Transport and storage of 5-hydroxytryptamine in pancreatic β-cells
Hellman, Bo ; Lernmark, Åke LU
; Sehlin, Janove
and Täljedal, Inge Bert
(1972)
In Biochemical Pharmacology
21(5).
p.695-706
- Abstract
To elucidate the role of biogenic amines in insulin secretion, pancreatic islets rich in β-cells were microdissected from obese-hyperglycemic mice and were incubated with 14C-labelled 5-hydroxytryptamine (5-HT). The saturability of uptake and the fact that 5-HT was accumulated to high levels indicated that the β-cells possess a transport system with great capacity for this amine. The initial uptake was not sensitive to glucose or diazoxide. Efflux of radioactivity from islets preloaded with 14C-labelled 5-HT exhibited complex kinetics suggesting incorporation of the amine into some less mobile compartment of the β-cells. This compartment may be the insulin-containing secretory granules, since homogenization and... (More)
To elucidate the role of biogenic amines in insulin secretion, pancreatic islets rich in β-cells were microdissected from obese-hyperglycemic mice and were incubated with 14C-labelled 5-hydroxytryptamine (5-HT). The saturability of uptake and the fact that 5-HT was accumulated to high levels indicated that the β-cells possess a transport system with great capacity for this amine. The initial uptake was not sensitive to glucose or diazoxide. Efflux of radioactivity from islets preloaded with 14C-labelled 5-HT exhibited complex kinetics suggesting incorporation of the amine into some less mobile compartment of the β-cells. This compartment may be the insulin-containing secretory granules, since homogenization and centrifugation of preloaded islets revealed closely parallel sedimentation profiles for insulin and 14C. The apparent co-sedimentation of insulin and 5-HT probably reflects the ultrastructural organization of the β-cells, as insignificant radioactivities were recovered in the sediments after adding 14C-labelled 5-HT to homogenized islets. Furthermore, gel filtration of insulin on 5-HT-equilibrated Sephadex G-50 did not indicate any great affinity of insulin for the amine. Neither glucose nor glibenclamide could be shown to mobilize granule-bound 5-HT from intact β-cells. In these experiments insulin release was slow despite a glucose concentration as high as 20 mM. It seems possible that co-storage of insulin and 5-HT reduces the ability of β-granules to undergo normal emiocytosis.
(Less)
- author
- Hellman, Bo
; Lernmark, Åke
LU
; Sehlin, Janove
and Täljedal, Inge Bert
- publishing date
- 1972-03-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Biochemical Pharmacology
- volume
- 21
- issue
- 5
- pages
- 12 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:0015310788
- pmid:4623249
- ISSN
- 0006-2952
- DOI
- 10.1016/0006-2952(72)90062-7
- language
- English
- LU publication?
- no
- id
- 433114d4-7238-4899-836a-9aadcb572601
- date added to LUP
- 2019-09-18 12:24:00
- date last changed
- 2024-03-13 08:24:06
@article{433114d4-7238-4899-836a-9aadcb572601,
abstract = {{<p>To elucidate the role of biogenic amines in insulin secretion, pancreatic islets rich in β-cells were microdissected from obese-hyperglycemic mice and were incubated with <sup>14</sup>C-labelled 5-hydroxytryptamine (5-HT). The saturability of uptake and the fact that 5-HT was accumulated to high levels indicated that the β-cells possess a transport system with great capacity for this amine. The initial uptake was not sensitive to glucose or diazoxide. Efflux of radioactivity from islets preloaded with <sup>14</sup>C-labelled 5-HT exhibited complex kinetics suggesting incorporation of the amine into some less mobile compartment of the β-cells. This compartment may be the insulin-containing secretory granules, since homogenization and centrifugation of preloaded islets revealed closely parallel sedimentation profiles for insulin and <sup>14</sup>C. The apparent co-sedimentation of insulin and 5-HT probably reflects the ultrastructural organization of the β-cells, as insignificant radioactivities were recovered in the sediments after adding <sup>14</sup>C-labelled 5-HT to homogenized islets. Furthermore, gel filtration of insulin on 5-HT-equilibrated Sephadex G-50 did not indicate any great affinity of insulin for the amine. Neither glucose nor glibenclamide could be shown to mobilize granule-bound 5-HT from intact β-cells. In these experiments insulin release was slow despite a glucose concentration as high as 20 mM. It seems possible that co-storage of insulin and 5-HT reduces the ability of β-granules to undergo normal emiocytosis.</p>}},
author = {{Hellman, Bo and Lernmark, Åke and Sehlin, Janove and Täljedal, Inge Bert}},
issn = {{0006-2952}},
language = {{eng}},
month = {{03}},
number = {{5}},
pages = {{695--706}},
publisher = {{Elsevier}},
series = {{Biochemical Pharmacology}},
title = {{Transport and storage of 5-hydroxytryptamine in pancreatic β-cells}},
url = {{http://dx.doi.org/10.1016/0006-2952(72)90062-7}},
doi = {{10.1016/0006-2952(72)90062-7}},
volume = {{21}},
year = {{1972}},
}