Hydrogen Sulphide Production in Healthy and Ulcerated Gastric Mucosa of Rats

Hydrogen sulphide (H(2)S) is produced endogenously via two enzymes dependent on pyridoxal phosphate (PLP): cystathionine beta-synthase (CBS, EC 4.2.1.22), cystathionase γ-liase (CTH, EC 4.4.1.1), and a third, 3-mercaptopyruvate sulfurtransferase (MPST, EC 2.8.1.2). H(2)S strengthens the defence mechanisms of the gastric mucosal barrier, and plays an important role in gastroprotection, including the increased resistance to damage caused by various irritants and non-steroidal anti-inflammatory drugs. The study was conducted to determine the role of H(2)S in ulcerated gastric mucosa of rats caused by immobilization in cold water (WRS). The activity and expression of γ-cystathionase, cystathionine β-synthase, 3-mercaptopyruvate sulfurtransferase, and rhodanese was compared with healthy mucosa, together with H(2)S generation, and cysteine, glutathione, and cystathionine levels. The results showed that the defence mechanism against stress is associated with stimulation of the production of H(2)S in the tissue and confirmed the observed advantageous effect of H(2)S on healing of gastric ulcers. In case of animals pretreated with exogenous sources of H(2)S and NaHS, and some changes observed in the ulcerated gastric mucosa tend to return to values found in the healthy tissue, a finding that is in accordance with the previously determined gastroprotective properties of H(2)S. The results presented in this paper point to the possible role of rhodanese in H(2)S production in the gastric mucosa of rats, together with the earlier mentioned three enzymes, which are all active in this tissue.