Detection of P-glycoprotein on endothelial and endocrine cells of the human pancreatic islets by C 494 monoclonal antibody

Summary P-glycoprotein, an integral membrane protein acting as an energy-dependent efflux pump, has been detected immunocytochemically in the human pancreatic islets using C 494 monoclonal antibody. Intense P-glycoprotein immunoreactivity was found in both endothelial cells of islet blood capillaries and in endocrine cells. Strong expression of P-glycoprotein has been found in the capillary blood vessels at blood-tissue barrier sites and in numerous kinds of cells with secretory/excretory function. Therefore the present findings suggest that P-glycoprotein may play a role in controlling the composition of the extracellular fluids and the intracellular milieu of endocrine islet cells and possibly in regulating their secretory activity.     

Protective effect of CR 1409 (cholecystokinin antagonist) on experimental pancreatitis in rats and mice

CR 1409, a glutaramic acid derivative with competitive cholecystokinin-antagonistic activity, was administered IP and evaluated in comparison with proglumide (the model CCK-receptor antagonist), gabexate (protease inhibitor) and PGE₂ (cytoprotective) on two different models of experimental pancreatitis. Acute pancreatitis was induced in mice by six IP injections of 50 μg/kg caerulein at hourly intervals. The drugs were administered 30 minutes before each caerulein administration. Blood samples and pancreata were collected 3 hours after the last caerulein injection. In the second experiment, pancreatitis was induced in rats by injecting 0.3 ml 6% sodium taurocholate interstitially into the pancreas. The drugs were administered twice, 30 minutes before and 3 hours after taurocholate. The animals were killed 6 hours after laparotomy and blood samples and pancreata were collected. CR 1409 exhibited on both pancreatitis models a protective effect in a dose range of 0.3–10 mg/kg. Proglumide exhibited a protective activity at higher doses (200–400 mg/kg). Gabexate and PGE₂ were effective only in pancreatitis induced by taurocholate in a dose range of 30–60 mg/kg and 60–130 μg/kg respectively. These results, showing a high protective effect of CR 1409 on different models of acute pancreatitis, suggest an important role of CCK in the pathogenesis of pancreatitis.     

Intermediate cell tumour of the pancreas in rat

A malignant tumour of the rat pancreas with features of both acinar and endocrine cells is presented. This consisted of a continuous cytoplasmic mass with numerous dispersed nuclei and branches protruding from its borders invading the surrounding exocrine tissue. The most prominent characteristic of the tumour was the co-existence of zymogen and endocrine secretory granules and cytoplasmic organelles typical of both acinar and islet cells. Some hypotheses are put forward concerning the origin of the tumour and its vasculature.     

Isopongaglabol and 6-methoxyisopongaglabol,two new hydroxyfuranoflavones from Pongamia glabra

Isopongaglabol and 6-methoxyisopongaglabol, two new hydroxyfuranoflavones, together with two furanoflavones 5-methoxyfurano(8,7-4″,5″)flavone and 5-methoxy-3′,4′-methylenedioxyfurano(8,7-4″,5″)flavone, two simple flavones, desmethoxykanugin and fisetin tetramethyl ether, a chromenoflavanone, ovalichromene B, two triterpenes, cycloart-23-ene-3β,25-diol and friedelin, and β-sitosterol-β-d-glucoside were isolated from the petrol and CHCl₃ extracts of the flowers of Pongamia glabra. The structures of isopongaglabol and 6-methoxyisopongaglabol have been established as 4′-hydroxyfurano(8,7-4″,5″)flavone and 4′-hydroxy-6-methoxyfurano(8,7-4″,5″)flavone, respectively, on the basis of the spectral evidence and they have been confirmed by synthesis.