Incorporation of β-sitosterol into the membrane prevents tumor necrosis factor-α-induced nuclear factor-κB activation and gonadotropin-releasing hormone decline.

It has been demonstrated that hypothalamus has a programmatic role in aging development, and this role of hypothalamus is mediated by nuclear factor-κB (NF-κB)-directed gonadotropin-releasing hormone (GnRH) decline. β-Sitosterol (BS), one of the most common phytosterols in the diet, is able to inhibit pro-inflammatory NF-κB signaling. It has been demonstrated that dietary BS can enter the brain and accumulates in brain cell membranes. However, it is unknown whether and how membrane BS affects GnRH release. Using GT1-7 cells, a cell line of GnRH neurons, this study investigated if membrane BS had an influence on GnRH release. It was found that incorporation of BS into the membrane could prevent tumor necrosis factor-α (TNF-α)-induced GnRH decline. The underlying basis involves inhibition of NF-κβ activation via estrogen receptor (ER)-mediated inhibition of inhibitor of nuclear factor κB (Iκβ) processing. These results extend existing data regarding the beneficial effects of BS, and suggest the use of BS-enriched foods as anti-aging nutrients.