2,3,7,8-Tetrachlorodibenzo-p-dioxin-induced impairment of glucose-stimulated insulin secretion in isolated rat pancreatic islets.
We have explored the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) administration on the secretory function of isolated rat pancreatic islets. Twenty-four hours after TCDD administration (1 microg/kg b.w., i.p.), rats showed no significant differences in plasma glucose, insulin, triglycerides and leptin levels whereas plasma-free fatty acids were significantly increased with respect to untreated controls. In isolated islets, DNA and protein content were unchanged, whereas insulin content was significantly decreased in TCDD-treated rats. Incubation with different concentrations of glucose demonstrated a significant impairment of glucose-stimulated insulin secretion in islets isolated from TCDD-treated rats, whereas insulin release was better preserved upon alpha-ketoisocaproate stimulation. A significant reduction of [3H]-2-deoxy-glucose uptake was observed in pancreatic tissue of TCDD-treated rats, whereas no significant reduction in GLUT-2 protein levels was detectable by immunoblotting in islets from TCDD-treated rats. We concluded that low-dose TCDD could rapidly induce significant alterations of the pancreatic endocrine function in the rat.
Novelli
Michela
M
Dipartimento di Patologia Sperimentale, Biotecnologie Mediche, Infettivologia ed Epidemiologia, Università degli Studi di Pisa, Via Roma, 55 Scuola Medica, 56126 Pisa, Italy.
Piaggi
Simona
S
De Tata
Vincenzo
V
D000818:Animals; D001786:Blood Glucose; D004247:DNA / Q000378:metabolism; D004785:Environmental Pollutants / Q000633:toxicity*; D005947:Glucose / Q000378:metabolism*; D015151:Immunoblotting; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001786:Blood Glucose; D004785:Environmental Pollutants; D007328:Insulin; D000072317:Polychlorinated Dibenzodioxins; D004247:DNA; D005947:Glucose