Long-term administration of a sucrose-rich diet to normal rats: Relationship between metabolic and hormonal profiles and morphological changes in the endocrine pancreas

The aim of the present investigation was to study normal rats fed a sucrose-rich diet (SRD) for a prolonged period (up to 30 weeks) (1) to obtain additional data on the hormonal and metabolic patterns induced by this treatment and (2) to provide information on changes taking place in the pancreatic islet cell populations. We found that long-term feeding with a SRD resulted in a steady state of hypertriglyceridemia and hyperglycemia in which insulin levels remained unchanged and unable to compensate for the increased demands of the developing metabolic changes. The endocrine pancreas showed a significant increase of both islet number and B-cell area, as well as changes in the profile of islet cell distribution. However, these changes were not accompanied by an increase in the pancreatic content of immunoreactive insulin (IRI). It may therefore be postulated that the newly emerged B-cell mass has some sort of derangement with the increased insulin demand resulting from insulin resistance induced by the long-term SRD feeding. Thus, feeding a SRD to normal rats may prove to be an attractive animal model for studying the role of environmental nutritional factors in the unsettled issue of the relationship between insulin resistance and relative insulin deficiency. The model might provide key information for understanding the pathophysiology of human diseases such as type II diabetes, dyslipidemia, and a number of entities included in so-called syndrome X.