Differential expression of rat pancreatic islet beta-cell glucose transporter (GLUT 2), proinsulin and islet amyloid polypeptide genes after prolonged fasting, insulin-induced hypoglycaemia and dexamethasone treatment

The question posed by these studies was whether chronic adaptive changes in glucose-stimulated insulin secretion are accompanied by comparable changes in islet Beta-cell glucose transporter (GLUT 2) gene expression. Control, fasted (3-day), insulin-injected hypoglycaemic (5-day), and dexamethasone-treated (4-day) rats (n = 5 for each condition), were studied. After fasting significant decrements in proinsulin mRNA/microgram RNA (-32%, p < 0.05) and islet amyloid polypeptide mRNA/microgram RNA (-44%, p < 0.05) were observed, while there was no change in GLUT 2 mRNA/microgram RNA (-13%, p > 0.05). After insulin-induced hypoglycaemia, decrements in proinsulin mRNA/microgram RNA (-49%, p < 0.01) and islet amyloid polypeptide mRNA/microgram RNA (-44%, p < 0.01) were also observed, with no change in islet GLUT 2 mRNA/microgram RNA (-18%, p > 0.05). Dexamethasone treatment resulted in a marked stimulatory effect on proinsulin mRNA/microgram RNA (+236%, p < 0.001) and islet amyloid polypeptide mRNA/microgram RNA (+221%, p < 0.01), while again there was no change in islet GLUT 2 mRNA/microgram RNA (+0.3%, p > 0.05). Quantitative immunoblot analysis with a GLUT 2 specific antibody revealed no change in islet GLUT 2 protein with fasting, but a small decrease (-39 +/- 11%) in islet GLUT 2/microgram protein after insulin-induced hypoglycaemia. These results do not support the hypothesis that chronic changes in glucose-stimulated insulin secretion are accompanied by changes in GLUT 2 expression. In contrast to the lack of correlation with GLUT 2, there was a striking correlation between proinsulin and islet amyloid polypeptide mRNAs for all experimental conditions (r = 0.974, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS).

Medienart:

Artikel

Erscheinungsjahr:

1992

Erschienen:

1992

Enthalten in:

Zur Gesamtaufnahme - volume:35

Enthalten in:

Diabetologia - 35(1992), 12 vom: 01. Dez., Seite 1125-32

Sprache:

Englisch

Beteiligte Personen:

Koranyi, L [VerfasserIn]
Bourey, R [VerfasserIn]
Turk, J [VerfasserIn]
Mueckler, M [VerfasserIn]
Permutt, M A [VerfasserIn]

Themen:

24937-83-5
63231-63-0
7S5I7G3JQL
9035-68-1
Amyloid
Blood Glucose
Dexamethasone
Insulin
Islet Amyloid Polypeptide
Journal Article
Monosaccharide Transport Proteins
Poly A
Proinsulin
RNA
RNA, Messenger
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Anmerkungen:

Date Completed 05.02.1993

Date Revised 16.08.2019

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM012628727