Microcirculation of the Rat Pancreas, with Special Reference to the Insulo-Acinar Portal and Insulo-Venous Drainage Systems: A Further Scanning Electron Microscope Study of Corrosion Casts.

Murakami, Takuro; Fujita, Tsuneo

doi:10.1679/aohc.55.453

Cited by 35 publications

(30 citation statements)

References 24 publications

(34 reference statements)

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“…Streptozotocin treatment resulted in an even uptake of 3H-leucine by pen-and tele-insular acinar cells with equal density of silver grains in their associated intercalated ducts. Based on these results, we have agreed with the previous authors (13,15) that the cells of peninsular acini are more active in protein synthesis than the cells of tele-insular acini, due to exposure of the former cells to high concentrations of insulin, which are caused by the blood flow directly from the islet capillaries toward pen-insular acini (4,(16)(17)(18)(19).…”

Section: Discussionsupporting

confidence: 90%

Quantitative Radioautographic Study on 3H-Leucine Uptake of Peri- and Tele-Insular Acinar Cells of the Pancreas in Normal and Streptozotocin-Diabetic Mice.

Aughsteen

Kataoka

1994

Acta Histochem. Cytochem

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The uptake of 3H-leucine by peri-and tele-insular acinar cells of the pancreas was analyzed quantitatively 60 min after the intraperitoneal injection of 3H-leucine in normal and streptozotocin-diabetic mice. A large tissue sample was analyzed and the grain density was counted with a color image analyzer equipped with a computer. The radioactivity was expressed as number of silver grains per acinar cell as well as per unit area of acinar tissue. In normal mice, the radioactivity in peri-insular acinar cells was 43% greater than in tele-insular acinar cells. The intercalated ducts associated with the former also showed a larger number of silver grains. In streptozotocin-diabetic mice, the uptake of 3H-leucine in peri-and teleinsular acinar cells was almost similar. The estimate of mean acinar cell profile area was 30% larger in the peri-insular acini of normal mice, while no difference was observed between the estimates of peri-and teleinsular acinar cells of diabetic mice.These results confirm previous reports that the B cell serection plays a certain role in the protein synthesis of pancreatic acinar cells, especially for the cells of peri-insular acini.

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Section: Discussionsupporting

confidence: 90%

Quantitative Radioautographic Study on 3H-Leucine Uptake of Peri- and Tele-Insular Acinar Cells of the Pancreas in Normal and Streptozotocin-Diabetic Mice.

Aughsteen

Kataoka

1994

Acta Histochem. Cytochem

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“…In this way, both in vitro and in vivo results are consistent with ␦-cell SST exerting an inhibitory paracrine influence on islet ␣-and ␤-cells. The route through which ␦-cell SST reaches ␣-and ␤-cells is uncertain; early reports on islet blood flow do not support a vascular route from ␦-cells to ␣-and ␤-cells (35,36), although other data do imply a direct vascular route from ␦-to ␤-cells (37). Alternatively, SST delivery may be mediated by diffusion via interstitial compartments (38,39) independent of islet vasculature.…”

Section: Diabetes Vol 58 February 2009mentioning

confidence: 99%

Somatostatin Secreted by Islet δ-Cells Fulfills Multiple Roles as a Paracrine Regulator of Islet Function

Hauge-Evans

King

Carmignac³

et al. 2009

Diabetes

280

263

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OBJECTIVE-Somatostatin (SST) is secreted by islet ␦-cells and by extraislet neuroendocrine cells. SST receptors have been identified on ␣-and ␤-cells, and exogenous SST inhibits insulin and glucagon secretion, consistent with a role for SST in regulating ␣-and ␤-cell function. However, the specific intraislet function of ␦-cell SST remains uncertain. We have used Sst Ϫ/Ϫ mice to investigate the role of ␦-cell SST in the regulation of insulin and glucagon secretion in vitro and in vivo. RESEARCH DESIGN AND METHODS-Islet morphology wasassessed by histological analysis. Hormone levels were measured by radioimmunoassay in control and Sst Ϫ/Ϫ mice in vivo and from isolated islets in vitro. RESULTS-Islet size and organization did not differ between SstϪ/Ϫ and control islets, nor did islet glucagon or insulin content. Sst Ϫ/Ϫ mice showed enhanced insulin and glucagon secretory responses in vivo. In vitro stimulus-induced insulin and glucagon secretion was enhanced from perifused Sst Ϫ/Ϫ islets compared with control islets and was inhibited by exogenous SST in Sst Ϫ/Ϫ but not control islets. No difference in the switch-off rate of glucose-stimulated insulin secretion was observed between genotypes, but the cholinergic agonist carbamylcholine enhanced glucose-induced insulin secretion to a lesser extent in Sst Ϫ/Ϫ islets compared with controls. Glucose suppressed glucagon secretion from control but not Sst Ϫ/Ϫ islets.CONCLUSIONS-We suggest that ␦-cell SST exerts a tonic inhibitory influence on insulin and glucagon secretion, which may facilitate the islet response to cholinergic activation. In addition, ␦-cell SST is implicated in the nutrient-induced suppression of glucagon secretion. Diabetes 58:403-411, 2009

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“…Thus, islet hormones conveyed to the acinar epithelium via an islet-acinar portal circulation appear to modulate exocrine pancreatic secretion (see Williams & Goldfine, 1985;Murakami & Fujita, 1992). In pancreatic acinar cells, agonist-induced Ca2+ influx is required for regulation of cytosolic Ca2+, refilling of internal Ca2+ stores and secretion (Muallem, 1989).…”

Section: Introductionmentioning

confidence: 99%

Insulin stimulates cationic amino acid transport activity in the isolated perfused rat pancreas

Muñoz

Sweiry²,

Ge³

1995

Experimental Physiology

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SUMMARYThe effects of exogenous insulin, glucagon and streptozotocin-diabetes on influx (15 s) of L-lysine via a cationic amino acid transporter resembling system y+ were investigated in the isolated perfused rat pancreas. In non-diabetic pancreata, transport of L-lysine was saturable with an apparent Km of 2-11 + 0.29 mm and Vma_ of 2 21 + 0 20,mol min-' g-1 (n = 6). Bovine insulin (100 # u ml ') increased the maximal transport rate (Vmax = 349 + 030 /tmol min-' g-', n = 4, P < 0.05) for L-lysine 1 6-fold without altering the Km. L-Lysine transport was not elevated significantly in diabetic pancreata, although insulin (1O00 /tu ml-') enhanced transport to values measured in non-diabetic preparations. Human glucagon (1.5 x 10-9 M) had no stimulatory effect on L-lysine transport. These findings provide the first evidence that exogenous insulin stimulates cationic amino acid transport activity in the exocrine pancreatic epithelium. Activation of the cationic pancreatic amino acid transporter may provide a mechanism to enhance the supply of L-arginine and thus sustain nitric oxide-mediated pancreatic secretion in response to islet hormones and secretagogues.

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Microcirculation of the Rat Pancreas, with Special Reference to the Insulo-Acinar Portal and Insulo-Venous Drainage Systems: A Further Scanning Electron Microscope Study of Corrosion Casts.

Cited by 35 publications

References 24 publications

Quantitative Radioautographic Study on 3H-Leucine Uptake of Peri- and Tele-Insular Acinar Cells of the Pancreas in Normal and Streptozotocin-Diabetic Mice.

Quantitative Radioautographic Study on 3H-Leucine Uptake of Peri- and Tele-Insular Acinar Cells of the Pancreas in Normal and Streptozotocin-Diabetic Mice.

Somatostatin Secreted by Islet δ-Cells Fulfills Multiple Roles as a Paracrine Regulator of Islet Function

Insulin stimulates cationic amino acid transport activity in the isolated perfused rat pancreas

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