Alterations of pancreatic growth and of GP-2 content in the reserpinized rat model of cystic fibrosis

Life with the pancreas: A personal experience

This review article has primary objective to summarize pancreatic research which has been done in our laboratory since 1965, the first year of the author's registration in the Ph.D. program at the University of Sherbrooke (Canada). It covers the following major topics of pancreatic physiology: controls of pancreatic adaptation to diet, control of pancreatic enzyme secretion, control of pancreatic enzyme synthesis, control of pancreatic growth, intracellular events stimulated during pancreatic growth, pancreas regeneration after pancreatitis and pancreatectomy, the pancreatic cholecystokinin receptor types 1 and 2, growth control and cell signaling in pancreatic cancer cells and finally, cystic fibrosis.

Proteomic analysis of domestic pig pancreas during development using two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry

Pig pancreas may be a therapeutic resource for human diabetic patients. However, this potential is hindered by a lack of knowledge of the molecular events of pig pancreas development. In this study, the embryonic day 60, neonate and 6-month protein profiles of pig pancreas were ascertained at using two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization-time of flight mass spectrometry. Twenty four proteins were differentially expressed during pig pancreas development. Among them, 12 spots increased and 7 spots decreased according to development. The expression of 5 protein were highest at birth. Expression of digestive enzymes including trypsin, pancreatic triacylglycerol lipase and pancreatic alpha-amylase was elevated in adults, whereas chymotrypsins were highly expressed in neonates. Proteins that were abundantly expressed during gestation were alpha-1-antitrypsin, alpha-fetoprotein and transferrins. Taken together, we found out that several proteins were significantly up- or down- regulated from pig pancreas based on developmental stage. This study will provide basis for understanding development of pig pancreas.

Models of exocrine pancreatic pathologies: a microscopical point of view

The objective of this review is to emphasize the contribution of optical and electronic microscopy to the study of the normal and pathological rat pancreas. These basic techniques used to explore the pancreatic morphology are capital to precisely localize specific enzymes or proteins in cellular subcompartments, to establish the normal or the pathological state of the gland, and to detect and describe unusual structures that appear under certain experimental conditions.

Plasma immunoreactive cationic trypsin(ogen) pattern in reserpinized rat model of cystic fibrosis. Resemblance to humans

Plasma immunoreactive cationic trypsin (ogen) is elevated in cystic fibrosis during early infancy, before exocrine pancreatic insufficiency is fully developed. The recently developed cystic fibrosis mouse model carrying a mutated gene presents only minor pathologic findings in the pancreas. However, the reserpinized rat model shows cystic fibrosis-like defects in various exocrine glands, including the exocrine pancreas. Plasma immunoreactive cationic trypsin (ogen) has not been studied yet in this model. The present study explored the plasma immunoreactive cationic trypsin (ogen) pattern and possible mechanisms in this rat model. Plasma immunoreactive cationic trypsin (ogen) (RIA), pancreatic juice volume, protein, and trypsin, and pancreas weight were determined in rats treated with reserpine (0.5 mg/kg/day subcutaneously) for four or seven days, following cerulein stimulation (5 micrograms/kg/dose intraperitoneally), versus pair-fed controls. The first of four consecutive 30 min periods revealed peak values in all parameters. Four-day reserpine-treated rats demonstrated significantly higher plasma immunoreactive cationic trypsin (ogen) levels (167.3 +/- 12.8 vs 88.9 +/- 6.1 ng/ml; P < 0.0001) with similar values of pancreatic juice trypsin (8.2 +/- 2.4 vs 6.6 +/- 1.8 units/mg protein; P = NS) and volume (5.6 +/- 1.3 vs 4.2 +/- 1.6 mg/min/g pancreas; P = NS), compared to controls. Rats treated with reserpine for seven days revealed significantly lower values of plasma immunoreactive cationic trypsin (ogen) (39.2 +/- 8.4 vs 66.8 +/- 4.9 ng/ml; P < 0.001), pancreatic juice trypsin (1.9 +/- 0.3 vs 3.2 +/- 0.9 units/mg protein; P < 0.001) and volume (1.6 +/- 0.7 vs 3.1 +/- 0.6 mg/min/g pancreas; P < 0.001) compared to controls. We conclude that the reserpinized rat model resembles human cystic fibrosis as to elevated plasma immunoreactive cationic trypsin (ogen) before exocrine pancreatic insufficiency is fully developed. Since exocrine pancreatic volume secretion is intact at this stage, the mechanism of elevated plasma immunoreactive cationic trypsin is probably not due to ductular obstruction. We suggest that this model be studied further in order to investigate other possible mechanisms.

A competition enzyme-linked immunosorbent assay (ELISA) for the measurement of pancreatic GP-2 glycoprotein

A competition enzyme-linked immunosorbent assay has been developed for the quantitative detection of soluble and membrane-bound GP-2, a glycoprotein which is confined to the exocrine pancreas. Zymogen granule membranes fixed to microtiter plates with poly-L-lysine were used as the source of antigen. Detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS] was added to the assay in order to reveal all the antigens, more particularly in membranous samples. Presence of detergent at concentrations as high as 0.5% did not interfere with any particular steps of the ELISA. This competition ELISA can detect 10 ng of GP-2 and will be useful for measuring soluble as well as membrane GP-2 in order to elucidate its role in the secretory process of the pancreas as well as in certain pathologies such as cystic fibrosis.