Objective:To investigate the effect of somatostatin (SST) analog octreotide (OCT) in antagonizing the maladjustment of sexual hormones homeostasis induced by tamoxifen(TAM) in rat.Methods:Eight weeks after DMBA(a single dose 100mg/kg body weight by subcutaneous injection) application

the female Wistar rats were randomized to control and treatment groups.Rats in treatment groups underwent TAM(1mg/kg 5 times weekly for 14 weeks by subcutaneous injection)

OCT(0.1mg/kg bid for 14 weeks by subcutaneous injection)

or the combination of both.The levels of sexual hormones (estradiol

progesterone

prolactin

follicle stimulating hormone

luteinizing hormone) were assessed by enzyme immunoassay(EIA).Results:The levels of estradiol and progesterone in serum were remarkably higher in TAM group(21.69pg/ml

6.14ng/ml) than in control group(16.92pg/ml

4.13ng/ml) respectively(P<0.05

P<0.01)

and there was no significant difference between OCT+TAM group(14.58pg/ml

3.88ng/ml) and control group.The prolactin concentrations in serum in the three treatment groups were lower than in control group(P<0.05

P<0.01).Conclusion:OCT can antagonize the effect of TAM to ascend the level of endogenous estrogen

and abolish the ill-effects resulting from maladjustment of sexual hormones homeostasis.