OBJECTIVETo study the changes of hypothalamus-pituitary-ovary (HPO) axis of senescence accelerated mice (SAM) model in their aging process and the modulatory effect of Liuwei Dihuang decoction (LW) on the changes.

METHODSUsing vaginal smear to test the estrous cycle of animal; using radioimmunoassay to determine serum levels of estradiol (E2), and beta-endorphin (beta-EP) and substance P (SP) in hypothalamus; and the western bloting technique was adopted to quantify the level of luteinizing hormone (LH) in pituitary and estradiol receptor alpha (ER alpha) in pituitary and ovary.

RESULTSThe estrous cycle and diestrus were significantly prolonged as SAMP8 aged, the concentration of serum E2 was lower, pituitary LH was higher in the SAMP8 than those in SAMR1. Content of beta-Ep and SP in hypothalamus gradually lowered during aging, SP content lowered after a transient increasing, and ER alpha expression lowered significantly. LW could significantly shorten the diestrus, increase weight of ovary, elevate serum E2 level, significantly reduce the LH level in pituitary, increase beta-EP content in hypothalamus and ER alpha expression in ovary, but significantly lower SP content in hypothalamus. Oral administration of estrogen could increase serum E2, beta-EP and SP content in hypothalamus and ER alpha expression in pituitary, but lower LH level in pituitary, weight of ovary and ER alpha level in ovary.

CONCLUSIONSAMP8, in the aging process, develops a progressive HPO axis functional disturbance, it is closely related with the change of levels of peptide neuro-mediator in hypothalamus and change of ER alpha level in ovary. LW could improve or modulate the HPO axis functional disturbance in SAMP8.