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In vitro studies on TSH secretion and adenylate cyclase activity in a human TSH-secreting pituitary adenoma. Effects of somatostatin and dopamine.
J Endocrinol Invest. 1985 Jun; 8(3):193-8.JE

Abstract

We have studied the in vitro TSH secretion and the adenylate cyclase (AC) activity of a human pituitary adenoma surgically removed from a hyperthyroid patient showing high serum TSH levels. The tumor appeared almost homogeneously constituted by cells positive for an anti-TSH-beta antiserum and showing the ultrastructural characteristics of the adenomatous thyrotrophs. Adenoma fragments released in vitro a large amount of TSH (148.4 microU/mg prot/30 min), alpha-subunit (35.5 ng/mg prot/30 min) and TSH-beta (10.1 ng/mg prot/30 min). The effects of somatostatin (GHRIH) and dopamine (DA) on the hormone release have been tested in vitro. Both agents markedly inhibited the release of intact TSH and TSH-beta whereas the release of alpha-subunit was less affected. The two agents were effective at concentrations higher than 10(-8)M. The ability of GHRIH and DA in modulating the AC activity was investigated in membrane fraction preparations. GHRIH inhibited AC at concentrations higher than 10(-7)M. The maximal inhibition was 32% at 10(-5)M. Conversely, DA slightly stimulated AC activity. This effects was not mimicked by the dopaminergic ergot CH 29-717, which was completely ineffective on the enzyme. These results suggest that: 1) in this TSH-secreting pituitary adenoma a normal secretory response to the inhibiting agents (GHRIH and DA) is present; 2) different mechanisms of transduction of the GHRIH and DA signals (cAMP dependent and cAMP independent) could be operating in this tumor.

Authors

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Pub Type(s)

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

Language

eng

PubMed ID

2863299

Citation

Spada, A, et al. "In Vitro Studies On TSH Secretion and Adenylate Cyclase Activity in a Human TSH-secreting Pituitary Adenoma. Effects of Somatostatin and Dopamine." Journal of Endocrinological Investigation, vol. 8, no. 3, 1985, pp. 193-8.
Spada A, Bassetti M, Martino E, et al. In vitro studies on TSH secretion and adenylate cyclase activity in a human TSH-secreting pituitary adenoma. Effects of somatostatin and dopamine. J Endocrinol Invest. 1985;8(3):193-8.
Spada, A., Bassetti, M., Martino, E., Giannattasio, G., Beck-Peccoz, P., Sartorio, A., Vallar, L., Baschieri, L., Pinchera, A., & Faglia, G. (1985). In vitro studies on TSH secretion and adenylate cyclase activity in a human TSH-secreting pituitary adenoma. Effects of somatostatin and dopamine. Journal of Endocrinological Investigation, 8(3), 193-8.
Spada A, et al. In Vitro Studies On TSH Secretion and Adenylate Cyclase Activity in a Human TSH-secreting Pituitary Adenoma. Effects of Somatostatin and Dopamine. J Endocrinol Invest. 1985;8(3):193-8. PubMed PMID: 2863299.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In vitro studies on TSH secretion and adenylate cyclase activity in a human TSH-secreting pituitary adenoma. Effects of somatostatin and dopamine. AU - Spada,A, AU - Bassetti,M, AU - Martino,E, AU - Giannattasio,G, AU - Beck-Peccoz,P, AU - Sartorio,A, AU - Vallar,L, AU - Baschieri,L, AU - Pinchera,A, AU - Faglia,G, PY - 1985/6/1/pubmed PY - 1985/6/1/medline PY - 1985/6/1/entrez SP - 193 EP - 8 JF - Journal of endocrinological investigation JO - J Endocrinol Invest VL - 8 IS - 3 N2 - We have studied the in vitro TSH secretion and the adenylate cyclase (AC) activity of a human pituitary adenoma surgically removed from a hyperthyroid patient showing high serum TSH levels. The tumor appeared almost homogeneously constituted by cells positive for an anti-TSH-beta antiserum and showing the ultrastructural characteristics of the adenomatous thyrotrophs. Adenoma fragments released in vitro a large amount of TSH (148.4 microU/mg prot/30 min), alpha-subunit (35.5 ng/mg prot/30 min) and TSH-beta (10.1 ng/mg prot/30 min). The effects of somatostatin (GHRIH) and dopamine (DA) on the hormone release have been tested in vitro. Both agents markedly inhibited the release of intact TSH and TSH-beta whereas the release of alpha-subunit was less affected. The two agents were effective at concentrations higher than 10(-8)M. The ability of GHRIH and DA in modulating the AC activity was investigated in membrane fraction preparations. GHRIH inhibited AC at concentrations higher than 10(-7)M. The maximal inhibition was 32% at 10(-5)M. Conversely, DA slightly stimulated AC activity. This effects was not mimicked by the dopaminergic ergot CH 29-717, which was completely ineffective on the enzyme. These results suggest that: 1) in this TSH-secreting pituitary adenoma a normal secretory response to the inhibiting agents (GHRIH and DA) is present; 2) different mechanisms of transduction of the GHRIH and DA signals (cAMP dependent and cAMP independent) could be operating in this tumor. SN - 0391-4097 UR - https://www.unboundmedicine.com/medline/citation/2863299/In_vitro_studies_on_TSH_secretion_and_adenylate_cyclase_activity_in_a_human_TSH_secreting_pituitary_adenoma__Effects_of_somatostatin_and_dopamine_ L2 - https://link.springer.com/article/10.1007/BF03348476 DB - PRIME DP - Unbound Medicine ER -