Phenol sulfotransferase, or PST (EC 2.8.2.1 ), catalyzes the sulfate conjugation of catecholamines and of phenolic
drugs. PST is widely distributed in human and animal tissues that include the blood platelets.
NCBI Summary:
Sulfotransferase enzymes catalyze the sulfate conjugation of many hormones, neurotransmitters, drugs, and xenobiotic compounds. These cytosolic enzymes are different in their tissue distributions and substrate specificities. The gene structure (number and length of exons) is similar among family members. This gene encodes one of two phenol sulfotransferases with thermostable enzyme activity. Multiple alternatively spliced variants that encode two isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]
General function
Metabolism, Enzyme, Transferase
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Comment
Bostrom M, et al reported the conjugation of 1-naphthol in primary cell cultures of rat
ovarian cells.
Two phase II enzymes catalyzing conjugation, i.e. phenol sulfotransferase (P-SULT) and phenol UDP-glucuronosyltransferase (P-UGT), were
measured using I-naphthol as substrate. After 20 h of incubation the rate of conjugation in cells isolated from ovaries enriched in corpora lutea (CL)
exceeded the rate in cells isolated from ovaries enriched in preovulatory follicles. In addition, when the granulosa cells were removed from the preovulatory follicles, the rate of conjugation was 1.7-fold higher, i.e. in
the theca/stroma cells. When the cells were incubated with 1-[C-14]naphthol
and conjugates were subsequently separated by thin-layer chromatography,
naphthyl glucuronide was the only conjugate observed. Pentachlorophenol (PCP),
a commonly used inhibitor of P-SULT, inhibited 1-naphthol conjugation 50% in
cell cultures, as well as in microsomal preparations, alpha-Naphthoflavone
(ANF) and ellipticine (ELP), both cytochrome P450 (CYP) inhibitors, affected
the conjugation of 1-naphthol in different ways; ANF did not affect P-UGT
activity in microsomal preparations, but inhibited 1-naphthol conjugation in
cell cultures by as much as 90%. On the other hand, ELF inhibited the
conjugation of 1-naphthol up to 99% in the cell cultures, but only 75% in
microsomal fractions. Testosterone (TST) and estradiol inhibited this activity
approximate to 50% in both of these experimental systems. The present findings demonstrate that
P-UGT is by far the major enzyme conjugating 1-naphthol in the rat ovary and that commonly used inhibitors of P-SULT and CYPs also inhibit P-UGT activity,
either directly or via other mechanisms.
Expression regulated by
Comment
Ovarian localization
Granulosa, Theca
Comment
Action of Halowax 1051 on Enzymes of Phase I (CYP1A1) and Phase II (SULT1A and COMT) Metabolism in the Pig Ovary. Barc J et al. Polychlorinated naphthalenes (PCNs) are a group of organochlorinated compounds exhibiting dioxin-like properties. Previously published data showed the direct action of PCN-rich Halowax 1051 on ovarian follicular steroidogenesis. Taking into consideration that the observed biological effects of PCNs may be frequently side effects of metabolites generated by their detoxification, the aim of this study was to determine the activity and expression of enzymes involved in phase I (cytochrome P450, family 1 (CYP1A1)) and phase II (sulfotransferase (SULT1A) and catechol-O-methyltransferase (COMT)) detoxification metabolism. Cocultures of granulosa and theca interna cells collected from sexually mature pigs were exposed to 1?pg/mL to 10?ng/mL of Halowax 1051 for 1 to 48 hours, after which levels and activities of CYP1A1, SULT1A, and COMT were measured. Dose-dependent increases of CYP1A1 activity and expression were observed. High doses of Halowax 1051 were inhibitory to COMT and SULT1A activity and reduced their protein levels. In conclusion, fast activation of phase I enzymes with simultaneous inhibition of phase II enzymes indicates that the previously observed effect of Halowax 1051 on follicular steroidogenesis may partially result from metabolite action occurring locally in ovarian follicles.