Effects of diet restriction on insulin-sensitive phosphodiesterase in rat fat cells.
Effects of insulin on insulin-sensitive phosphodiesterase were investigated using fat cells from diet-restricted rats. The enzyme activities in diet-restricted rats were higher in case of 0 to 30 nmol/L insulin concentrations than in ad lib fed rats. In fat cells from the diet-restricted rats, the curves shifted to the left and half-maximum stimulation was obtained at 0.04 nmol/L, compared to that of 0.18 nmol/L in ad lib fed rats. Specific binding of insulin for fat cells from diet restricted and ad lib fed rats was 6.0% and 5.4%/2 X 10(5) cells, respectively. However when insulin binding was expressed per unit cell surface area, it was significantly increased in fat cells from diet-restricted rats compared with that from control rats. These results suggest that the insulin effector system related to the phosphodiesterase activation is improved in fat cells from diet-restricted rats, in particular, sensitivity to insulin. These increases in sensitivity to the phosphodiesterase are possibly due to improvements of insulin receptor binding.
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000273:Adipose Tissue / Q000201:enzymology* / Q000378:metabolism; D000818:Animals; D004038:Diet, Reducing; D002149:Energy Intake; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000378:metabolism
D007328:Insulin; D011972:Receptor, Insulin; D015105:3',5'-Cyclic-AMP Phosphodiesterases