DECREASED PHENYLETHANOLAMINE-N-METHYLTRANSFERASE AND CATECHOL-O-METHYLTRANSFERASE ACTIVITY IN RABBIT ADRENAL GLANDS DURING PREGNANCY

Glucocorticoid hypertension and nonadrenal phenylethanolamine N-methyltransferase.

Several drugs that block epinephrine synthesis by inhibiting phenylethanolamine N-methyltransferase (PNMT) lower blood pressure in hypertensive rats. We investigated the mechanism by which these drugs lower blood pressure in rats made hypertensive with the glucocorticoid dexamethasone. We performed adrenalectomy or sham operation on several rats and then gave them either dexamethasone chronical...

Central elevation of phenylethanolamine N-methyltransferase activity following stress.

Phenylethanolamine N-methyltransferase (PNMT, E.C.2.1.1.28) is the terminal enzyme in the synthesis of adrenaline ill the adrenal medulla 1, other chromaffin tissues, and in the mammalian brain iv. Changes in the level of adrenal and hypothalamic PNM T activity have been correlated with changes in the tissue content of adrenaline 13,15,1s,2°. It is well established that PNMT requires glucocorti...

Catechol-O-Methyltransferase in Parkinson’s Disease

The introduction of levodopa therapy for Parkinson’s disease (PD), initially by Birkmayer and colleagues in 1961 and Barbeau and colleagues in 1962, and in its ultimately successful form by Cotzias and colleagues in 1967, still represents the defining landmark in the treatment of PD (1–3). This dramatic advance was preceded by methodical basic laboratory research in the late 1950s and early 196...

Catechol-o-methyltransferase Activity: Assay, Distribution and Pharmacological Modification

Convergent Mechanistic Features between the Structurally Diverse N- and O-Methyltransferases: Glycine N-Methyltransferase and Catechol O-Methyltransferase

Although an enormous and still growing number of biologically diverse methyltransferases have been reported and identified, a comprehensive understanding of the enzymatic methyl transfer mechanism is still lacking. Glycine N-methyltransferase (GNMT), a member of the family that acts on small metabolites as the substrate, catalyzes methyl transfer from S-adenosyl-l-methionine (AdoMet) to glycine...