Regulation of hypothalamic gonadotropin-releasing hormone and neuropeptide y concentrations by progesterone and corticosteroids in immature rats: Correlation with luteinizing hormone and follicle-stimulating hormone release

Darrell W. Brann, John K. McDonald, C. D. Putnam, Virendra B. Mahesh

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Abstract

In a previous study, we demonstrated that progesterone (P4) and the synthetic glucocorticoid triamcinolone acetonide (TA), but not cortisol, could induce LH and FSH release in estrogen-primed ovariectomized immature rats. Therefore, the purpose of this study was to determine if the stimulatory effect of P4 and TA on LH and FSH release were associated with changes in GnRH or NPY concentrations in the medial basal hypothalamus (MBH) or preoptic area (POA). Ovariectomized immature rats primed with estradiol at 27 and 28 days received either vehicle, P4, TA or cortisol (1 mg/kg BW) at 9.00 h on day 29. Animals were killed at 9.30, 10.00, 12.00 and 13.00 h on day 29 for serum LH and FSH measurements, and the MBH and POA were dissected and analyzed for GnRH and NPY concentrations via RIAs. P4- and TA-treated animals showed significantly elevated serum LH and FSH levels from 13.00 h to 15.00 h. Cortisol was without effect. P4 significantly increased MBH GnRH and NPY concentrations at 12.00 h followed by a significant fall at 13.00 h. P4 modulated POA GnRH and NPY concentrations in a fashion similar to that seen in the MBH, except POA NPY concentrations did not fall at 13.00 h after the elevation at 12.00 h. TA had no significant effect on MBH GnRH and NPY levels at 12.00 h compared to the values at 9.30 h and 10.00 h but, as with P4, there was a significant fall in MBH GnRH and NPY levels at 13.00 h. TA had no significant effect on POA GnRH and NPY concentrations at any time point studied. Consistent with its lack of effect on serum LH and FSH, cortisol had no effect on MBH GnRH and NPY. Interestingly, cortisol significantly increased POA LHRH and NPYat 12.00 h followed by a fall at 13.00 h. However, cortisol had no effect on LH and FSH levels on the day of administration. In summary, the stimulatory effects of P4 and TA on LH and FSH release in the estrogen-primed ovariectomized immature rat appear to be mediated by a similar mechanism involving changes in MBH and POA GnRH and NPY concentrations.

Original languageEnglish (US)
Pages (from-to)425-432
Number of pages8
JournalNeuroendocrinology
Volume54
Issue number5
DOIs
StatePublished - Jan 1 1991

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Pituitary Hormone-Releasing Hormones
Middle Hypothalamus
Follicle Stimulating Hormone
Luteinizing Hormone
Neuropeptides
Gonadotropin-Releasing Hormone
Triamcinolone Acetonide
Progesterone
Preoptic Area
Adrenal Cortex Hormones
Hydrocortisone
Estrogens
Serum
Glucocorticoids
Estradiol

Keywords

  • Corticosteroid
  • Follicle-stimulating hormone
  • Gonadotropin
  • Gonadotropin-releasing hormone
  • Luteinizing hormone
  • Neuropeptide Y
  • Progesterone

ASJC Scopus subject areas

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

Cite this

@article{81d1236df65a4a65a11c52c01cd32b5d,
title = "Regulation of hypothalamic gonadotropin-releasing hormone and neuropeptide y concentrations by progesterone and corticosteroids in immature rats: Correlation with luteinizing hormone and follicle-stimulating hormone release",
abstract = "In a previous study, we demonstrated that progesterone (P4) and the synthetic glucocorticoid triamcinolone acetonide (TA), but not cortisol, could induce LH and FSH release in estrogen-primed ovariectomized immature rats. Therefore, the purpose of this study was to determine if the stimulatory effect of P4 and TA on LH and FSH release were associated with changes in GnRH or NPY concentrations in the medial basal hypothalamus (MBH) or preoptic area (POA). Ovariectomized immature rats primed with estradiol at 27 and 28 days received either vehicle, P4, TA or cortisol (1 mg/kg BW) at 9.00 h on day 29. Animals were killed at 9.30, 10.00, 12.00 and 13.00 h on day 29 for serum LH and FSH measurements, and the MBH and POA were dissected and analyzed for GnRH and NPY concentrations via RIAs. P4- and TA-treated animals showed significantly elevated serum LH and FSH levels from 13.00 h to 15.00 h. Cortisol was without effect. P4 significantly increased MBH GnRH and NPY concentrations at 12.00 h followed by a significant fall at 13.00 h. P4 modulated POA GnRH and NPY concentrations in a fashion similar to that seen in the MBH, except POA NPY concentrations did not fall at 13.00 h after the elevation at 12.00 h. TA had no significant effect on MBH GnRH and NPY levels at 12.00 h compared to the values at 9.30 h and 10.00 h but, as with P4, there was a significant fall in MBH GnRH and NPY levels at 13.00 h. TA had no significant effect on POA GnRH and NPY concentrations at any time point studied. Consistent with its lack of effect on serum LH and FSH, cortisol had no effect on MBH GnRH and NPY. Interestingly, cortisol significantly increased POA LHRH and NPYat 12.00 h followed by a fall at 13.00 h. However, cortisol had no effect on LH and FSH levels on the day of administration. In summary, the stimulatory effects of P4 and TA on LH and FSH release in the estrogen-primed ovariectomized immature rat appear to be mediated by a similar mechanism involving changes in MBH and POA GnRH and NPY concentrations.",
keywords = "Corticosteroid, Follicle-stimulating hormone, Gonadotropin, Gonadotropin-releasing hormone, Luteinizing hormone, Neuropeptide Y, Progesterone",
author = "Brann, {Darrell W.} and McDonald, {John K.} and Putnam, {C. D.} and Mahesh, {Virendra B.}",
year = "1991",
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day = "1",
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language = "English (US)",
volume = "54",
pages = "425--432",
journal = "Neuroendocrinology",
issn = "0028-3835",
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TY - JOUR

T1 - Regulation of hypothalamic gonadotropin-releasing hormone and neuropeptide y concentrations by progesterone and corticosteroids in immature rats

T2 - Correlation with luteinizing hormone and follicle-stimulating hormone release

AU - Brann, Darrell W.

AU - McDonald, John K.

AU - Putnam, C. D.

AU - Mahesh, Virendra B.

PY - 1991/1/1

Y1 - 1991/1/1

N2 - In a previous study, we demonstrated that progesterone (P4) and the synthetic glucocorticoid triamcinolone acetonide (TA), but not cortisol, could induce LH and FSH release in estrogen-primed ovariectomized immature rats. Therefore, the purpose of this study was to determine if the stimulatory effect of P4 and TA on LH and FSH release were associated with changes in GnRH or NPY concentrations in the medial basal hypothalamus (MBH) or preoptic area (POA). Ovariectomized immature rats primed with estradiol at 27 and 28 days received either vehicle, P4, TA or cortisol (1 mg/kg BW) at 9.00 h on day 29. Animals were killed at 9.30, 10.00, 12.00 and 13.00 h on day 29 for serum LH and FSH measurements, and the MBH and POA were dissected and analyzed for GnRH and NPY concentrations via RIAs. P4- and TA-treated animals showed significantly elevated serum LH and FSH levels from 13.00 h to 15.00 h. Cortisol was without effect. P4 significantly increased MBH GnRH and NPY concentrations at 12.00 h followed by a significant fall at 13.00 h. P4 modulated POA GnRH and NPY concentrations in a fashion similar to that seen in the MBH, except POA NPY concentrations did not fall at 13.00 h after the elevation at 12.00 h. TA had no significant effect on MBH GnRH and NPY levels at 12.00 h compared to the values at 9.30 h and 10.00 h but, as with P4, there was a significant fall in MBH GnRH and NPY levels at 13.00 h. TA had no significant effect on POA GnRH and NPY concentrations at any time point studied. Consistent with its lack of effect on serum LH and FSH, cortisol had no effect on MBH GnRH and NPY. Interestingly, cortisol significantly increased POA LHRH and NPYat 12.00 h followed by a fall at 13.00 h. However, cortisol had no effect on LH and FSH levels on the day of administration. In summary, the stimulatory effects of P4 and TA on LH and FSH release in the estrogen-primed ovariectomized immature rat appear to be mediated by a similar mechanism involving changes in MBH and POA GnRH and NPY concentrations.

AB - In a previous study, we demonstrated that progesterone (P4) and the synthetic glucocorticoid triamcinolone acetonide (TA), but not cortisol, could induce LH and FSH release in estrogen-primed ovariectomized immature rats. Therefore, the purpose of this study was to determine if the stimulatory effect of P4 and TA on LH and FSH release were associated with changes in GnRH or NPY concentrations in the medial basal hypothalamus (MBH) or preoptic area (POA). Ovariectomized immature rats primed with estradiol at 27 and 28 days received either vehicle, P4, TA or cortisol (1 mg/kg BW) at 9.00 h on day 29. Animals were killed at 9.30, 10.00, 12.00 and 13.00 h on day 29 for serum LH and FSH measurements, and the MBH and POA were dissected and analyzed for GnRH and NPY concentrations via RIAs. P4- and TA-treated animals showed significantly elevated serum LH and FSH levels from 13.00 h to 15.00 h. Cortisol was without effect. P4 significantly increased MBH GnRH and NPY concentrations at 12.00 h followed by a significant fall at 13.00 h. P4 modulated POA GnRH and NPY concentrations in a fashion similar to that seen in the MBH, except POA NPY concentrations did not fall at 13.00 h after the elevation at 12.00 h. TA had no significant effect on MBH GnRH and NPY levels at 12.00 h compared to the values at 9.30 h and 10.00 h but, as with P4, there was a significant fall in MBH GnRH and NPY levels at 13.00 h. TA had no significant effect on POA GnRH and NPY concentrations at any time point studied. Consistent with its lack of effect on serum LH and FSH, cortisol had no effect on MBH GnRH and NPY. Interestingly, cortisol significantly increased POA LHRH and NPYat 12.00 h followed by a fall at 13.00 h. However, cortisol had no effect on LH and FSH levels on the day of administration. In summary, the stimulatory effects of P4 and TA on LH and FSH release in the estrogen-primed ovariectomized immature rat appear to be mediated by a similar mechanism involving changes in MBH and POA GnRH and NPY concentrations.

KW - Corticosteroid

KW - Follicle-stimulating hormone

KW - Gonadotropin

KW - Gonadotropin-releasing hormone

KW - Luteinizing hormone

KW - Neuropeptide Y

KW - Progesterone

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U2 - 10.1159/000125930

DO - 10.1159/000125930

M3 - Article

C2 - 1749457

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VL - 54

SP - 425

EP - 432

JO - Neuroendocrinology

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SN - 0028-3835

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