Catechol estrogen formation by the CNS: Regional distribution of estrogen-2/4-hydroxylase activity in rat brain

J. Weisz; W. R. Crowley

doi:10.1159/000124580

Catechol estrogen formation by the CNS: Regional distribution of estrogen-2/4-hydroxylase activity in rat brain

J. Weisz, W. R. Crowley

Department of Obstetrics and Gynecology

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Abstract

Estrogen-2/4-hydroxylase (E-2/4-H) activity was measured by a direct product isolation assay in punch biopsy specimens obtained from nine nuclear regions from forebrain of adult male rats. Tritiated catechol estrogens were isolated from incubations of tissue with [6,7-³H]estradiol from all regions studied. The amount of 4-hydroxyestradiol (4-OH-E₂) formed equaled or exceeded that of 2-hydroxyestradiol (2-OH-E₂). There were significant regional differences in the amounts of catechol estrogen produced. The difference was nearly 8-fold between the arcuate-median eminence (ARC-ME) and the medial preoptic nucleus (POM), regions with the highest and lowest specific activities, respectively (37.7 ± 6.2 vs. 5.1 ± 0.7 pmol/mg protein/10 min 2-OH-E₂, mean + SEM, n = 6), The supraoptic nucleus was the site of second highest concentrations of E-2/4-H activity (20.3 pmol 2-OH-E₂/mg protein/10 min). Estrogen-2/4-H activity in the paraventricular (PVN) and periventricular (PERI) nuclear regions, though only about half that in the SON, was significantly greater than in the remaining brain areas (nucleus interstitialis striae terminalis, caudate, anterior hypothalamic and medial preoptic nuclei and cortex. The ARC-ME, the region with the highest E-2/4-H activity is where the dopaminergic neurones and terminals from the Gn-RH neurons are concentrated. The functions regulated by these two classes of neurones, the secretion of prolactin and gonadotrophins, respectively, have been the subject of most of the previous studies aimed at establishing the role of catechol estrogen formation in the hypothalamus. The SON and PVN, additional sites with high E-2/4-H activity, are the regions where the magnocellular, oxytocinergic and vasopressinergic neurones are concentrated. These neurones, though recognized targets of estrogens' action, have not been considered previously potential sites of catechol estrogen formation or as targets of their actions.

Original language	English (US)
Pages (from-to)	543-549
Number of pages	7
Journal	Neuroendocrinology
Volume	43
Issue number	5
DOIs	https://doi.org/10.1159/000124580
State	Published - 1986

All Science Journal Classification (ASJC) codes

Endocrinology, Diabetes and Metabolism
Endocrinology
Endocrine and Autonomic Systems
Cellular and Molecular Neuroscience

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10.1159/000124580

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@article{2e11b5118c844853b3f7a96f7c08f0cb,

title = "Catechol estrogen formation by the CNS: Regional distribution of estrogen-2/4-hydroxylase activity in rat brain",

abstract = "Estrogen-2/4-hydroxylase (E-2/4-H) activity was measured by a direct product isolation assay in punch biopsy specimens obtained from nine nuclear regions from forebrain of adult male rats. Tritiated catechol estrogens were isolated from incubations of tissue with [6,7-3H]estradiol from all regions studied. The amount of 4-hydroxyestradiol (4-OH-E2) formed equaled or exceeded that of 2-hydroxyestradiol (2-OH-E2). There were significant regional differences in the amounts of catechol estrogen produced. The difference was nearly 8-fold between the arcuate-median eminence (ARC-ME) and the medial preoptic nucleus (POM), regions with the highest and lowest specific activities, respectively (37.7 ± 6.2 vs. 5.1 ± 0.7 pmol/mg protein/10 min 2-OH-E2, mean + SEM, n = 6), The supraoptic nucleus was the site of second highest concentrations of E-2/4-H activity (20.3 pmol 2-OH-E2/mg protein/10 min). Estrogen-2/4-H activity in the paraventricular (PVN) and periventricular (PERI) nuclear regions, though only about half that in the SON, was significantly greater than in the remaining brain areas (nucleus interstitialis striae terminalis, caudate, anterior hypothalamic and medial preoptic nuclei and cortex. The ARC-ME, the region with the highest E-2/4-H activity is where the dopaminergic neurones and terminals from the Gn-RH neurons are concentrated. The functions regulated by these two classes of neurones, the secretion of prolactin and gonadotrophins, respectively, have been the subject of most of the previous studies aimed at establishing the role of catechol estrogen formation in the hypothalamus. The SON and PVN, additional sites with high E-2/4-H activity, are the regions where the magnocellular, oxytocinergic and vasopressinergic neurones are concentrated. These neurones, though recognized targets of estrogens' action, have not been considered previously potential sites of catechol estrogen formation or as targets of their actions.",

author = "J. Weisz and Crowley, {W. R.}",

year = "1986",

doi = "10.1159/000124580",

language = "English (US)",

volume = "43",

pages = "543--549",

journal = "Neuroendocrinology",

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TY - JOUR

T1 - Catechol estrogen formation by the CNS

T2 - Regional distribution of estrogen-2/4-hydroxylase activity in rat brain

AU - Weisz, J.

AU - Crowley, W. R.

PY - 1986

Y1 - 1986

N2 - Estrogen-2/4-hydroxylase (E-2/4-H) activity was measured by a direct product isolation assay in punch biopsy specimens obtained from nine nuclear regions from forebrain of adult male rats. Tritiated catechol estrogens were isolated from incubations of tissue with [6,7-3H]estradiol from all regions studied. The amount of 4-hydroxyestradiol (4-OH-E2) formed equaled or exceeded that of 2-hydroxyestradiol (2-OH-E2). There were significant regional differences in the amounts of catechol estrogen produced. The difference was nearly 8-fold between the arcuate-median eminence (ARC-ME) and the medial preoptic nucleus (POM), regions with the highest and lowest specific activities, respectively (37.7 ± 6.2 vs. 5.1 ± 0.7 pmol/mg protein/10 min 2-OH-E2, mean + SEM, n = 6), The supraoptic nucleus was the site of second highest concentrations of E-2/4-H activity (20.3 pmol 2-OH-E2/mg protein/10 min). Estrogen-2/4-H activity in the paraventricular (PVN) and periventricular (PERI) nuclear regions, though only about half that in the SON, was significantly greater than in the remaining brain areas (nucleus interstitialis striae terminalis, caudate, anterior hypothalamic and medial preoptic nuclei and cortex. The ARC-ME, the region with the highest E-2/4-H activity is where the dopaminergic neurones and terminals from the Gn-RH neurons are concentrated. The functions regulated by these two classes of neurones, the secretion of prolactin and gonadotrophins, respectively, have been the subject of most of the previous studies aimed at establishing the role of catechol estrogen formation in the hypothalamus. The SON and PVN, additional sites with high E-2/4-H activity, are the regions where the magnocellular, oxytocinergic and vasopressinergic neurones are concentrated. These neurones, though recognized targets of estrogens' action, have not been considered previously potential sites of catechol estrogen formation or as targets of their actions.

AB - Estrogen-2/4-hydroxylase (E-2/4-H) activity was measured by a direct product isolation assay in punch biopsy specimens obtained from nine nuclear regions from forebrain of adult male rats. Tritiated catechol estrogens were isolated from incubations of tissue with [6,7-3H]estradiol from all regions studied. The amount of 4-hydroxyestradiol (4-OH-E2) formed equaled or exceeded that of 2-hydroxyestradiol (2-OH-E2). There were significant regional differences in the amounts of catechol estrogen produced. The difference was nearly 8-fold between the arcuate-median eminence (ARC-ME) and the medial preoptic nucleus (POM), regions with the highest and lowest specific activities, respectively (37.7 ± 6.2 vs. 5.1 ± 0.7 pmol/mg protein/10 min 2-OH-E2, mean + SEM, n = 6), The supraoptic nucleus was the site of second highest concentrations of E-2/4-H activity (20.3 pmol 2-OH-E2/mg protein/10 min). Estrogen-2/4-H activity in the paraventricular (PVN) and periventricular (PERI) nuclear regions, though only about half that in the SON, was significantly greater than in the remaining brain areas (nucleus interstitialis striae terminalis, caudate, anterior hypothalamic and medial preoptic nuclei and cortex. The ARC-ME, the region with the highest E-2/4-H activity is where the dopaminergic neurones and terminals from the Gn-RH neurons are concentrated. The functions regulated by these two classes of neurones, the secretion of prolactin and gonadotrophins, respectively, have been the subject of most of the previous studies aimed at establishing the role of catechol estrogen formation in the hypothalamus. The SON and PVN, additional sites with high E-2/4-H activity, are the regions where the magnocellular, oxytocinergic and vasopressinergic neurones are concentrated. These neurones, though recognized targets of estrogens' action, have not been considered previously potential sites of catechol estrogen formation or as targets of their actions.

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Catechol estrogen formation by the CNS: Regional distribution of estrogen-2/4-hydroxylase activity in rat brain

Abstract

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