A long-term high-carbohydrate diet causes an altered ontogeny of pancreatic islets of Langerhans in the neonatal rat.
Neonatal rats fed a high-carbohydrate (HC) formula by gastrostomy are hyperinsulinemic but normoglycemic. We determined whether HC formula altered pancreatic islet cell ontogeny. Rats were reared from d 4 on an HC formula or a high-fat formula, or were allowed to suckle naturally, and the pancreata were examined histologically from animals < or =24 d of age. The mean area of individual islets was reduced, but islet number was increased in HC rats compared with mother-fed or high fat-fed animals, which were similar. Islets from HC animals were relatively deficient in alpha cells and had a greater incidence of islet cells with fragmented DNA, indicative of apoptosis. Ductal epithelium, a source of new islets by neogenesis, had a greater incidence of cells staining immunopositive for proliferating cell nuclear antigen, a marker of cell replication, and a lower incidence of apoptosis. The islet cell mitogen and survival factor, IGF-II, had a reduced mRNA expression in whole pancreas from HC animals. The relative area of islet cells demonstrating IGF-II immunoreactivity was reduced in HC-fed rats versus controls, although a greater percentage of ductal epithelial cells were immunopositive. HC formula alters islet cell ontogeny by affecting islet size and number, which may be linked to an altered IGF-II expression.
Petrik
J
J
Lawson Research Institute, St. Joseph's Health Centre, London, Ontario N6A 4V2, Canada.
Srinivasan
M
M
Aalinkeel
R
R
Coukell
S
S
Arany
E
E
Patel
M S
MS
Hill
D J
DJ
D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism; D007515:Islets of Langerhans / Q000196:embryology* / Q000378:metabolism; D011247:Pregnancy; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley
D004040:Dietary Carbohydrates; D018809:Proliferating Cell Nuclear Antigen; D007335:Insulin-Like Growth Factor II