pituitrin and Pancreatic-Diseases

Ultrasonic examination of the pancreas is rendered difficult by the echogenic characteristics of the organ, by its depth, by the overlying gas, and by bony structures and anatomic variations. The reintroduction of gray-scale imaging promises to simplify the technique and expand its usefulness. The 75Se-/-selenomethionine scan is a reliable test when performed after effective pancreatic stimulation with a scintillation camera that permits the angulation required to separate pancreas from liver. Gallium-67-citrate may be important for both mapping inflammatory processes and imaging some tumors. Retrograde pancreatography has developed into a rather reliable and sensitive method of visualizing pancreatic duct abnormalities. Angiography remains the most reliable technique for finding small lesions, while computerized axial tomography appears a promising modality in the near future. In acute pancreatitis, gallium scanning may find a place alongside plain films, GI series, and echography. Chronic pancreatitis appears best studied by pancreatography, possibly with selenomethionine scanning as a function study and echography to find associated mass lesions. Pseudocysts are most easily located by ultrasound examination. Screening for pancreatic carcinoma is done most effectively with selenomethionine scanning when the index of suspicion is low and with pancreatography or arteriography when it is high. Echography is useful for localization for aspiration biopsy and for sequential evaluation of therapeutic response. Islet-cell tumors are best found by angiographic studies.

Topics: Acute Disease; Adenoma, Islet Cell; Adult; Female; Gallium Radioisotopes; Hormones, Ectopic; Humans; Male; Middle Aged; Pancreatic Cyst; Pancreatic Diseases; Pancreatic Neoplasms; Pancreatitis; Paraneoplastic Endocrine Syndromes; Radionuclide Imaging; Selenomethionine; Ultrasonography; Vasopressins; Zollinger-Ellison Syndrome

Vasoactive intestinal peptide (VIP), originally isolated from hog small intestinal mucosa, has been shown to cause small intestinal secretion. More recently, this peptide has been identified in the plasma and tumors of patients with the so-called "pancreatic cholera" syndrome. In order to explore the possible role of VIP in the pathogenesis of this syndrome, we examined the effects of this peptide and other hormones on the cyclic AMP levels, adenylate cyclase activity, and ion transport in in vitro preparations of ileal mucosa. In rabbit ileal mucosa, VIP (20 mug/ml) caused a prompt fivefold increase in cyclic AMP level, whereas nine other hormones, which have been postulated to cause intestinal secretion, failed to exert such an effect. Pentagastrin and glucagon also failed to increase cyclic AMP levels in canine ileal mucosa. An increase in mucosal cyclic AMP levels was observed at a VIP concentration of 0.1 mug/ml and appeared to be nearly maximal at 2.0 mug/ml. VIP (100 mug/ml) stimulated adenylate cyclase activity in a membrane preparation from rabbit ileal mucosa. Secretin (6.0 x 10(-5) M) failed to do so. When added to the serosal side of isolated rabbit ileal mucosa clamped in an Ussing chamber, VIP (2 mug/ml) increased short-circuit current (SCC) and caused net secretion of both Cl and Na. Net Cl secretion exceeded net Na secretion. These effects of VIP on mucosal cyclic AMP metabolism and ion transport are similar to those observed with cholera enterotoxin and certain prostaglandins. VIP was also tested with normal human ileal mucosa. At a concentration of 2 mug/ml it caused a fivefold increase in cyclic AMP level and an increase in SCC of the same magnitude as that caused by 5 mM theophylline. Addition of a second 2-mug/ml dose of VIP and addition of theophylline after VIP produced no further change in SCC. We conclude the VIP stimulates adenylate cyclase and active ion secretion in both rabbit and human ileal mucosa. This may be related to the pathogenesis of diarrhea in patients with the pancreatic cholera syndrome.

Topics: Adenylyl Cyclases; Animals; Bradykinin; Calcitonin; Carbachol; Cyclic AMP; Diarrhea; Dogs; Glucagon; Ileum; Intestinal Mucosa; Intestinal Secretions; Male; Pancreatic Diseases; Pentagastrin; Peptides; Rabbits; Serotonin; Theophylline; Vasomotor System; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Bethanechol Compounds; Cholecystokinin; Female; Glucagon; Humans; Pancreatic Cyst; Pancreatic Diseases; Pancreatic Neoplasms; Pancreatitis; Propantheline; Radioisotopes; Radionuclide Imaging; Rats; Selenium; Stomach Ulcer; Vasopressins