Inhibitory effect of protopanaxatriol ginseng metabolite M4 on the production of corticosteroids in ACTH-stimulated bovine adrenal fasciculata cells

Relationship between Ca2+ and cAMP as second messengers in ACTH-induced cortisol production in bovine adrenal fasciculata cells

In adrenal fasciculata cells stimulated by ACTH, Ca2+ and cAMP play indispensable roles as second messengers in cortisol production. However, whether their second messengers cooperatively or independently participate in steroid production remains unclear. We focused on the roles of Ca2+ and cAMP in cortisol production in bovine adrenal fasciculata cells stimulated by ACTH for a relatively short period (1 h). Incubation of the cells with 100 pM ACTH in Ca2+-containing (normal) medium for 1 h increased cortisol production without affecting cAMP content. In contrast, treatment of the cells with the peptide at a higher concentration (1 nM) significantly augmented both cortisol production and cAMP content. However, ACTH did not increase either of them in the Ca2+-free medium. ACTH rapidly increased the intracellular free Ca2+ concentration ([Ca2+]i) in the normal medium, but did not influence [Ca2+]i in the Ca2+-free medium, indicating that ACTH caused Ca2+ influx into the cells. ACTH-induced Ca2+ influx and cortisol production were suppressed by a voltage-sensitive L-type Ca2+ channel blocker but not by a T-type, N-type, or P-type Ca2+ channel blocker. In contrast, dibutyryl cAMP, a cell-permeable cAMP analog, greatly enhanced cortisol production in the normal or Ca2+-free medium and slowly caused Ca2+ influx into the cells. These results strongly suggest that Ca2+, as a second messenger, is more critical than cAMP for cortisol production. However, both second messengers jointly participate in the production in adrenal fasciculata cells stimulated by ACTH.

Advances on hormone-like activity of Panax ginseng and ginsenosides

Traditional Chinese medicine (TCM) has been paid much attentions due to the prevention and treatment of steroid hormone disorders. Ginseng, the root of Panax ginseng C. A. Meyer (Araliaceae), is one of the most valuable herbs in complementary and alternative medicines around the world. A series of dammarane triterpenoid saponins, also known as phytosteroids, were reported as the primary ingredients of Ginseng, and indicated broad spectral pharmacological actions, including anti-cancer, anti-inflammation and anti-fatigue. The skeletons of the dammarane triterpenoid aglycone are structurally similar to the steroid hormones. Both in vitro and in vivo studies showed that Ginseng and its active ingredients have beneficial hormone-like role in hormonal disorders. This review thus summarizes the structural similarities between hormones and dammarane ginsenosides and integrates the analogous effect of Ginseng and ginsenosides on prevention and treatment of hormonal disorders published in recent twenty years (1998-2018). The review may provide convenience for anticipate structure-function relationship between saponins structure and hormone-like effect.

Ginsenoside Rd attenuates ACTH-induced corticosterone secretion by blocking the MC2R-cAMP/PKA/CREB pathway in Y1 mouse adrenocortical cells

BACKGROUND

Higher levels of glucocorticoids (GCs), and impaired regulation of the hypothalamic-pituitary-adrenal (HPA) axis may cause or exacerbate the occurrence of metabolic and psychiatric disorders. It has been reported that ginseng saponin extract (GSE) has an inhibitory effect on the hyperactivity of the HPA axis induced by stresses and increased corticosterone level induced by intraperitoneal injection of adrenocorticotrophic hormone (ACTH) in mice. However, the molecular mechanisms by which GSE and its active ginsenosides inhibit corticosterone secretion remain elusive.

MAIN METHODS

Y1 mouse adrenocortical cells were treated with ACTH for up to 60 min to establish a cell model of corticosterone secretion. After treatment with different concentrations of GSE or ginsenoside monomers for 24 h prior to the addition of ACTH, analyses of cAMP content, PKA activity, and the levels of steroidogenesis regulators, melanocortin-2 receptor (MC2R), and melanocortin-2 receptor accessory protein (MRAP) in ACTH-induced Y1 cells were performed.

RESULTS

We demonstrated that GSE inhibits ACTH-stimulated corticosterone production in Y1 cells by inhibiting factors critical for steroid synthesis. Ginsenoside Rd, an active ingredient of GSE, inhibits corticosterone secretion in the cells and impedes ACTH-induced corticosterone biosynthesis through down-regulation of proteins in the cAMP/PKA/CREB signaling pathway. In addition, Western blot and qPCR analyses showed that ginsenoside Rd attenuated the induction of MC2R and MRAP by ACTH.

CONCLUSION

Our findings indicate that ginsenoside Rd inhibits ACTH-induced corticosterone production through blockading the MC2R-cAMP/PKA/CREB pathway in adrenocortical cells. Overall, this mechanism may represent an important therapeutic option for the treatment of stress-related disorders, further supporting the pharmacological benefits of ginseng.

Steroids in traditional Chinese medicine: what is the evidence?

Local healthcare providers often question the possible steroidal activity of traditional Chinese medicine (TCM) herbs or herbal products and implicate them as a cause for adrenal insufficiency or Cushing's syndrome in patients with a history of TCM intake. We conducted a comprehensive database search for evidence of potential glucocorticoid, mineralocorticoid, androgenic or oestrogenic activity of herbs or herbal products. Overall, there are not many herbs whose steroidal activity is well established; among these, most cases were based on preclinical studies. Liquorice root may cause pseudoaldosteronism through interference with the steroidogenesis pathway. Although ginseng and cordyceps have some in vitro glucocorticoid activities, the corroborating clinical data is lacking. Deer musk and deer antler contain androgenic steroids, while epimedium has oestrogenic activity. On the other hand, adulteration of herbal products with exogenous glucocorticoids is a recurrent problem encountered locally in illegal products masquerading as TCM. Healthcare providers should stay vigilant and report any suspicion to the relevant authorities for further investigations.

Effects of Korean red ginseng extract on behavior in children with symptoms of inattention and hyperactivity/impulsivity: a double-blind randomized placebo-controlled trial

Abstract Objective: There is evidence that Korean red ginseng (KRG) can reduce the production of the adrenal corticosteroids, cortisol, and dehydroepiandrosterone (DHEA), and thus may be a viable treatment for attention-deficit/hyperactivity disorder (ADHD). The present randomized double-blind placebo-controlled clinical trial tested the effect of KRG on children with ADHD symptoms.

METHODS

Subjects 6-15 years, who satisfied the inclusion criteria and had ADHD symptoms, were randomized into a KRG group (n=33) or a control group (n=37). The KRG group received one pouch of KRG (1g KRG extract/pouch) twice a day, and the control group received one pouch of placebo twice a day. At the 8 week point, the primary outcomes were the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for inattention and hyperactivity scale scores, which were measured at baseline and 8 weeks after starting treatment. Secondary outcomes were quantitative electroencephalography theta/beta ratio (QEEG TBR) (measured at baseline and week 8) and salivary cortisol and DHEA levels (measured at baseline and at 4 and 8 weeks).

RESULTS

The baseline characteristics of the KRG and control groups were not statistically different. The mean ages of the KRG and control groups were 10.94±2.26 and 10.86±2.41, respectively. The KRG group had significantly decreased inattention/hyperactivity scores compared with the control group at week 8 (least squared means of the differences in inattention adjusted for baseline scores: -2.25 vs. -1.24, p=0.048; hyperactivity: -1.53 vs. -0.61, p=0.047). The KRG group had significantly decreased QEEG TBR compared with the control group (least squared means of the differences: -0.94 vs. -0.14, p=0.001). However, neither the KRG group nor the control group exhibited significant differences in salivary cortisol or DHEA levels at week 8 compared with the baseline levels. No serious adverse events were reported in either group.

CONCLUSIONS

These results suggest that KRG extract may be an effective and safe alternative treatment for children with inattention and hyperactivity/impulsivity symptoms. Further studies to investigate the efficacy and safety of KRG are warranted.