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On the possible role of thiol groups in the insulin-releasing action of mercurials, organic disulfides, alkylating agents, and sulfonylureas

Hellman, B. ; Lernmark LU ; Sehlin, J. ; Söderberg, M. and Täljedal, I. B. (1976) In Endocrinology 99(5). p.1398-1406
Abstract

The thiol activity of pancreatic islets was spectrophotometrically assayed as the formation of 6-mercaptonicotinic acid from the organic disulfide, 6, 6’-dithiodinicotinic acid. Islets containing more than 90% β-cells were microdissected from non-inbred oblob-mice. Comparisons of intact with homogenized islets indicated that the organic disulfide penetrates relatively slowly into the β-cells. When tested at concentrations known to enhance insulin release, P-chloromercuribenzene-sulfonic acid almost completely blocked the thiol activity of intact islets, whereas no significant effect was observed with iodoacetamide, D-glucose, or glibenclamide. Although glibenclamide had no demonstrable effect on the thiol activity of free L-cysteine,... (More)

The thiol activity of pancreatic islets was spectrophotometrically assayed as the formation of 6-mercaptonicotinic acid from the organic disulfide, 6, 6’-dithiodinicotinic acid. Islets containing more than 90% β-cells were microdissected from non-inbred oblob-mice. Comparisons of intact with homogenized islets indicated that the organic disulfide penetrates relatively slowly into the β-cells. When tested at concentrations known to enhance insulin release, P-chloromercuribenzene-sulfonic acid almost completely blocked the thiol activity of intact islets, whereas no significant effect was observed with iodoacetamide, D-glucose, or glibenclamide. Although glibenclamide had no demonstrable effect on the thiol activity of free L-cysteine, the binding of glibenclamide to serum albumin was decreased by blocking the albumin thiols with azobenzene-2-sulfenyl bromide. The uptake of glibenclamide by pancreatic islets was inhibited by cysteine or reduced glutathione. Cysteine, as well as 6, 6’-dithiodinicotinic acid, also seemed to interact negatively with glibenclamide as insulin secretagogue. The results support the hypothesis that organic mercurials and disulfides stimulate insulin release by blocking thiol groups in the β-cell plasma membranes. The thiol groups involved in iodoacetaniideinduced secretion may escape detection by the assay employed, or target groups other than thiols may be involved. The data on glibenclamide are compatible with, but do not unequivocally support, the notion that thiol groups may play a role in sulfonylurea-induced insulin release.

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publishing date
type
Contribution to journal
publication status
published
subject
in
Endocrinology
volume
99
issue
5
pages
9 pages
publisher
Oxford University Press
external identifiers
  • pmid:186256
  • scopus:0017054647
ISSN
0013-7227
DOI
10.1210/endo-99-5-1398
language
English
LU publication?
no
id
aac54a7d-819b-4c85-9a72-3adba302eab4
date added to LUP
2019-12-12 23:35:05
date last changed
2021-01-03 06:44:30
@article{aac54a7d-819b-4c85-9a72-3adba302eab4,
  abstract     = {<p>The thiol activity of pancreatic islets was spectrophotometrically assayed as the formation of 6-mercaptonicotinic acid from the organic disulfide, 6, 6’-dithiodinicotinic acid. Islets containing more than 90% β-cells were microdissected from non-inbred oblob-mice. Comparisons of intact with homogenized islets indicated that the organic disulfide penetrates relatively slowly into the β-cells. When tested at concentrations known to enhance insulin release, P-chloromercuribenzene-sulfonic acid almost completely blocked the thiol activity of intact islets, whereas no significant effect was observed with iodoacetamide, D-glucose, or glibenclamide. Although glibenclamide had no demonstrable effect on the thiol activity of free L-cysteine, the binding of glibenclamide to serum albumin was decreased by blocking the albumin thiols with azobenzene-2-sulfenyl bromide. The uptake of glibenclamide by pancreatic islets was inhibited by cysteine or reduced glutathione. Cysteine, as well as 6, 6’-dithiodinicotinic acid, also seemed to interact negatively with glibenclamide as insulin secretagogue. The results support the hypothesis that organic mercurials and disulfides stimulate insulin release by blocking thiol groups in the β-cell plasma membranes. The thiol groups involved in iodoacetaniideinduced secretion may escape detection by the assay employed, or target groups other than thiols may be involved. The data on glibenclamide are compatible with, but do not unequivocally support, the notion that thiol groups may play a role in sulfonylurea-induced insulin release.</p>},
  author       = {Hellman, B. and Lernmark and Sehlin, J. and Söderberg, M. and Täljedal, I. B.},
  issn         = {0013-7227},
  language     = {eng},
  month        = {01},
  number       = {5},
  pages        = {1398--1406},
  publisher    = {Oxford University Press},
  series       = {Endocrinology},
  title        = {On the possible role of thiol groups in the insulin-releasing action of mercurials, organic disulfides, alkylating agents, and sulfonylureas},
  url          = {http://dx.doi.org/10.1210/endo-99-5-1398},
  doi          = {10.1210/endo-99-5-1398},
  volume       = {99},
  year         = {1976},
}