Summaryby CF, ~ancreatic secretions have not been as extensively studiedPancreatic juice was collected from rabbits treated with reserpine and from untreated controls. The volume of pancreatic juice secreted, flow rate and the bicarbonate output were all significantly reduced in the treated animals during both spontaneous flow and during secretin-stimulated flow. On the other hand, the total protein concentration, the amylase activity and the calcium concentration of the pancreatic juice were all significantly elevated in the treated animals. The elevation in the total protein concentration appeared to be due to both increased amounts of protein and decreased amounts of water. Of particular interest was that secretin stimulation caused the same % increase in the flow rate and output of pancreatic juice in both control and reserpine treated rabbits. he method-by which fluid is secreted by-the treated animal, therefore, appeared to be depressed at all times and under all conditions. Decreased volumes of pancreatic juice, a decreased bicarbonate output and increased concentrations of protein and calcium are found in this model and are consistent with clinical findings present in the pancreatic secretions obtained from individuals with cystic fibrosis. Therefore, the similarities between secretions of the reserpine treated rabbit and those observed in the cystic fibrosis patient support its use as an experimental model for investigating the abnormal pancreatic secretions in this disease. SpeculationRabbits treated with reserpine for 7 days secrete smaller volumes of pancreatic juice at lower rates of flow during both spontaneous and secretin-stimulated conditions. This juice contains elevated levels of total protein, enzymes, calcium and smaller amounts of bicarbonate. Because these alterations are common in patients with CF, the reserpine-treated rabbit appears to be a good model to investigate the perturbations taking place in the pancreas during the course of this disease.The study of cystic fibrosis (CF) has been hampered by the lack of an equivalent disease in a lower species. For this reason attempts have been made to pharmacologically perturb the exocrine secretions of an experimental animal to the point where they resemble what is seen in this disease (8,10). One such model is the chronically reserpinized rat. Rats treated for several days with reserpine develop morphologic and secretory changes in the submaxillary gland (9, 11) and in the pancreas (6, 16) which resemble those present in CF patients. The Na+ transport inhibitory factor, present in the saliva of CF patients (7) has been demonstrated in the saliva of reserpinized rats as well (13). In addition, this treatment increases the pulmonary secretion of phospholipids (14), total protein (21) and of a specific type of glycoprotein which is also present in lung lavages of CF patients (21). These alterations seem to indicate that reserpinization creates a generalized exocrine gland dysfunction resulting in a fairly complete animal model with which this d...

cell m e m b r a n e erythrocyte cystic fibrosis osmotic water permeability SummaryThe abnormally high concentrations of electrolytes and organic solutes found in the glandular secretions of individuals with cystic fibrosis may arise from decreased water content rather than perturbed solute transport. Thus, it is possible that the abnormalities insolute concentrations are a result of a reduced water movement into the secretory product. It is our hypothesis that if an abnormality exists in the transport of water across secretory cell membranes, this defect may also be expressed in nonsecretory cell membrane permeability to water. We report here osmotic water permeability measurements on red cells and 11 cystic fibrosis patients ranging in age from 2 to 20 years and eight normal individuals. The mean hydraulic conductivity for the patients of 1.23 f 0.13 cm3/dyne sec is significantly less ( P < 0.001) than that of normal individuals who have permeabilities of 1.45 f 0.11 cm3/dyne sec. Analysis showed that the osmotic water permeability correlates well with the Shwachman score ( r = 0.76). Patients who are in the poorest clinical condition show the lowest hydraulic conductivities.