EFFECTS OF DIFFERENT TYPES OF ISOCALORIC PARENTERAL NUTRIENTS ON FOOD-INTAKE AND METABOLIC CONCOMITANTS

Whether spontaneous food intake (SFI) is controlled by infused nutrien t type or its caloric content, irrespective of nutrient type, was inve stigated. Rats were infused for 4 days with isocaloric solutions of di fferent nutrient type but sharing the same intermediary metabolic oxid ative pathway, providing 25% of daily caloric needs. One parenteral so lution was a glucose, fat and amino acid mix (TPN-25%); the other prov ided ketone bodies (TRI-3.5%). Effects of parenteral infusions on SFI and metabolic concomitants were compared and contrasted to that in a g roup of orally fed rats. Both infusions reduced SFI by 50%. Rats recei ving TRI-3.5% had lower blood glucose and insulin concentrations, but increased hepatic glycogen content compared to TPN-25% or orally fed r ats. No differences in hepatic triglycerides occurred between the thre e groups. However, serum free fatty acids were significantly lower in TRI-3.5% and in TPN-25% groups vs. fed rats. Data indicate food intake suppression is mediated by caloric content rather than nutrient type, suggesting that a mediator of SFI regulation could be at the citric a cid cycle lever.