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Testosterone differentially modulates gonadotropin subunit messenger ribonucleic acid responses to gonadotropin-releasing hormone pulse amplitude.
Endocrinology. 1990 Dec; 127(6):2876-83.E

Abstract

Testosterone (T) inhibits GnRH secretion and can also modulate the effects of GnRH on gonadotropin synthesis and secretion. To assess the effect of T on GnRH stimulation of alpha, LH beta, and FSH beta mRNA expression, we replaced T at three levels to reproduce low (1.5 +/- 0.5 ng/ml), medium (3.5 +/- 0.3 ng/ml), and high (6.2 +/- 0.6 ng/ml) physiological plasma concentrations. Additionally, as peripheral conversion to dihydrotestosterone (DHT) or estradiol (E2) may mediate T action, the effects of GnRH pulses in the presence of DHT and E2 were also studied. Male rats were castrated, and steroids were replaced via implants containing either T (three doses) or DHT or E2 (two doses each). GnRH pulses (10-250 ng/pulse) were administered iv at 30-min intervals for 48 h. Pituitary subunit mRNA concentrations, gonadotropin content, and LH and FSH secretion were determined. The patterns of alpha, LH beta, and FSH beta mRNA responses to increasing GnRH pulse amplitude were similar at all concentrations of plasma T. Alpha mRNA concentrations were increased 2- to 4-fold by GnRH pulses. At the same plasma T concentration, all doses of GnRH produced similar increases in alpha mRNA, but the response tended to be lower at the higher (6.2 ng/ml) levels of T. LH beta mRNA showed a clear dependence on GnRH pulse amplitude, with the maximum responses (2- to 3-fold) occurring after 10- to 25-ng GnRH pulses. At the higher (3.5 and 6.2 ng/ml) T concentrations, the dose-response curve was shifted to the left. The lowest GnRH pulse dose (10 ng) produced maximum responses, and LH beta mRNA increments in response to the higher GnRH doses were suppressed. FSH beta mRNA concentrations were increased by T in saline-pulsed controls. FSH beta mRNA responses were similar (2- to 3-fold) after all GnRH doses and at all concentrations of T. Increasing GnRH pulse doses reduced the pituitary content of both LH and FSH at all levels of T. Acute LH secretion was maximal after 10- and 25-ng pulses of GnRH when plasma T was low, but increased progressively with GnRH dose at the highest plasma T concentrations. Plasma FSH did not show any differential responsiveness to GnRH pulse dose or to increasing plasma T. Thus, LH synthesis and secretion are affected more than those of FSH by changing plasma concentrations of T. T may modulate posttranslational events in LH secretion. The higher GnRH doses effected LH release without increasing LH beta mRNA in the presence of higher physiological concentrations of T.(

ABSTRACT

TRUNCATED AT 400 WORDS)

Authors+Show Affiliations

Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

1701131

Citation

Iliff-Sizemore, S A., et al. "Testosterone Differentially Modulates Gonadotropin Subunit Messenger Ribonucleic Acid Responses to Gonadotropin-releasing Hormone Pulse Amplitude." Endocrinology, vol. 127, no. 6, 1990, pp. 2876-83.
Iliff-Sizemore SA, Ortolano GA, Haisenleder DJ, et al. Testosterone differentially modulates gonadotropin subunit messenger ribonucleic acid responses to gonadotropin-releasing hormone pulse amplitude. Endocrinology. 1990;127(6):2876-83.
Iliff-Sizemore, S. A., Ortolano, G. A., Haisenleder, D. J., Dalkin, A. C., Krueger, K. A., & Marshall, J. C. (1990). Testosterone differentially modulates gonadotropin subunit messenger ribonucleic acid responses to gonadotropin-releasing hormone pulse amplitude. Endocrinology, 127(6), 2876-83.
Iliff-Sizemore SA, et al. Testosterone Differentially Modulates Gonadotropin Subunit Messenger Ribonucleic Acid Responses to Gonadotropin-releasing Hormone Pulse Amplitude. Endocrinology. 1990;127(6):2876-83. PubMed PMID: 1701131.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Testosterone differentially modulates gonadotropin subunit messenger ribonucleic acid responses to gonadotropin-releasing hormone pulse amplitude. AU - Iliff-Sizemore,S A, AU - Ortolano,G A, AU - Haisenleder,D J, AU - Dalkin,A C, AU - Krueger,K A, AU - Marshall,J C, PY - 1990/12/1/pubmed PY - 1990/12/1/medline PY - 1990/12/1/entrez SP - 2876 EP - 83 JF - Endocrinology JO - Endocrinology VL - 127 IS - 6 N2 - Testosterone (T) inhibits GnRH secretion and can also modulate the effects of GnRH on gonadotropin synthesis and secretion. To assess the effect of T on GnRH stimulation of alpha, LH beta, and FSH beta mRNA expression, we replaced T at three levels to reproduce low (1.5 +/- 0.5 ng/ml), medium (3.5 +/- 0.3 ng/ml), and high (6.2 +/- 0.6 ng/ml) physiological plasma concentrations. Additionally, as peripheral conversion to dihydrotestosterone (DHT) or estradiol (E2) may mediate T action, the effects of GnRH pulses in the presence of DHT and E2 were also studied. Male rats were castrated, and steroids were replaced via implants containing either T (three doses) or DHT or E2 (two doses each). GnRH pulses (10-250 ng/pulse) were administered iv at 30-min intervals for 48 h. Pituitary subunit mRNA concentrations, gonadotropin content, and LH and FSH secretion were determined. The patterns of alpha, LH beta, and FSH beta mRNA responses to increasing GnRH pulse amplitude were similar at all concentrations of plasma T. Alpha mRNA concentrations were increased 2- to 4-fold by GnRH pulses. At the same plasma T concentration, all doses of GnRH produced similar increases in alpha mRNA, but the response tended to be lower at the higher (6.2 ng/ml) levels of T. LH beta mRNA showed a clear dependence on GnRH pulse amplitude, with the maximum responses (2- to 3-fold) occurring after 10- to 25-ng GnRH pulses. At the higher (3.5 and 6.2 ng/ml) T concentrations, the dose-response curve was shifted to the left. The lowest GnRH pulse dose (10 ng) produced maximum responses, and LH beta mRNA increments in response to the higher GnRH doses were suppressed. FSH beta mRNA concentrations were increased by T in saline-pulsed controls. FSH beta mRNA responses were similar (2- to 3-fold) after all GnRH doses and at all concentrations of T. Increasing GnRH pulse doses reduced the pituitary content of both LH and FSH at all levels of T. Acute LH secretion was maximal after 10- and 25-ng pulses of GnRH when plasma T was low, but increased progressively with GnRH dose at the highest plasma T concentrations. Plasma FSH did not show any differential responsiveness to GnRH pulse dose or to increasing plasma T. Thus, LH synthesis and secretion are affected more than those of FSH by changing plasma concentrations of T. T may modulate posttranslational events in LH secretion. The higher GnRH doses effected LH release without increasing LH beta mRNA in the presence of higher physiological concentrations of T.(ABSTRACT TRUNCATED AT 400 WORDS) SN - 0013-7227 UR - https://www.unboundmedicine.com/medline/citation/1701131/Testosterone_differentially_modulates_gonadotropin_subunit_messenger_ribonucleic_acid_responses_to_gonadotropin_releasing_hormone_pulse_amplitude_ L2 - https://academic.oup.com/endo/article-lookup/doi/10.1210/endo-127-6-2876 DB - PRIME DP - Unbound Medicine ER -