β → α → δ Pancreatic Islet Cellular Perfusion in Dogs

Intraislet communication between β-, α-, and δ-cells and their secretory products may theoretically occur via the paracrine (interstitial) and/or vascular routes. Recently, we have shown that there is a directed microvascular circulation in the rat islet with a cellular order of perfusion of β → α → δ. The direction of microvascular perfusion of cells within the dog islet has been controversial. Anterograde (arterial) perfusion and retrograde (reversed or venous) perfusion of a segment of isolated dog pancreas with potent insulin antibodies yielded results similar to those found in the rat pancreas (anterograde, 158 ±44% increase in glucagon and 65 ± 20% increase in somatostatin; retrograde, no change in glucagon or somatostatin). Anterograde infusion of glucagon antibody (no change in insulin, −33.5 ± 3% decrease in somatostatin) or somatostatin antibody (no change in insulin or glucagon) also yielded the same results as in the rat pancreas. Anterograde infusion of 500 pg/ml glucagon caused a larger increase in insulin secretion (245 ± 10%) than retrograde infusion (45 ± 4%), whereas somatostatin was stimulated more retrogradely (339 ± 17%) than anterogradely (121 ± 9%). Anterograde infusion of somatostatin produced a larger decrease in insulin and glucagon than did retrograde perfusion (P < .0001 for both comparisons). The retrograde infusion of 0.3 mU/ml insulin caused a decrease in glucagon but was without effect anterogradely. The results from the infusion of exogenous hormones suggest that the sensitivity of the α-, β-, and δ-cells to insulin, glucagon, and somatostatin is determined by the β → α → δ order of perfusion. The antibody studies indicate that directed microvascular perfusion is central to intraislet regulation of insular secretions in dogs.

[1]  E. Samols,et al.  Intra-islet regulation. , 1988, The American journal of medicine.

[2]  V. Marks,et al.  The order of islet microvascular cellular perfusion is B----A----D in the perfused rat pancreas. , 1988, The Journal of clinical investigation.

[3]  E. Samols,et al.  Comparison of insulin and glucagon pulsatile secretion between the rat and dog pancreas in-vitro. , 1988, Life Science.

[4]  Y. Okuda,et al.  Hormone Release From Pancreatic Islets Perfused from Venous Side , 1987, Diabetes.

[5]  K. Polonsky,et al.  Lack of direct inhibition of insulin secretion by exogenous insulin in the canine pancreas. , 1986, The Journal of clinical investigation.

[6]  E. Samols,et al.  Retrograde perfusion as a model for testing the relative effects of glucose versus insulin on the A cell. , 1986, The Journal of clinical investigation.

[7]  S. Bonner-Weir,et al.  Intra-islet insulin-glucagon-somatostatin relationships. , 1986, Clinics in endocrinology and metabolism.

[8]  L. Orci,et al.  Insulin within islets is a physiologic glucagon release inhibitor. , 1984, The Journal of clinical investigation.

[9]  K. Kataoka,et al.  A comparative study on the intercellular canalicular system and intercellular junctions in the pancreatic islets of some rodents. , 1984, Archivum histologicum Japonicum = Nihon soshikigaku kiroku.

[10]  P. Veld,et al.  Evidence Against the Presence of Tight Junctions in Normal Endocrine Pancreas , 1984, Diabetes.

[11]  D. Pipeleers.  Islet cell interactions with pancreatic B-cells. , 1984, Experientia.

[12]  D. Granger,et al.  Permeability of pancreatic capillaries to small molecules. , 1983, The American journal of physiology.

[13]  K. Polonsky,et al.  Metabolism of C-peptide in the dog. In vivo demonstration of the absence of hepatic extraction. , 1983, The Journal of clinical investigation.

[14]  G. Taborsky,et al.  Extraction of somatostatin by the pancreas. , 1983, Endocrinology.

[15]  L. Orci,et al.  Circulating somatostatin acts on the islets of Langerhans by way of a somatostatin-poor compartment. , 1982, Science.

[16]  L. Orci,et al.  New Perspectives on the Microvasculature of the Islets of Langerhans in the Rat , 1982, Diabetes.

[17]  L. Orci,et al.  Quantitative electron microscopic autoradiography of insulin, glucagon, and somatostatin binding sites on islets. , 1982, Science.

[18]  R. Unger,et al.  Inhibition of Glucagon Secretion by Exogenous Glucagon in the Isolated, Perfused Dog Pancreas , 1982, Diabetes.

[19]  L. Orci,et al.  High somatostatin uptake by the isolated perfused dog pancreas consistent with "insulo-acinar" axis. , 1982, Endocrinology.

[20]  G. Weir,et al.  Somatostatin and Pancreatic Polypeptide Secretion: Effects of Glucagon, Insulin, and Arginine , 1978, Diabetes.

[21]  J. R-Candela.  GLUCAGON AND INSULIN SECRETION , 1966 .