ABSTRACT
Objective To investigate the effects of female sex hormones in cow's milk on metabolism of blood lipid in young male rats.Methods Forty-eight male Sprague-Dawley rats aged 21 days old were assigned randomly to 4 groups,each containing 12 rats,and fed with quantitative milk from postpartum cow,milk from pregnant cow,commercial whole milk and artificial milk,respectively.Serum total cholesterol (TC),triacylglyeriol(TG),high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C) and urinary creatinine (Cr) were determined with automatic biochemical analyzer.Serum progesterone(P4)and urinary free estriol(UFE3) were determined with immunochemiluminometric assays after all rats were killed at 53 days old.SPSS 13.0 software was used to analyze the data.Results Total estradiol and P4 were 1 189.66 pmol/L,833.98 pmol/L,588.17 pmol/L,286.48 pmol/L and 9.76 nmol/L,10.18 nmol/L,2.83 nmol/L,0.92 nmol/L in milk from pregnant cow,commercial whole milk,milk from postpartum cow and artificial milk groups,respectively.Serum TC were respectively(1.78?0.29) mmol/L,(1.94?0.20) mmol/L,(2.10?0.28) mmol/L and (2.11?0.22) mmol/L in pregnant milk,commercial whole milk,postpartum milk and artificial milk groups,and TC in pregnant milk group was lower than that in postpartum milk group or artificial milk group(P0.05).Conclusion Milk from pregnant cow may reduce serum TC in young male SD rats,which may be related to the conjoined effect of estradiol and P4.