In the present study

radioimmunoassay (RIA)

RNA dot blot and computer image analysis technique were used to study the influence of electroacupuncture (EA) on the expression of pituitary estrogen receptor mRNA (ER mRNA) and the level of blood estradiol (E2) in the female rats. Four groups of randomly selected female rats were employed in the experiments: intact group (INT)

intact + EA group (INT + EA)

ovariectomized group (OVX) and ovariectomized +EA group (OVX + EA). The results indicate that the blood E2 level of OVX is significantly lower than that of INT (P < 0 . 01) and the grey density of hybridization dots in the INT is 64. 72±19. 71 and that in the OVX is 21. 82±4.72

which is significantly decreased compared with that in the INT (P <0.01). The level of blood E2 in the OVX + EA is markedly increased compared with that in the OVX (P < 0.01). The grey density of hybridization dots in the OVX + EA is 37. 61±5. 26

which is significantly higher than that in the OVX (P <0.01). There is no significant difference between the levels of E2 in the INT and INT + EA (P >0.05). The grey density of hybridization dots in the INT + EA is 64. 81±8.03

being no significant difference compared with that in the INT (P>0.05). The results suggest that EA may increase the blood E2 level and affect the pituitary ER mRNA expression in the ovariectomized rats

which may play a role in the normalization of the dysftinction of hypothalamic-pituitary-ovarian axis by EA.