Abstract
Obese-hyperglycemic mice (obob) were parabiosed with lean littermates and body weight,
blood glucose, serum insulin and triglycerides as well as insulin-sensitivity of diaphragm
muscle and epididymal fat were determined on the 50th postoperative day. Single (non-parabiosed)
mice and lean/lean, obob/obob parabiosed pairs served as controls.
The mortality rate was highest among lean/obob and lowest among lean/lean pairs. The
gain in body weight was also least among both partners of lean/obob pairs. Parabiosis
had a small (lowering) effect on the blood glucose and serum insulin level of lean
mice but it improved markedly the hyperglycemia of parabiotic obob in both obob/obob
and obob/lean pairs; in the latter the serum insulin was also significantly decreased
suggesting an improvement of the animal's sensitivity to insulin.
In vitro studies involving incubation of diaphragm muscle and epididymal fat tissue
in the absence and presence of insulin (1 mU/ml) revealed that while parabiosis had
no effect on the tissue-sensitivity to insulin in lean mice, it increased that of
obob joined with either obese or lean mice. These changes are attributed to the decrease
in body weight of the obese parabiotic mice, probably as a result of a reduced caloric
intake. Thus, limiting the caloric intake of the obob and lean mice for 5 days brought
about changes similar to those caused by parabiosis.
Key words
Parabiosis - Insulin Resistance - Obese-Hyperglycemic Mice - Hyperglycemia - Obesity
- Caloric Restriction
