Aim: 

To study the interaction of the dietary protein (lactalbumin) with recombinant human growth hormone (rhGH) treatment on the atherogenic profile and liver lipid peroxidation (LPO) during aging in female BALB/c mice.

Methods: 

24 female BALB/c mice (aged 18-months) were administered either rhGH (2 mg/g BW) or saline (NaCl 9 g/l) during 30 days and were fed medium protein (MP: 14%) or control (20%) diets. Body and abdominal fat, plasma leptin concentration and lipid profile, and hepatic lipid peroxidation (LPO) were determined.

Results: 

Both rhGH treatment and MP diet decreased abdominal fat depot (45%) revealing their lypolitic effects. The direct relationship between leptin levels and body fat (%) was confirmed by a high determination coefficient (r²=0.719). rhGH treatment was anti-atherogenic; but the MP diet induced atherogenicity abolishing the hormone treatment effect. Thus, rhGH decreased total cholesterol, LDL+VLDL, and the atherogenic index only in control diet mice (decreased 10% compared to saline); whereas the MP diet increased the atherogenic index (46% in saline and 68% in rhGH mice), also decreasing HDL-cholesterol (45%) and total cholesterol (17%). Treatment with rhGH decreased liver LPO (18%, irrespective of diet). This effect was maintained independently of the enhanced LPO increase provoked by feeding MP diet (38%, irrespective of treatment).

Conclusion: 

In old female BALB/c mice, rhGH treatment induces both anti-atherogenic and anti-lipid peroxidation effects. Feeding a protein-restricted diet eliminates the first effect, but maintains the anti-LPO effect of rhGH treatment.