The aim of this study was to investigate the effect of luteinizing hormone (LH) surge on expression of nerve growth factor (NGF), trkA, p75 and inhibin α-subunit in ovarian interstitial cells of golden hamsters after human chorionic gonadotropin (hCG) treatment. NGF, two NGF receptors (trkA, p75) and inhibin α-subunit were immunolocalized by immunohistochemistry, and gonadotropins, steroid hormones and immunoreactive (ir-) inhibin concentrations were measured by radioimmunoassay. Stronger positive staining of NGF, trkA and p75 were found in interstitial cells at 6, 12 and 18 h after hCG injection in the treated group compared with the control groups. Inhibin α-subunit staining was found in interstitial cells at 12 and 18 h after hCG injection in the treatment group, but not in the control group. Plasma concentrations of progesterone increased significantly from 6 to 18 h after hCG treatment, whereas plasma concentrations of estradiol-17β significantly decreased compared with the control group. An increased plasma concentration of FSH and decreased concentrations of ir-inhibin from 6 to 18 h after hCG treatment verified the negative relationship. There were no significant changes in the concentrations of LH in the hCG-treated group. In contrast, the typical preovulatory LH surge was found at 1700 h on day 4 (proestrus) in the control group. These results suggested that LH surge can induce expression of NGF, trkA, p75 and inhibin α-subunit in ovarian interstitial cells and that NGF, trkA, p75 and inhibin α-subunit may have a paracrine or autocrine role in modulation of ovarian interstitial cell function in golden hamsters.