Insulinoma associated with a case of multiple endocrine neoplasia type I: Functional somatostatin receptors and abnormal glucose-induced insulin secretion.
Horm Res
; 48(2): 76-82, 1997.
Article
en En
| MEDLINE
| ID: mdl-9251924
ABSTRACT
A sporadic case of multiple endocrine neoplasia type I with coexisting insulinoma and hyperparathyroidism was investigated in vivo and in vitro. The insulinoma was localized by somatostatin receptor scintigraphy and these receptors were functionally active. Octreotide administration decreased the basal insulin and glucagon secretion by 90 and 46%, respectively. Immunocytochemistry of the insulinoma tissue was positive for insulin, chromogranin A and neuropeptide Y. The insulinoma cells were also isolated and cultured in vitro. Incubation experiments revealed that a low glucose concentration (1 mmol/l) was sufficient to increase cytosolic free calcium and to produce a maximal glucose-induced insulin release. Northern blot analysis of RNA obtained from the tumor showed a high abundance of the low Km glucose transporter GLUT1 but no transcript for the high Km glucose transporter GLUT2. The abnormal distribution of glucose transporters probably relates to the abnormal glucose sensing of insulinoma cells, and explains their sustained insulin secretion at low glucose concentrations. Whether these abnormalities share a pathogenetic link with the presence of functionally active somatostatin receptors remains to be elucidated.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias Pancreáticas
/
Neoplasias de las Paratiroides
/
Regulación Neoplásica de la Expresión Génica
/
Receptores de Somatostatina
/
Neoplasia Endocrina Múltiple Tipo 1
/
Hiperparatiroidismo
/
Insulina
/
Insulinoma
Tipo de estudio:
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Idioma:
En
Revista:
Horm Res
Año:
1997
Tipo del documento:
Article
País de afiliación:
Suiza