Changes in glucose tolerance and leptin responsiveness of rats offered a choice of lard, sucrose, and chow

Ruth Babette Harris, John W. Apolzan

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Rats offered chow, lard, and 30% sucrose solution (choice) rapidly become obese. We tested metabolic disturbances in rats offered choice, chow+lard, or chow+30% sucrose solution [chow+liquid sucrose (LS)] and compared them with rats fed a composite 60% kcal fat, 7% sucrose diet [high-fat diet (HFD)], or a 10% kcal fat, 35% sucrose diet [low-fat diet (LFD)]. Choice rats had the highest energy intake, but HFD rats gained the most weight. After 23 days carcass fat was the same for choice, HFD, chow+lard, and chow+LS groups. Glucose clearance was the same for all groups during an intraperitoneal glucose tolerance test (GTT) on day 12, but fasting insulin was increased in choice, LFD fed, and chow+LS rats. By contrast, only choice and chow+LS rats were resistant to an intraperitoneal injection of 2 mg leptin/kg on day 17. In experiment 2 choice rats were insulin insensitive during an intraperitoneal GTT, but this was corrected in an oral GTT due to GLP-1 release. UCP-1 protein was increased in brown fat and inguinal white fat in choice rats, and this was associated with a significant increase in energy expenditure of choice rats during the dark period whether expenditure was expressed on a per animal or a metabolic body size basis. The increase in expenditure obviously was not great enough to prevent development of obesity. Further studies are required to determine the mechanistic basis of the rapid onset of leptin resistance in choice rats and how consumption of sucrose solution drives this process.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume302
Issue number11
DOIs
StatePublished - Jun 1 2012

Fingerprint

Leptin
Sucrose
Glucose
High Fat Diet
Glucose Tolerance Test
Fat-Restricted Diet
Fats
Health Expenditures
lard
Insulin
Diet
White Adipose Tissue
Glucagon-Like Peptide 1
Brown Adipose Tissue
Groin
Body Size
Energy Intake
Intraperitoneal Injections
Energy Metabolism
Fasting

Keywords

  • Dietary sucrose
  • Energy expenditure
  • Leptin resistance
  • UCP-1

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

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abstract = "Rats offered chow, lard, and 30{\%} sucrose solution (choice) rapidly become obese. We tested metabolic disturbances in rats offered choice, chow+lard, or chow+30{\%} sucrose solution [chow+liquid sucrose (LS)] and compared them with rats fed a composite 60{\%} kcal fat, 7{\%} sucrose diet [high-fat diet (HFD)], or a 10{\%} kcal fat, 35{\%} sucrose diet [low-fat diet (LFD)]. Choice rats had the highest energy intake, but HFD rats gained the most weight. After 23 days carcass fat was the same for choice, HFD, chow+lard, and chow+LS groups. Glucose clearance was the same for all groups during an intraperitoneal glucose tolerance test (GTT) on day 12, but fasting insulin was increased in choice, LFD fed, and chow+LS rats. By contrast, only choice and chow+LS rats were resistant to an intraperitoneal injection of 2 mg leptin/kg on day 17. In experiment 2 choice rats were insulin insensitive during an intraperitoneal GTT, but this was corrected in an oral GTT due to GLP-1 release. UCP-1 protein was increased in brown fat and inguinal white fat in choice rats, and this was associated with a significant increase in energy expenditure of choice rats during the dark period whether expenditure was expressed on a per animal or a metabolic body size basis. The increase in expenditure obviously was not great enough to prevent development of obesity. Further studies are required to determine the mechanistic basis of the rapid onset of leptin resistance in choice rats and how consumption of sucrose solution drives this process.",
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