A novel function of geranylgeraniol in regulating testosterone production.

Isoprenoids play widely differing roles in various physiological processes in animals and plants. Geranylgeraniol (GGOH) is an isoprenoid found in plants, and is an important metabolic derivative in the isoprenoid/cholesterol synthesis pathway. Earlier studies focused on GGOH's ability to improve the side effects of bisphosphonate therapy by regulating the mevalonate pathway.

Geranylgeraniol enhances testosterone production via the cAMP/protein kinase A pathway in testis-derived I-10 tumor cells.

Testosterone levels in men decrease with age; this decline has been linked to various diseases and can shorten life expectancy. Geranylgeraniol (GGOH) is an isoprenoid found in plants that plays an important role in several biological processes; however, its role in steroidogenesis is unknown. Here, we report that GGOH enhances the production of testosterone and its precursor progesterone in testis-derived I-10 tumor cells.

Menaquinone-4 enhances testosterone production in rats and testis-derived tumor cells.

Background: Vitamin K is essential for the posttranslational modification of various Gla proteins. Although it is widespread in several organs, including the testis, the function of vitamin K in these organs is not well characterized. In this study, we investigated the function of vitamin K in the testis and analyzed its role in steroidogenesis.

Dietary vitamin K alleviates the reduction in testosterone production induced by lipopolysaccharide administration in rat testis.

Vitamin K is essential for the posttranslational modifications of blood coagulation factors and proteins present in the bone matrix. Vitamin K is distributed not only in the liver and bones but is also abundant in the brain, kidney, and gonadal tissues. However, the function of extra-hepatic/bone vitamin K has not been fully elucidated.