ergoline and Hyperthyroidism

A 2-year-old intact miniature pinscher bitch that had been on a bones and raw foods diet since birth showed no signs of estrus despite a 40-day course of cabergoline. Elevated levels of thyroxine were detected in the serum (51 nmol/L) and in the juice of the meat (183 nmol/L) fed to the dog. Change in diet and treatment with oral cabergoline resulted in signs of proestrus in 13 d, pregnancy, and normal birth of 5 puppies.

Topics: Administration, Oral; Anestrus; Animal Feed; Animals; Cabergoline; Diagnosis, Differential; Dog Diseases; Dogs; Ergolines; Female; Humans; Hyperthyroidism; Pedigree; Pregnancy; Pregnancy, Animal; Thyroxine

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.

Topics: Adenoma; Adenylyl Cyclases; Dopamine; Dose-Response Relationship, Drug; Ergolines; Female; Humans; Hyperthyroidism; In Vitro Techniques; Middle Aged; Pituitary Neoplasms; Radioimmunoassay; Somatostatin; Thyrotropin

A 12-yr-old girl with the syndrome of hyperthyroidism due to inappropriate TSH secretion, who had no evidence of pituitary tumor, was studied in detail. She had undergone two thyroidectomies for recurrent goiter and hyperthyroidism before referral. Basal serum TSH levels were extremely high (maximum 173 microU/ml), and the TSH response to TRH was exaggerated (peak, 675 microU/ml). The serum alpha-subunit of TSH was normal. PRL and other anterior pituitary hormone studies were normal. Dopamine infusion at 2 and 4 micrograms/kg X min partially suppressed TSH and PRL secretion and their responses to TRH. Bromocriptine had a paradoxical effect, resulting in an increase in TRH-stimulated TSH levels. Pergolide, a newer dopamine agonist, significantly decreased per basal serum TSH and blunted the TSH response to TRH; however, despite progressive dose increases, her TSH level was not reduced to normal.

Topics: Child; Dopamine; Ergolines; Female; Humans; Hyperthyroidism; Pergolide; Thyrotropin; Thyrotropin-Releasing Hormone

Topics: Adrenergic alpha-Antagonists; Ergolines; Evaluation Studies as Topic; Humans; Hyperthyroidism; Nicotinic Acids

Topics: Animals; Cardiovascular Agents; Ergolines; Ergot Alkaloids; Guinea Pigs; Hydrogenation; Hyperthyroidism