title: An experimental model of diabetes and cancer in rats.
abstract: The aim of this study was to develop an experimental model for the study of cancer associated with diabetes. For diabetes induction, Sprague-Dawley rats were given streptozotocin (STZ, 90 mg/kg body weight (BW), by intraperitoneal injection on the second day of life. For mammary tumour induction, rats were injected with 50 mg/kg BW of N-nitroso-N-methylurea (NMU) at 50, 80 and 110 days old. The neoplastic process and the effect of tamoxifen treatment was examined in non-diabetic and diabetic rats. The latency period, NMU-induced tumour incidence and the number of tumours per rat in diabetic rats versus controls were 117 +/- 7 days versus 79 +/- 9 days (P < 0.001); 93% versus 95% (NS); and 5.2 +/- 1.6 versus 2.7 +/- 0.5 (P < 0.02). A more benign histological pattern for tumours in diabetic animals was observed. Mammary tumours in diabetic rats grew more slowly than in controls. Tamoxifen (1 mg/kg/day) treated diabetic rats showed tumour regression in 67% of NMU-induced mammary tumours versus 53% in controls (NS). Our results show that tumour progression seems to be affected by diabetes in this experimental model. We suggest this is the result of changes to insulin-like growth factors and their receptors, which occur in diabetics, and our future research will examine this hypothesis.
authors.affiliation: Laboratorio de Radiosótopos, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
authors.forename: C
authors.initials: C
authors.lastname: Cocca
authors.forename: G
authors.initials: G
authors.lastname: Martin
authors.forename: E
authors.initials: E
authors.lastname: Rivera
authors.forename: C
authors.initials: C
authors.lastname: Davio
authors.forename: G
authors.initials: G
authors.lastname: Cricco
authors.forename: B
authors.initials: B
authors.lastname: Lemos
authors.forename: C
authors.initials: C
authors.lastname: Fitzsimons
authors.forename: A
authors.initials: A
authors.lastname: Gutierrez
authors.forename: E
authors.initials: E
authors.lastname: Levin
authors.forename: R
authors.initials: R
authors.lastname: Levin
authors.forename: M
authors.initials: M
authors.lastname: Croci
authors.forename: R M
authors.initials: RM
authors.lastname: Bergoc
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D002273:Carcinogens / Q000633:toxicity; D002455:Cell Division; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000150:complications* / Q000473:pathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000473:pathology; D005260:Female; D007328:Insulin / Q000097:blood; D008325:Mammary Neoplasms, Experimental / Q000097:blood / Q000209:etiology* / Q000473:pathology; D008770:Methylnitrosourea / Q000633:toxicity; D051381:Rats; D013311:Streptozocin; D013629:Tamoxifen / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D016588:Anticarcinogenic Agents; D002273:Carcinogens; D007328:Insulin; D013629:Tamoxifen; D013311:Streptozocin; D008770:Methylnitrosourea