Journal of Clinical Endocrinology & Metabolism, Vol 59, 542-546, Copyright © 1984 by Endocrine Society

ARTICLES

Paradoxical response of thyrotropin to L-dopa and presence of dopaminergic receptors in a thyrotropin-secreting pituitary adenoma

P Chanson, J Orgiazzi, PJ Derome, D Bression, CP Jedynak, J Trouillas, P Legentil, J Racadot and F Peillon

We studied the dopaminergic control of TSH secretion in a patient with hyperthyroidism due to a TSH-secreting pituitary adenoma. A 34-yr-old previously thyroidectomized woman had mild clinical hyperthyroidism and a diffuse goiter without exophthalmos. She complained of headaches and had bitemporal hemianopsia. Serum T4 and T3 by RIA were elevated, and TSH was 112 microU/ml (normal range, 1.1-7.2). The alpha-subunit to TSH molar ratio was 1.7 (normal, less than 1), as reported in other patients with tumoral TSH hypersecretion. After TRH, a marked increase in TSH occurred. There was no evidence of pituitary deficiency. Skull x- rays and computerized axial tomography revealed an intrasellar tumor with suprasellar extension. Selective transsphenoidal adenomectomy was performed, and a pituitary tumor was removed. The tumor was almost entirely composed of cells reactive with antihuman beta TSH serum by indirect immunofluorescence. A unique feature of this patient was the marked increase in TSH levels after L-dopa administration. To our knowledge, this paradoxical response has never been reported previously in such patients. Using [3H]domperidone as ligand, dopaminergic receptors were demonstrated in the membranes of the adenomatous thyrotroph cells. The reason for the paradoxical response of TSH to dopaminergic agents is not known.

This article has been cited by other articles:

				T. Kienitz, M. Quinkler, C. J Strasburger, and M. Ventz Long-term management in five cases of TSH-secreting pituitary adenomas: a single center study and review of the literature Eur. J. Endocrinol., July 1, 2007; 157(1): 39 - 46. [Abstract] [Full Text] [PDF]