Gastric Emptying Dynamics and Glycemic Responses in Obese and Diabetic SHR/N-cp Rat Models: Implications for Understanding Type II Diabetes | Chapter 13 | Medical Science: Trends and Innovations Vol. 12

Obesity and overweight conditions, separately or in concert with Type II Diabetes mellitus (T2DM), are now occurring globally with an alarming incidence throughout much of industrialized society. Disordered gastric physiology is a common observation in diabetes, including processes of both rapid emptying early in T2DM and in gastroparesis in later stages of both T2DM and Type 1, insulin-dependent diabetes. The purpose of the present study was to characterize the expression of the obese and obese+T2DM traits in the development of T2DM and its impact on gastric emptying and glycemic parameters when reared under identical conditions of diet and environment. To determine the characteristics of gastric emptying in lean, obese, and obese diabetic rats, measures of oral glucose tolerance (OGT) were determined, and glycemic parameters of obesity and type II diabetes (T2DM) were measured. The study was approved by the Institutional Animal Care and Use Committee. Fasting plasma Insulin, amylin, and markers of insulin resistance were greater in obese than in lean littermates and increased further in both young and old obese+T2DM rats. The oral glucose tolerance and glucose areas under the curve (AUCglc) were modestly impaired in obese LA/Ntul//-cp rats, with only a modest increment in the early phase (0 to +30 min post ingestion) of luminal glucose uptake. The OGT in obese+T2DM rats was markedly impaired, with additional progression in aging. The fractional AUCglc from 0 to+30 minutes was significantly increased in the obese+T2DM rats, and the acceleration in initial glycemic response of OGT was increased 6-fold in young T2DM rats and remained greatly elevated thereafter. The initial and late post-absorptive glycemic phase of the OGT in old obese individuals was greater than in younger obese T2DM. These results are consistent with epigenetic expression of obesity and obesity+T2DM and with dysregulation in the kinetics of gastric emptying analogous to Dumping Syndrome or Sirt1 dysregulation in the young obese-T2DM phenotype of the SHR/Ntul//-cp rats and the neurologic onset of gastroparesis in old T2DM SHR/Ntul//-cp rats. The result of this study indicates that the aberrant glycemic responses to a standard OGT in obese and obese-T2DM rats were consistent with accelerated gastric emptying in young obese+T2DM rats, in addition to glycemic responses consistent with the onset of gastroparesis in combination with insulin resistance in older obese+T2DM rats.  Thus, the Obese+T2DM rat is a useful model for the further investigation of the pathophysiology of obesity and T2DM as it occurs in man and animals.

 

Author (s) Details

 

Orien L Tulp
Colleges of Medicine and Graduate Studies, University of Science, Arts and Technology, USA.

 

Please see the book here:- https://doi.org/10.9734/bpi/msti/v12/4872