestine, and in some cases the distal parts of the small intestine. Cholangiopancreatography is the examination of the biUary tree and pancreas. 

In terms of membrane area used and doUar value of the membrane produced, artificial kidneys are the single largest appHcation of membranes. Similar hoUow-fiber devices are being explored for other medical uses, including an artificial pancreas, in which islets of Langerhans supply insulin to diabetic patients, or an artificial Uver, in which adsorbent materials remove bUinibin and other toxins. 

Selenium. Selenium, thought to be widely distributed throughout body tissues, is present mostly as selenocysteine in selenoproteins or as selenomethionine (113,114). Animal experiments suggest that greater concentrations are in the kidney, Hver, and pancreas and lesser amounts are in the lungs, heart, spleen, skin, brain, and carcass (115). 

Manganese. The adult human body contains ca 10—20 mg of manganese (124,125), widely distributed throughout the body. The largest Mg " concentration is in the mitochondria of the soft tissues, especially in the Hver, pancreas, and kidneys (124,126). Manganese concentration in bone varies widely with dietary intake (126) (see Table 10). 

Two CCK receptor subtypes, CCK and CCKg are known. A related receptor, the gastrin receptor, has also been described. CCK receptors predominate in the gastrointestinal tract and pancreas and are also localized in discrete brain regions. CCKg receptors predominate in the brain. A 71623... 

Phenol. Phenol monomer is highly toxic and absorption by the skin can cause severe blistering. Large quantities can cause paralysis of the central nervous system and death. Ingestion of minor amounts may damage kidneys, Hver, and pancreas. Inhalation can cause headaches, dizziness, vomiting, and heart failure. The threshold limit value (TLV) for phenol is 5 ppm. The health and environmental risks of phenol and alkylated phenols, such as cresols and butylphenols, have been reviewed (66). 

Florfenicol concentrations in tissues and body fluids of male veal calves were studied after 11 mg/kg intramuscular doses adininistered at 12-h intervals (42). Concentrations of florfenicol in the lungs, heart, skeletal muscle, synovia, spleen, pancreas, large intestine, and small intestine were similar to the corresponding semm concentrations indicating excellent penetration of florfenicol into these tissues. Because the florfenicol concentration in these tissues decreased over time as did the corresponding semm concentrations, it was deemed that florfenicol equiUbrated rapidly between these tissues and the blood. Thus semm concentrations of florfenicol can be used as an indicator of dmg concentrations in these tissues. 

Pea.nuts, The proteins of peanuts are low in lysine, threonine, cystine plus methionine, and tryptophan when compared to the amino acid requirements for children but meet the requirements for adults (see Table 3). Peanut flour can be used to increase the nutritive value of cereals such as cornmeal but further improvement is noted by the addition of lysine (71). The trypsin inhibitor content of raw peanuts is about one-fifth that of raw soybeans, but this concentration is sufficient to cause hypertrophy (enlargement) of the pancreas in rats. The inhibitors of peanuts are largely inactivated by moist heat treatment (48). As for cottonseed, peanuts are prone to contamination by aflatoxin. FDA regulations limit aflatoxin levels of peanuts and meals to 100 ppb for breeding beef catde, breeding swine, or poultry 200 ppb for finishing swine 300 ppb for finishing beef catde 20 ppb for immature animals and dairy animals and 20 ppb for humans. 

In the treatment of diseases where the metaboUtes are not being deUvered to the system, synthetic metaboUtes or active analogues have been successfully adrninistered. Vitamin metaboUtes have been successfully used for treatment of milk fever ia catde, turkey leg weakness, plaque psoriasis, and osteoporosis and renal osteodystrophy ia humans. Many of these clinical studies are outlined ia References 6, 16, 40, 51, and 141. The vitamin D receptor complex is a member of the gene superfamily of transcriptional activators, and 1,25 dihydroxy vitamin D is thus supportive of selective cell differentiation. In addition to mineral homeostasis mediated ia the iatestiae, kidney, and bone, the metaboUte acts on the immune system, P-ceUs of the pancreas (iasulin secretion), cerebellum, and hypothalamus. 

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