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Altered dopaminergic regulation of thyrotrophin release in patients with prolactinomas: comparison with other tests of hypothalamic-pituitary function.
Clin Endocrinol (Oxf). 1981 Feb; 14(2):133-43.CE

Abstract

This study was carried out to test the hypothesis that sustained hyperprolactinaemia in patients with prolactinomas stimulates hypothalamic dopaminergic activity via a short loop positive feedback effect of prolactin (PRL). The intensity of dopamine (DA) effects on the pituitary around the adenoma was evaluated by measuring thyroid stimulating hormone (TSH) responses to intravenous injection of domperidone (10 mg) a new DA receptor blocking drug that does not penetrate the blood-brain barrier. TSH responses have been compared with those of PRL to the same agent. Eight females with prolactinomas showed greater TSH release after domperidone than nine normal females (sum of TSH increments over 20 min 17.5 +/- 1.7 v. 8.9 +/- 1.5 mu/l, P less than 0.001) whilst PRL release was reduced (sum of PRL increments over 120 min 5.9 +/- 2.4 v. 21.8 +/- 3.8 mu/l x 10(-3), P less than 0.01). Amongst nineteen hyperprolactinaemic females with apparently normal pituitary fossae (plain skull X-ray), ten showed an exaggerated TSH response (delta TSH, 4.2 +/- 0.6 mu/l, range 2.5-9.0 mu/1) and reduced PRL response to domperidone, comparable with established tumor cases. In the remaining nine normal fossa hyperprolactinaemic females, the TSH and PRL responses to dopaminergic were similar to normal females. These results support the initial hypothesis and indicate the coexistence of a defect in the dopaminergic inhibition of PRL release and increased dopaminergic inhibition of TSH release in patients with prolactinomas. The presence of an exaggerated TSH response to DA antagonism in a euthyroid, radiologically normal (plain skull X-ray), hyperprolactinaemic patient is compatible with the presence of an autonomously-functioning, PRL secreting, pituitary microadenoma and the TSH changes seen in these patients after DA antagonist administration can be readily detected by sensitive TSH radioimmunoassay.

Authors

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

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

6790201

Citation

Scanlon, M F., et al. "Altered Dopaminergic Regulation of Thyrotrophin Release in Patients With Prolactinomas: Comparison With Other Tests of Hypothalamic-pituitary Function." Clinical Endocrinology, vol. 14, no. 2, 1981, pp. 133-43.
Scanlon MF, Rodriguez-Arnao MD, McGregor AM, et al. Altered dopaminergic regulation of thyrotrophin release in patients with prolactinomas: comparison with other tests of hypothalamic-pituitary function. Clin Endocrinol (Oxf). 1981;14(2):133-43.
Scanlon, M. F., Rodriguez-Arnao, M. D., McGregor, A. M., Weightman, D., Lewis, M., Cook, D. B., Gomez-Pan, A., & Hall, R. (1981). Altered dopaminergic regulation of thyrotrophin release in patients with prolactinomas: comparison with other tests of hypothalamic-pituitary function. Clinical Endocrinology, 14(2), 133-43.
Scanlon MF, et al. Altered Dopaminergic Regulation of Thyrotrophin Release in Patients With Prolactinomas: Comparison With Other Tests of Hypothalamic-pituitary Function. Clin Endocrinol (Oxf). 1981;14(2):133-43. PubMed PMID: 6790201.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Altered dopaminergic regulation of thyrotrophin release in patients with prolactinomas: comparison with other tests of hypothalamic-pituitary function. AU - Scanlon,M F, AU - Rodriguez-Arnao,M D, AU - McGregor,A M, AU - Weightman,D, AU - Lewis,M, AU - Cook,D B, AU - Gomez-Pan,A, AU - Hall,R, PY - 1981/2/1/pubmed PY - 1981/2/1/medline PY - 1981/2/1/entrez SP - 133 EP - 43 JF - Clinical endocrinology JO - Clin Endocrinol (Oxf) VL - 14 IS - 2 N2 - This study was carried out to test the hypothesis that sustained hyperprolactinaemia in patients with prolactinomas stimulates hypothalamic dopaminergic activity via a short loop positive feedback effect of prolactin (PRL). The intensity of dopamine (DA) effects on the pituitary around the adenoma was evaluated by measuring thyroid stimulating hormone (TSH) responses to intravenous injection of domperidone (10 mg) a new DA receptor blocking drug that does not penetrate the blood-brain barrier. TSH responses have been compared with those of PRL to the same agent. Eight females with prolactinomas showed greater TSH release after domperidone than nine normal females (sum of TSH increments over 20 min 17.5 +/- 1.7 v. 8.9 +/- 1.5 mu/l, P less than 0.001) whilst PRL release was reduced (sum of PRL increments over 120 min 5.9 +/- 2.4 v. 21.8 +/- 3.8 mu/l x 10(-3), P less than 0.01). Amongst nineteen hyperprolactinaemic females with apparently normal pituitary fossae (plain skull X-ray), ten showed an exaggerated TSH response (delta TSH, 4.2 +/- 0.6 mu/l, range 2.5-9.0 mu/1) and reduced PRL response to domperidone, comparable with established tumor cases. In the remaining nine normal fossa hyperprolactinaemic females, the TSH and PRL responses to dopaminergic were similar to normal females. These results support the initial hypothesis and indicate the coexistence of a defect in the dopaminergic inhibition of PRL release and increased dopaminergic inhibition of TSH release in patients with prolactinomas. The presence of an exaggerated TSH response to DA antagonism in a euthyroid, radiologically normal (plain skull X-ray), hyperprolactinaemic patient is compatible with the presence of an autonomously-functioning, PRL secreting, pituitary microadenoma and the TSH changes seen in these patients after DA antagonist administration can be readily detected by sensitive TSH radioimmunoassay. SN - 0300-0664 UR - https://www.unboundmedicine.com/medline/citation/6790201/Altered_dopaminergic_regulation_of_thyrotrophin_release_in_patients_with_prolactinomas:_comparison_with_other_tests_of_hypothalamic_pituitary_function_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0300-0664&date=1981&volume=14&issue=2&spage=133 DB - PRIME DP - Unbound Medicine ER -