Regulation of steroidogenesis by Cordyceps sinensis mycelium extracted fractions with (hCG) treatment in mouse Leydig cells.

The in vitro effect of extracted fractions of Cordyceps sinensis (CS) mycelium on hCG-treated testosterone production from purified normal mouse Leydig cells was examined. Different fractions extracted from CS (F1-water soluble polysaccharide, F2- water soluble protein and F3- poorly water soluble polysaccharide, and protein) were added to Leydig cells with hCG, and the production of testosterone was determined by radioimmunoassay (RIA). Testosterone productions stimulated by hCG in mouse Leydig cells were suppressed by F2 at 10 mg/ml and F3 at doses from 3 to 10 mg/ml, respectively. F2 and F3 at 10 mg/ml did inhibit dbcAMP-stimulated testosterone productions which indicated that F2 and F3 might affect steroidogenesis at the site after the formation of cyclic AMP. Finally, cycloheximide inhibited F2- and F3-treated mouse Leydig cell testosterone production.

Effects of Tremella mesenterica on steroidogenesis in MA-10 mouse Leydig tumor cells.

Tremella mesenterica (TM), a yellow jelly mushroom, has been traditionally used as food and crude medicine to improve several kinds of symptoms in Chinese society for a long time. Recent studies have illustrated that the fractions of fruiting bodies of TM exhibit a significant hypoglycemic activity in diabetic mouse models, which usually suffer from sexual dysfunction. In a previous study, we showed that TM reduced plasma testosterone production in normal rats without any positive effect in diabetic rats. It evolved a question of TM directly regulating Leydig cell steroidogenesis. In this study, MA-10 mouse Leydig tumor cells were treated with vehicle, different dosages of TM with or without human chorionic gonadotropin (hCG 50 ng/ml) to clarify the effects. Results showed that TM at different dosages (0.01-10 mg/ml) did not have any effect on MA-10 cell steroidogenesis (p > 0.05). In the presence of hCG, there was an inhibitory trend that TA suppressed MA-10 cell progesterone production at 3 hr treatment with a statistically significant difference by the 10 mg/ml TM (p < 0.05). In time course effect, TM alone did not have any effect on MA-10 cell steroidogenesis from at 1, 2, 3, 6 and 12 hr (p > 0.05). However, TM did reduce hCG-treated MA-10 cell progesterone production at 1, 2 and 3 hr (p < 0.05), respectively. To determine whether TM would have adverse effects on MA-10 cell steroidogenesis in the presence of hCG, MTT assay and recovery studies were conducted. MTT assay indicated that TM had no effect on surviving cells. In addition, with the removal of TM, and then the addition of hCG (2 and 4 hr), progesterone levels were restored within 4 hr. Taken together, present studies suggested that TM suppressed hCG-treated steroidogenesis in MA-10 cells without any toxicity effect.

Effects of Cordyceps sinensis on testosterone production in normal mouse Leydig cells.

The stimulatory effect of Cordyceps sinensis (CS) on MA-10 mouse Leydig tumor cell steroidogenesis was previously demonstrated in our laboratory. In the present studies, we further determined the effect of CS on steroidogenesis in purified normal mouse Leydig cells. Different concentrations of CS (0.1-10 mg/ml) were added to Leydig cells without or with human chorionic gonadotropin (hCG) (50 ng/ml), and the steroid production was determined by radioimmunoassay (RIA). The results illustrated that CS stimulated normal mouse Leydig cell steroidogenesis in a dose-dependent relationship. CS at 3 mg/ml significantly stimulated testosterone production (p<0.05). Concerning the temporal relationship, CS at 3 mg/ml stimulated maximal testosterone production between 2 to 3 hr. Interestingly, hCG-stimulated testosterone productions were suppressed by CS in a dose-dependent relationship. CS also reduced dbcAMP-stimulated testosterone productions, which indicated that CS affected signal transduction pathway of steroidogenesis after the formation of cyclic AMP. Moreover, cycloheximide inhibited CS-treated mouse Leydig cell testosterone production, suggesting that new protein synthesis was required for CS-stimulated steroidogenesis.

Effects of extracted Cordyceps sinensis on steroidogenesis in MA-10 mouse Leydig tumor cells.

Extracts from the mycelium of Cordyceps sinensis (CS) were tested to determine the in vitro effect on Leydig cell function. MA-10 mouse Leydig tumor cells were used to conduct the experiments. Results showed that progesterone production gradually increased as the dosage of combined water and ethanol extracted CS increased, and there was a statistically significant difference in progesterone production stimulated by 20 mg/ml of CS extracts compared to the control. The combined water and ethanol extracted CS significantly stimulated MA-10 cell steroid production at 12 and 24 h of incubation. In addition, a protein synthesis inhibitor, cycloheximide, did not block the stimulatory effects of CS extracts on MA-10 cell steroid production or total protein expression. Moreover, the expression of steroidogenic acute regulatory (StAR) protein, which is a critical protein for steroidogenesis, stimulated by CS extracts, could not be detected by Western blot analysis. These data indicate that CS extracts might not induce StAR protein and/or other protein expressions to stimulate steroidogenesis in MA-10 mouse Leydig tumor cells.