Effects of gonadectomy and hormone replacement on steroid hormone receptors and 5α-reductase activity in pituitaries of male rhesus macaques

Robert J Handa, J. A. Resko

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Abstract

We measured androgen, estrogen, and progestin receptors and 5α-reductase activity in the anterior and posterior pituitary gland of intact and 6-week castrate adult male rhesus monkeys and castrate males which were treated with testosterone (T) or estradiol (E) from time of surgery. Saturation analysis of anterior pituitary tissues from monkeys receiving various treatments revealed an apparent mean dissociation constant (K(d)) of 0.53 ± 0.17 (±SE) x 10-10 mol/L (n = 3) for [3H]R1881 (androgen) binding to cytosol, 2.6 ± 0.50 x 10-10 mol/L (n = 3) for [3H]R2858 (estrogen) binding to cytosol, 1.7 x 10-10 mol/L (n = 2) for [3H]R5020 (progestin) binding to cytosol, and 6.2 x 10-10 mol/L (n = 2) for [3H]R1881 binding to cell nuclear extract. The highest levels of nuclear androgen receptor (AR) were found in intact males [37.1 ± 3.5 (±SE) fmol/mg DNA; n = 7] and castrated males treated with T for 6 weeks (89.7 ± 30.2 fmol/mg DNA; n = 5). High levels of nuclear AR corresponded to serum T levels and low serum LH levels. Nuclear AR was undetectable in castrated males and castrated males treated with E. Significantly greater levels of cytosolic AR were detected in intact males (27.5 ± 1.6 fmol/mg protein) compared to all other groups (P < 0.05). T or E treatment had no effect on cytosolic AR. Increased levels of cytosolic progestin receptor were found in intact monkeys and after E or T treatment compared to levels in untreated castrates. No differences in 5α-reductase activity were found between any treatment groups. These data indicate that anterior pituitary nuclear androgen receptor is correlated with serum LH levels and support the hypothesis of a direct action of T on anterior pituitary LH secretion. In addition, it appears that cytosolic progestin receptor, but not AR, is regulated by estrogen in intact male rhesus monkeys. In the posterior pituitary, AR dynamics followed a profile in which cytosolic AR increased after castration and decreased after T treatment. The presence of a dynamic AR system in the posterior pituitary suggests hormonal regulation of its function by androgens.

Original languageEnglish (US)
Pages (from-to)1251-1258
Number of pages8
JournalJournal of Clinical Endocrinology and Metabolism
Volume66
Issue number6
StatePublished - 1988
Externally publishedYes

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Steroid hormones
Steroid Receptors
Androgen Receptors
Macaca mulatta
Oxidoreductases
Hormones
Cytoplasmic and Nuclear Receptors
Progesterone Receptors
Metribolone
Cytosol
moxestrol
Androgens
Haplorhini
Estrogens
Serum
Promegestone
Posterior Pituitary Gland
Anterior Pituitary Gland
Castration
DNA

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

Cite this

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title = "Effects of gonadectomy and hormone replacement on steroid hormone receptors and 5α-reductase activity in pituitaries of male rhesus macaques",
abstract = "We measured androgen, estrogen, and progestin receptors and 5α-reductase activity in the anterior and posterior pituitary gland of intact and 6-week castrate adult male rhesus monkeys and castrate males which were treated with testosterone (T) or estradiol (E) from time of surgery. Saturation analysis of anterior pituitary tissues from monkeys receiving various treatments revealed an apparent mean dissociation constant (K(d)) of 0.53 ± 0.17 (±SE) x 10-10 mol/L (n = 3) for [3H]R1881 (androgen) binding to cytosol, 2.6 ± 0.50 x 10-10 mol/L (n = 3) for [3H]R2858 (estrogen) binding to cytosol, 1.7 x 10-10 mol/L (n = 2) for [3H]R5020 (progestin) binding to cytosol, and 6.2 x 10-10 mol/L (n = 2) for [3H]R1881 binding to cell nuclear extract. The highest levels of nuclear androgen receptor (AR) were found in intact males [37.1 ± 3.5 (±SE) fmol/mg DNA; n = 7] and castrated males treated with T for 6 weeks (89.7 ± 30.2 fmol/mg DNA; n = 5). High levels of nuclear AR corresponded to serum T levels and low serum LH levels. Nuclear AR was undetectable in castrated males and castrated males treated with E. Significantly greater levels of cytosolic AR were detected in intact males (27.5 ± 1.6 fmol/mg protein) compared to all other groups (P < 0.05). T or E treatment had no effect on cytosolic AR. Increased levels of cytosolic progestin receptor were found in intact monkeys and after E or T treatment compared to levels in untreated castrates. No differences in 5α-reductase activity were found between any treatment groups. These data indicate that anterior pituitary nuclear androgen receptor is correlated with serum LH levels and support the hypothesis of a direct action of T on anterior pituitary LH secretion. In addition, it appears that cytosolic progestin receptor, but not AR, is regulated by estrogen in intact male rhesus monkeys. In the posterior pituitary, AR dynamics followed a profile in which cytosolic AR increased after castration and decreased after T treatment. The presence of a dynamic AR system in the posterior pituitary suggests hormonal regulation of its function by androgens.",
author = "Handa, {Robert J} and Resko, {J. A.}",
year = "1988",
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T1 - Effects of gonadectomy and hormone replacement on steroid hormone receptors and 5α-reductase activity in pituitaries of male rhesus macaques

AU - Handa, Robert J

AU - Resko, J. A.

PY - 1988

Y1 - 1988

N2 - We measured androgen, estrogen, and progestin receptors and 5α-reductase activity in the anterior and posterior pituitary gland of intact and 6-week castrate adult male rhesus monkeys and castrate males which were treated with testosterone (T) or estradiol (E) from time of surgery. Saturation analysis of anterior pituitary tissues from monkeys receiving various treatments revealed an apparent mean dissociation constant (K(d)) of 0.53 ± 0.17 (±SE) x 10-10 mol/L (n = 3) for [3H]R1881 (androgen) binding to cytosol, 2.6 ± 0.50 x 10-10 mol/L (n = 3) for [3H]R2858 (estrogen) binding to cytosol, 1.7 x 10-10 mol/L (n = 2) for [3H]R5020 (progestin) binding to cytosol, and 6.2 x 10-10 mol/L (n = 2) for [3H]R1881 binding to cell nuclear extract. The highest levels of nuclear androgen receptor (AR) were found in intact males [37.1 ± 3.5 (±SE) fmol/mg DNA; n = 7] and castrated males treated with T for 6 weeks (89.7 ± 30.2 fmol/mg DNA; n = 5). High levels of nuclear AR corresponded to serum T levels and low serum LH levels. Nuclear AR was undetectable in castrated males and castrated males treated with E. Significantly greater levels of cytosolic AR were detected in intact males (27.5 ± 1.6 fmol/mg protein) compared to all other groups (P < 0.05). T or E treatment had no effect on cytosolic AR. Increased levels of cytosolic progestin receptor were found in intact monkeys and after E or T treatment compared to levels in untreated castrates. No differences in 5α-reductase activity were found between any treatment groups. These data indicate that anterior pituitary nuclear androgen receptor is correlated with serum LH levels and support the hypothesis of a direct action of T on anterior pituitary LH secretion. In addition, it appears that cytosolic progestin receptor, but not AR, is regulated by estrogen in intact male rhesus monkeys. In the posterior pituitary, AR dynamics followed a profile in which cytosolic AR increased after castration and decreased after T treatment. The presence of a dynamic AR system in the posterior pituitary suggests hormonal regulation of its function by androgens.

AB - We measured androgen, estrogen, and progestin receptors and 5α-reductase activity in the anterior and posterior pituitary gland of intact and 6-week castrate adult male rhesus monkeys and castrate males which were treated with testosterone (T) or estradiol (E) from time of surgery. Saturation analysis of anterior pituitary tissues from monkeys receiving various treatments revealed an apparent mean dissociation constant (K(d)) of 0.53 ± 0.17 (±SE) x 10-10 mol/L (n = 3) for [3H]R1881 (androgen) binding to cytosol, 2.6 ± 0.50 x 10-10 mol/L (n = 3) for [3H]R2858 (estrogen) binding to cytosol, 1.7 x 10-10 mol/L (n = 2) for [3H]R5020 (progestin) binding to cytosol, and 6.2 x 10-10 mol/L (n = 2) for [3H]R1881 binding to cell nuclear extract. The highest levels of nuclear androgen receptor (AR) were found in intact males [37.1 ± 3.5 (±SE) fmol/mg DNA; n = 7] and castrated males treated with T for 6 weeks (89.7 ± 30.2 fmol/mg DNA; n = 5). High levels of nuclear AR corresponded to serum T levels and low serum LH levels. Nuclear AR was undetectable in castrated males and castrated males treated with E. Significantly greater levels of cytosolic AR were detected in intact males (27.5 ± 1.6 fmol/mg protein) compared to all other groups (P < 0.05). T or E treatment had no effect on cytosolic AR. Increased levels of cytosolic progestin receptor were found in intact monkeys and after E or T treatment compared to levels in untreated castrates. No differences in 5α-reductase activity were found between any treatment groups. These data indicate that anterior pituitary nuclear androgen receptor is correlated with serum LH levels and support the hypothesis of a direct action of T on anterior pituitary LH secretion. In addition, it appears that cytosolic progestin receptor, but not AR, is regulated by estrogen in intact male rhesus monkeys. In the posterior pituitary, AR dynamics followed a profile in which cytosolic AR increased after castration and decreased after T treatment. The presence of a dynamic AR system in the posterior pituitary suggests hormonal regulation of its function by androgens.

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