RETRACTED: The production of hydrogen sulfide is regulated by testosterone and S-adenosyl-L-methionine in mouse brain (Retracted Article. See vol 93, pg 1633, 2005)

Hydrogen sulfide (H-2 S) is endogenously produced in the brain from l-cysteine by the enzyme cystathionine beta-synthase (CBS) and functions as a neuromodulator in the brain. H-2 S selectively enhances NMDA receptor-mediated responses and alters hippocampal long-term potentiation (LTP). The production of H-2 S is regulated by Ca2+ /calmodulin-mediated pathways and is enhanced in response to neuronal excitation. In addition to this fast regulation, we describe here a slower form of the regulation of H-2 S production by testosterone and S -adenosyl-l-methionine (SAM), a CBS activator. Endogenous H-2 S in the mouse brain increases after birth, reaches a maximum level at 8 weeks and then decreases. Female brain contains less H-2 S than male brain at each age. A single administration of testosterone to female mice increases the endogenous H-2 S and SAM, which reach levels similar to those of male mice. In contrast, castration of male mice decreases the levels of testosterone, SAM and H-2 S in the brain. Administration of SAM once a day for 3 days increases the brain H-2 S without significantly changing the testosterone level. These observations suggest that testosterone can regulate the brain H-2 S level via changing the level of SAM.