The effect of ginsenoside on the endocrine glands in rats was studied with radioimmunoassay (RIA) and electron microscopy. Ginsenoside was injected intra-peritoneally for 5 successive days in a dosage of 100 mg/kg weight per day.The animals were killed on the 6 th day.Comparing with the control, the concentration of serum growth hormone (GH) and follicle-stimulating hormone (FSH) were increased significantlyj the thyroid-stimulating hor mone (TSH) , triiodothyronine (T3) and tetraiodothyronine (T4)were decreased markedly) the luteinizing hormone (LH) and cortisol showed no evident change. Electron microscopy revealed that in pars distalis of the pituitary gland, the somatotrophs possessed highly developed rough endoplasmic reticuli or plenty of granules, the gonadotrophs contained vesicular rough endoplasmic reticuli, indicating both were in active secretory phase.Whereas, the follicular epithelial cells of the thyroid appeared functionally inactive.The results demonstrate that ginsenoside exerts a stim The effect of ginsenoside on the endocrine glands in rats was studied with radioimmunoassay (RIA) and electron microscopy. Ginsenoside was injected intra-peritoneally for 5 After days in a dosage of 100 mg/kg weight per day. The animals were killed on the 6 Th day.Comparing with the control, the concentration of serum growth hormone (GH) and follicle-stimulating hormone (FSH) were increased significantlyj the thyroid-stimulating hor mone (TSH), triiodothyronine (T3) and tetraiodothyronine (T4)were significantly markedly ) the luteinizing hormone (LH) and cortisol showed no evident change. Electron microscopy revealed that in pars distalis of the pituitary gland, the somatotrophs possessed highly developed rough endoplasmic reticuli or plenty of granules, the gonadotrophs contained vesicular rough endoplasmic reticuli, indicating both were In active secretory phase.Whereas, the follicular epithelial cells of the thyroid appear functionally inactive.The results demonstrate that ginseno Side exerts a stim