Characterization of ducts isolated from the pancreas of the rat.

Abstract

Rat pancreases were minced and treated with collagenase or collagenase supplemented with chymotrypsin to yield a mixture of ducts, islets, acinar cell clusters, blood vessels, and nerves . Histologically and ultrastructurally, the isolated tissues resembled their in situ counterparts in most respects, the major difference being the destruction of the basement membranes (basal laminae) . Ducts ranging in size from the common bile/main pancreatic duct to the intercalated ducts were identified in the digest, although interlobular ducts were most frequently observed .Acinar tissue fragments were separated from nonacinar structures either by flotation through discontinuous gradients of Ficoll or by sieving, the latter technique being the more efficient . Common bile/main ducts, interlobular ducts, and blood vessels were selected manually from the nonacinar fractions . Biochemical analyses showed that the entire nonacinar fraction, as well as isolated ducts and blood vessels, contained larger alkaline phosphatase, carbonic anhydrase, and Mg-ATPase specific activities than acinar tissue, whereas acinar tissue contained larger y-glutamyltranspeptidase and amylase activities . However, >63% of the total recovered activity of each enzyme was associated with the acinar tissue . Both the association of the majority of each of these enzyme activities with the acinar tissue and the similarity in specific activities associated with ducts and blood vessels indicate that none of the enzymes tested is a unique marker for interlobular and larger ducts of the pancreas of the rat.Pancreatic ducts comprise a simple cuboidal to columnar epithelium (12,16,21) and a layer of connective tissue . The ducts serve as a conduit for the movement of exocrine enzymes from the acinar cells to the duodenum and they also produce at least part of the secretin-stimulated bicarbonaterich pancreatic fluid secretion (9, 44) . The role of the ducts in fluid/electrolyte secretion has been supported by ultrastructural (24) and micropuncture (29, 43) studies and by studies of the relatively unimpaired fluid/electrolyte secretion in rats whose acinar cells have been destroyed (14) .Carbonic anhydrase in the dog (4), (Na+K)-ATPase in the rabbit (40, 48), and HC03-ATPase in the dog and cat (45) have been implicated in pancreatic fluid secretion by experiments in which specific inhibitors (acetazolamide, ouabain, and thiocyanate, respectively) reduced fluid secretion by the intact pancreas . Histochemical studies have demonstrated the presence in the duct epithelium J. CELL BIOLOGY C The Rockefeller University Press

Immunocytochemical localization of gamma-glutamyltranspeptidase, GP-2 and amylase in the rat exocrine pancreas: the concept of zymogen granule membrane recycling after exocytosis.

“…This localization of GGT in the rat pancreas acinar cell is concordant with some previous localizations using biochemical and histochemical methods (10, 16,17,34). Indeed, biochemical assays have shown that the enzyme specific activity is much higher in acinar than in ductal tissue (16).…”

“…Indeed, biochemical assays have shown that the enzyme specific activity is much higher in acinar than in ductal tissue (16). However, there are some reports stating that the enzyme is associated with intercalated and intralobular ducts in both rat and human pancreases (37,38).…”

Isolation of Ducts From the Pancreas of Copper‐deficient Rats

“…Using this technique it was possible to obtain millimetre lengths of quite small interlobular ducts. Unfortunately, the epithelial cells exhibited gross blebbing of the apical and basal plasma membranes, and loss of their basement membrane (Githens et al 1980). An alternative approach is to begin with glands taken from copper-deficient rats.…”

“…However, in only one of these studies (Wizemann et al 1974) were ducts smaller than either the main pancreatic or common bile/pancreatic duct obtained. Ductal elements have also been harvested from collagenase digests of the rat gland (Githens, Holmquist, Whelan & Ruby, 1980;Sarras & Githens, 1982). Using this technique it was possible to obtain millimetre lengths of quite small interlobular ducts.…”

Histochemistry of Pancreas in Large White Yorkshire and Desi Pigs

“…Similar observations were also noted by Divya et al, (2015) in Madras red sheep and McMinn and Kugler (1961) in mouse and rat. The stroma and islets of Langerhans showed weak alkaline phosphatase reaction as stated by Githens et al, (1980) in rat.…”