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The influence of long-term low dose thyrotropin-releasing hormone infusions on serum thyrotropin and prolactin concentrations in man.
J Clin Endocrinol Metab. 1980 Oct; 51(4):771-5.JC

Abstract

The purpose of the present study was to evaluate in man the relative thyrotroph and lactotroph response to a 48-h low dose constant TRH infusion. Before, during, and after the 75 ng/min TRH constant infusion, serum samples were obtained every 4 h in six euthyroid ambulating male subjects for measurements of TSH, PRL, T4, and T3. The TSH response, employing a specific and sensitive human TSH RIA, demonstrated a significant rise from the mean basal pre-TRH value of 2.35 +/- 0.64 microU/ml (+/- SEM) to 3.68 +/- 0.80 (P < 0.005) during the TRH infusion; this value fell below the basal level to 1.79 +/- 0.47 (P < 0.05) post infusion. Serum T4 values were increased above basal both during (P < 0.025) and after (P < 0.025) TRH infusion, whereas serum T3 values were not significantly changed throughout the entire study period. The daily TSH nocturnal surge was augmented in both absolute and relative terms during the first 24 h or the TRH infusion, unchanged during the second 24 h of infusion, and inhibited during the first postinfusion day. Other than a minimal increase in serum PRL during the first few hours of the infusion, no significant alteration in the mean basal concentration or circadian pattern of PRL secretion was evident during or after the low dose TRH infusion. These findings would indicate that 1) near-physiological stimulation of the pituitary with TRH produces a greater stimulation of TSH release than of PRL release and 2) the factor or factors producing the circadian TSH surge may not be mediated through fluctuations in endogenous TRH.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

6774994

Citation

Spencer, C A., et al. "The Influence of Long-term Low Dose Thyrotropin-releasing Hormone Infusions On Serum Thyrotropin and Prolactin Concentrations in Man." The Journal of Clinical Endocrinology and Metabolism, vol. 51, no. 4, 1980, pp. 771-5.
Spencer CA, Greenstadt MA, Wheeler WS, et al. The influence of long-term low dose thyrotropin-releasing hormone infusions on serum thyrotropin and prolactin concentrations in man. J Clin Endocrinol Metab. 1980;51(4):771-5.
Spencer, C. A., Greenstadt, M. A., Wheeler, W. S., Kletzky, O. A., & Nicoloff, J. T. (1980). The influence of long-term low dose thyrotropin-releasing hormone infusions on serum thyrotropin and prolactin concentrations in man. The Journal of Clinical Endocrinology and Metabolism, 51(4), 771-5.
Spencer CA, et al. The Influence of Long-term Low Dose Thyrotropin-releasing Hormone Infusions On Serum Thyrotropin and Prolactin Concentrations in Man. J Clin Endocrinol Metab. 1980;51(4):771-5. PubMed PMID: 6774994.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The influence of long-term low dose thyrotropin-releasing hormone infusions on serum thyrotropin and prolactin concentrations in man. AU - Spencer,C A, AU - Greenstadt,M A, AU - Wheeler,W S, AU - Kletzky,O A, AU - Nicoloff,J T, PY - 1980/10/1/pubmed PY - 1980/10/1/medline PY - 1980/10/1/entrez SP - 771 EP - 5 JF - The Journal of clinical endocrinology and metabolism JO - J Clin Endocrinol Metab VL - 51 IS - 4 N2 - The purpose of the present study was to evaluate in man the relative thyrotroph and lactotroph response to a 48-h low dose constant TRH infusion. Before, during, and after the 75 ng/min TRH constant infusion, serum samples were obtained every 4 h in six euthyroid ambulating male subjects for measurements of TSH, PRL, T4, and T3. The TSH response, employing a specific and sensitive human TSH RIA, demonstrated a significant rise from the mean basal pre-TRH value of 2.35 +/- 0.64 microU/ml (+/- SEM) to 3.68 +/- 0.80 (P < 0.005) during the TRH infusion; this value fell below the basal level to 1.79 +/- 0.47 (P < 0.05) post infusion. Serum T4 values were increased above basal both during (P < 0.025) and after (P < 0.025) TRH infusion, whereas serum T3 values were not significantly changed throughout the entire study period. The daily TSH nocturnal surge was augmented in both absolute and relative terms during the first 24 h or the TRH infusion, unchanged during the second 24 h of infusion, and inhibited during the first postinfusion day. Other than a minimal increase in serum PRL during the first few hours of the infusion, no significant alteration in the mean basal concentration or circadian pattern of PRL secretion was evident during or after the low dose TRH infusion. These findings would indicate that 1) near-physiological stimulation of the pituitary with TRH produces a greater stimulation of TSH release than of PRL release and 2) the factor or factors producing the circadian TSH surge may not be mediated through fluctuations in endogenous TRH. SN - 0021-972X UR - https://www.unboundmedicine.com/medline/citation/6774994/The_influence_of_long_term_low_dose_thyrotropin_releasing_hormone_infusions_on_serum_thyrotropin_and_prolactin_concentrations_in_man_ L2 - https://academic.oup.com/jcem/article-lookup/doi/10.1210/jcem-51-4-771 DB - PRIME DP - Unbound Medicine ER -