The effect of castration on steady state levels of luteinizing hormone-releasing hormone (LHRH) mRNA and proLHRH processing

Time course study utilizing semi-quantitative reverse transcription/polymerase chain reaction

N. V. Emanuele, J. Jurgens, N. La Paglia, D. W. Williams, Mark Kelley

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Many studies have consistently shown that castration induces a prompt increase in serum levels and pituitary content of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as a concomitant rise in steady state levels of the messenger RNAs directing their synthesis. The reports of effects of castration on the overall physiology of hypothalamic luteinizing hormone-releasing hormone (LHRH) - steady state levels of LHRH mRNA, post-translational processing and secretion - have, however, not been consistent. The goal of the studies reported here was to provide the first analysis of the effect of castration, at multiple postoperative time points, on steady state levels of LHRH mRNA and on the levels of hypothalamic proLHRH. All these data are correlated with hypothalamic levels of the mature LHRH decapeptide and with serum and pituitary levels of immunoreactive LH and FSH. Adult male rats were either castrated or sham-castrated (controls) and then sacrificed at 1, 3, 5, 7, 14, 21 or 28 days postoperatively. As expected, there was a prompt and sustained rise in serum immunoreactive LH and FSH in castrates compared with sham-operated animals. Intra-pituitary LH levels rose above levels in the sham-operated animals by 14 days post castration. Intra-pituitary FSH showed a biphasic response, first falling significantly below control levels, then rising above control levels at 21 days. Steady state levels of LHRH mRNA in castrates, measured by reverse transcription/polymerase chain reaction, were increased about 2-fold above control levels by 1 day postoperatively, but were virtually identical to control levels at each of the other time points despite marked changes in the gonadotropins. ProLHRH content in castrates was 1.8-times that seen in controls at 1 day post castration (P <0.05), concomitant with the rise in steady state levels of LHRH mRNA at that time point. However, proLHRH content in castrates was no different from that seen in controls at each of the later time points examined. LHRH content was unchanged through 7 days after castration, but then fell significantly to 57% of control levels in hypothalami from animals gonadectomized 14 to 21 days previously (P <0.001 vs control), and to 54% of sham-operated levels at 28 days postoperatively (P <0.001). We conclude that: (1) changes in steady state levels of LHRH mRNA after castration are small and transient and (2) increased proLHRH coupled with unchanged LHRH levels at 1 day post castration, and castrate animal proLHRH at control levels coupled with falling LHRH at later post-castration time points indicate that the effect of gonadectomy on post-translational processing of proLHRH to LHRH is, likewise, small and transient. In aggregate our data suggest that most of the increase in serum LH and FSH seen in male rats after castration is not mediated at the hypothalamic level.

Original languageEnglish (US)
Pages (from-to)509-515
Number of pages7
JournalJournal of Endocrinology
Volume148
Issue number3
StatePublished - 1996
Externally publishedYes

Fingerprint

Castration
Gonadotropin-Releasing Hormone
Reverse Transcription
Polymerase Chain Reaction
Messenger RNA
Follicle Stimulating Hormone
Luteinizing Hormone
Pituitary Hormones
Serum
Hypothalamic Hormones
Pituitary Gonadotropins
Gonadotropins
Hypothalamus

ASJC Scopus subject areas

  • Endocrinology

Cite this

@article{9c14e07251be4d1b959577133bc72769,
title = "The effect of castration on steady state levels of luteinizing hormone-releasing hormone (LHRH) mRNA and proLHRH processing: Time course study utilizing semi-quantitative reverse transcription/polymerase chain reaction",
abstract = "Many studies have consistently shown that castration induces a prompt increase in serum levels and pituitary content of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as a concomitant rise in steady state levels of the messenger RNAs directing their synthesis. The reports of effects of castration on the overall physiology of hypothalamic luteinizing hormone-releasing hormone (LHRH) - steady state levels of LHRH mRNA, post-translational processing and secretion - have, however, not been consistent. The goal of the studies reported here was to provide the first analysis of the effect of castration, at multiple postoperative time points, on steady state levels of LHRH mRNA and on the levels of hypothalamic proLHRH. All these data are correlated with hypothalamic levels of the mature LHRH decapeptide and with serum and pituitary levels of immunoreactive LH and FSH. Adult male rats were either castrated or sham-castrated (controls) and then sacrificed at 1, 3, 5, 7, 14, 21 or 28 days postoperatively. As expected, there was a prompt and sustained rise in serum immunoreactive LH and FSH in castrates compared with sham-operated animals. Intra-pituitary LH levels rose above levels in the sham-operated animals by 14 days post castration. Intra-pituitary FSH showed a biphasic response, first falling significantly below control levels, then rising above control levels at 21 days. Steady state levels of LHRH mRNA in castrates, measured by reverse transcription/polymerase chain reaction, were increased about 2-fold above control levels by 1 day postoperatively, but were virtually identical to control levels at each of the other time points despite marked changes in the gonadotropins. ProLHRH content in castrates was 1.8-times that seen in controls at 1 day post castration (P <0.05), concomitant with the rise in steady state levels of LHRH mRNA at that time point. However, proLHRH content in castrates was no different from that seen in controls at each of the later time points examined. LHRH content was unchanged through 7 days after castration, but then fell significantly to 57{\%} of control levels in hypothalami from animals gonadectomized 14 to 21 days previously (P <0.001 vs control), and to 54{\%} of sham-operated levels at 28 days postoperatively (P <0.001). We conclude that: (1) changes in steady state levels of LHRH mRNA after castration are small and transient and (2) increased proLHRH coupled with unchanged LHRH levels at 1 day post castration, and castrate animal proLHRH at control levels coupled with falling LHRH at later post-castration time points indicate that the effect of gonadectomy on post-translational processing of proLHRH to LHRH is, likewise, small and transient. In aggregate our data suggest that most of the increase in serum LH and FSH seen in male rats after castration is not mediated at the hypothalamic level.",
author = "Emanuele, {N. V.} and J. Jurgens and {La Paglia}, N. and Williams, {D. W.} and Mark Kelley",
year = "1996",
language = "English (US)",
volume = "148",
pages = "509--515",
journal = "Journal of Endocrinology",
issn = "0022-0795",
publisher = "Society for Endocrinology",
number = "3",

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TY - JOUR

T1 - The effect of castration on steady state levels of luteinizing hormone-releasing hormone (LHRH) mRNA and proLHRH processing

T2 - Time course study utilizing semi-quantitative reverse transcription/polymerase chain reaction

AU - Emanuele, N. V.

AU - Jurgens, J.

AU - La Paglia, N.

AU - Williams, D. W.

AU - Kelley, Mark

PY - 1996

Y1 - 1996

N2 - Many studies have consistently shown that castration induces a prompt increase in serum levels and pituitary content of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as a concomitant rise in steady state levels of the messenger RNAs directing their synthesis. The reports of effects of castration on the overall physiology of hypothalamic luteinizing hormone-releasing hormone (LHRH) - steady state levels of LHRH mRNA, post-translational processing and secretion - have, however, not been consistent. The goal of the studies reported here was to provide the first analysis of the effect of castration, at multiple postoperative time points, on steady state levels of LHRH mRNA and on the levels of hypothalamic proLHRH. All these data are correlated with hypothalamic levels of the mature LHRH decapeptide and with serum and pituitary levels of immunoreactive LH and FSH. Adult male rats were either castrated or sham-castrated (controls) and then sacrificed at 1, 3, 5, 7, 14, 21 or 28 days postoperatively. As expected, there was a prompt and sustained rise in serum immunoreactive LH and FSH in castrates compared with sham-operated animals. Intra-pituitary LH levels rose above levels in the sham-operated animals by 14 days post castration. Intra-pituitary FSH showed a biphasic response, first falling significantly below control levels, then rising above control levels at 21 days. Steady state levels of LHRH mRNA in castrates, measured by reverse transcription/polymerase chain reaction, were increased about 2-fold above control levels by 1 day postoperatively, but were virtually identical to control levels at each of the other time points despite marked changes in the gonadotropins. ProLHRH content in castrates was 1.8-times that seen in controls at 1 day post castration (P <0.05), concomitant with the rise in steady state levels of LHRH mRNA at that time point. However, proLHRH content in castrates was no different from that seen in controls at each of the later time points examined. LHRH content was unchanged through 7 days after castration, but then fell significantly to 57% of control levels in hypothalami from animals gonadectomized 14 to 21 days previously (P <0.001 vs control), and to 54% of sham-operated levels at 28 days postoperatively (P <0.001). We conclude that: (1) changes in steady state levels of LHRH mRNA after castration are small and transient and (2) increased proLHRH coupled with unchanged LHRH levels at 1 day post castration, and castrate animal proLHRH at control levels coupled with falling LHRH at later post-castration time points indicate that the effect of gonadectomy on post-translational processing of proLHRH to LHRH is, likewise, small and transient. In aggregate our data suggest that most of the increase in serum LH and FSH seen in male rats after castration is not mediated at the hypothalamic level.

AB - Many studies have consistently shown that castration induces a prompt increase in serum levels and pituitary content of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as a concomitant rise in steady state levels of the messenger RNAs directing their synthesis. The reports of effects of castration on the overall physiology of hypothalamic luteinizing hormone-releasing hormone (LHRH) - steady state levels of LHRH mRNA, post-translational processing and secretion - have, however, not been consistent. The goal of the studies reported here was to provide the first analysis of the effect of castration, at multiple postoperative time points, on steady state levels of LHRH mRNA and on the levels of hypothalamic proLHRH. All these data are correlated with hypothalamic levels of the mature LHRH decapeptide and with serum and pituitary levels of immunoreactive LH and FSH. Adult male rats were either castrated or sham-castrated (controls) and then sacrificed at 1, 3, 5, 7, 14, 21 or 28 days postoperatively. As expected, there was a prompt and sustained rise in serum immunoreactive LH and FSH in castrates compared with sham-operated animals. Intra-pituitary LH levels rose above levels in the sham-operated animals by 14 days post castration. Intra-pituitary FSH showed a biphasic response, first falling significantly below control levels, then rising above control levels at 21 days. Steady state levels of LHRH mRNA in castrates, measured by reverse transcription/polymerase chain reaction, were increased about 2-fold above control levels by 1 day postoperatively, but were virtually identical to control levels at each of the other time points despite marked changes in the gonadotropins. ProLHRH content in castrates was 1.8-times that seen in controls at 1 day post castration (P <0.05), concomitant with the rise in steady state levels of LHRH mRNA at that time point. However, proLHRH content in castrates was no different from that seen in controls at each of the later time points examined. LHRH content was unchanged through 7 days after castration, but then fell significantly to 57% of control levels in hypothalami from animals gonadectomized 14 to 21 days previously (P <0.001 vs control), and to 54% of sham-operated levels at 28 days postoperatively (P <0.001). We conclude that: (1) changes in steady state levels of LHRH mRNA after castration are small and transient and (2) increased proLHRH coupled with unchanged LHRH levels at 1 day post castration, and castrate animal proLHRH at control levels coupled with falling LHRH at later post-castration time points indicate that the effect of gonadectomy on post-translational processing of proLHRH to LHRH is, likewise, small and transient. In aggregate our data suggest that most of the increase in serum LH and FSH seen in male rats after castration is not mediated at the hypothalamic level.

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