S-Adenosylhomocysteine hydrolase overexpression in HEK-293 cells: effect on intracellular adenosine levels, cell viability, and DNA methylation.

Background/aims: S-Adenosylhomocysteine hydrolase (AdoHcyase) catalyzes the reversible hydrolysis of S-adenosylhomocysteine (AdoHcy), which is a potent product inhibitor of S-adenosylmethionine (AdoMet)-dependent methyltransferases. While previous studies have shown that AdoHcyase inhibition or deficiency lead to a decreased AdoMet/AdoHcy ratio resulting in impaired transmethylation, the effect of enhanced AdoHcyase activity on AdoMet/AdoHcy metabolism and methylation reactions has not been studied in detail.

Methods: To investigate the effect of enhanced AdoHcyase activity, we generated HEK-293 cell lines stably overexpressing AdoHcyase.

Dopamine D3 receptor mRNA and renal response to D3 receptor activation in spontaneously hypertensive rats.

Defective dopamine receptors may be involved in the development of hypertension. Recently, it has been shown that gene expression and function of the renal dopamine D3 receptor is impaired in salt-sensitive Dahl rats, a model of salt-dependent hypertension. Here, the functional response to D3 receptor activation was investigated in spontaneously hypertensive rats (SHR) and their normotensive Wistar-Kyoto rats (WKY).