Occurrence and Localization of Brain Phenolsulphotransferase

Abstract

—Rat brain contains the enzyme which forms sulphate conjugates of phenols, phenolsulphotransferase (EC 2.8.2.1), but the physiological role of the enzyme is unclear. The enzyme is unevenly distributed in rat brain, with the activity 13 times higher in the hypothalamus than in the cerebellum. Phenolsulphotransferase does not seem to be primarily located in glial cells. Cultured cells (type C6 astrocytoma) derived from rat glia had less than 1 per cent of the phenolsulphotransferase activity of whole rat brain. Sulphate conjugation of neutral compounds may be important in their removal from brain. The pineal and pituitary glands, areas outside the blood‐brain barrier had very low phenolsulphotransferase activity. The activity of the enzyme in brain varied widely among different species: rabbit and rat had much higher levels of activity than mouse or frog; the activity in human brain was intermediate. Phenolsulphotransferase also occurred in other organs, including liver, heart, testes, lung, spleen, salivary glands, and intact or decentralized superior cervical ganglion. There was no correlation of enzyme activity with adrenergic or cholinergic innervation, or with the known roles of various tissues in drug metabolism or detoxification. The enzyme activity does not seem to be under neuronal control since ganglionectomy did not affect the phenolsulphotransferase activity of salivary glands. The precise localization of phenolsulphotransferase remains to be established, as well as the physiological importance of sulphate conjugation of phenols in brain and other organs.

Modification of dopamine and norepinephrine metabolism in the rat brain by monoamine oxidase inhibitors

“…For example, it has been well documented that increase of DA in the brain tissues which follows injection of L-dopa did not lead to any change in NE concentrations (Freed and Murphy, 1978;Doshi and Edwards, 1981;Edwards and Rizk, 1982;Commissiong, 1984;Buu et al, 1985). Similar paradoxical observations extended to the lack ofDA sulfoconjugation by phenolsulfotransferase (PST) (Foldes and Meek, 1974;Buu et al, 1985) and O-methylation by catechol-Omethyltransferase (COMT) of the expanded DA pool.…”

Effects of Neonatal Handling on Central Noradrenergic and Nitric Oxidergic Systems and Reproductive Parameters in Female Rats

“…In the remaining pellet, protein content was determined by the Bradford method [46]. In the rat, MHPG is conjugated to MHPG-sulfate by phenolsulfotransferase [47]. Since MHPG-sulfate is not electrochemically active, free MHPG was deconjugated by heating for 5 min at 94°C before performing sample analysis by HPLC-ED, as previously described [48].…”

Urinary MHPG sulfate as a marker of central norepinephrine metabolism: a commentary

“…serotonin) whereas the P-type (TS) acts predominantly on non-amine phenol compounds. However, MHPG is sulfoconjugated by both enzymes (Foldes and Meek, 1974;Rein et al, 1984;Yu et al, 1985).…”