Effect of dietary restriction on the response of alpha 2-macroglobulin during an acute phase response

The effects of aseptic abscesses induced by subcutaneous injections of turpentine (5 mL/kg body weight) on the acute-phase protein response (alpha 2-macroglobulin, alpha 2-M) and on the circulating albumin and total protein concentrations were assessed in young rats that were made malnourished by restricting dietary intake to an extent that either impaired growth (60% of normal intake) or caused weight loss (0% to 45% of normal intake). The measurements were obtained daily during a period of 4 days in malnourished rats that had lost about 25% body weight but had maintained a stable weight thereafter, or in rats that had lost about 12% body weight and were continuing to lose weight at various rates at the time of the turpentine injection. In animals that were injected while they maintained a stable weight after losing about 25% body weight, the alpha 2-M response was attenuated fourfold to eightfold compared with control animals (the area under the 4-day alpha 2-M curve in control rats was 23.3 +/- 2.3 g/L/d). In the depleted animals that were injected while they were actively losing weight (approximately 12.5% weight loss), the attenuation of the alpha 2-M response was related to the rate of weight loss or to the extent of dietary restriction (area under the 4-day alpha 2-M curve ranged from 5.7 +/- 1.4 g/L/d in animals receiving 15% restricted diet to 15.6 +/- 1.5 g/L/d in animals receiving the 45% restricted diet).(ABSTRACT TRUNCATED AT 250 WORDS)