A cross-sectional and short-term longitudinal characterisation of NIDDM in Psammomys obesus.
The present study was undertaken to examine the cross-sectional and short-term longitudinal changes in glucose and insulin concentrations as well as measure the enzymatic activity of PEPCK and glycogen synthase in our Psammomys obesus colony. In the cross-sectional study, blood samples were taken from one group of animals at 19 weeks of age (n = 37) in the fed state and following a 4-h fast. In a separate group of 19-week-old animals (n = 69), samples were taken 1 h following an OGTT (1 g/kg body weight) in Psammomys subjected to a 16-h fast. In the longitudinal study, blood samples were taken from one group of animals in the fed state at 7, 11, 15 and 19 weeks of age. All of the cross-sectional data have described the classic inverted U-shaped curve (Starling's curve of the pancreas) in the relationship between glucose and insulin levels. This trend was also reflected by Psammomys subjected to the OGTT; a mild impairment in glucose tolerance was associated with an increase in the insulin response and a further impairment in glucose tolerance was associated with a reduction in the insulin response. Similar results were obtained following a 4-h fast. The short-term longitudinal glucose and insulin data revealed that of the 37 animals examined over the 12-week period, 16 progressed along the inverted U-shaped curve described by the cross-sectional data. Of the other animals, 8 remained unchanged, 7 were unclassifiable and 6 hyperglycaemic Psammomys developed normoglycaemia at the expense of elevated insulin levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Barnett
M
M
School of Nutrition and Public Health, Deakin University, Victoria, Australia.
Collier
G R
GR
Collier
F M
FM
Zimmet
P
P
O'Dea
K
K
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004195:Disease Models, Animal; D005849:Gerbillinae; D005951:Glucose Tolerance Test; D006006:Glycogen Synthase / Q000378:metabolism; D006943:Hyperglycemia / Q000378:metabolism; D007328:Insulin / Q000097:blood; D008099:Liver / Q000201:enzymology; D008137:Longitudinal Studies; D008297:Male; D009132:Muscles / Q000201:enzymology; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism
D001786:Blood Glucose; D007328:Insulin; D006006:Glycogen Synthase; D010729:Phosphoenolpyruvate Carboxykinase (GTP)