This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by CAMANNI, F. Articles by MOLINATTI, G. M. Search for Related Content PubMed PubMed Citation Articles by CAMANNI, F. Articles by MOLINATTI, G. M.

Effect of Dopamine on Plasma Growth Hormone and Prolactin Levels in Normal and Acromegalic Subjects

Cattedra di Endocrinologia, Universita' di Torino Italy

In contrast with other dopaminergic drugs (L-dopa, apomorphine or bromocriptine) a 280 µg/min dose of dopamine infused for 120 min failed to induce an increase in plasma GH in 9 normal subjects. During dopamine infusion, no significant change in the GH response to arginine was also noted, whereas prolactin displayed a significant fall.

In 15 acromegalic patients, on the other hand, the drug caused a marked fall in both GH (mean ± SE: 71.1% ± 5.6) and prolactin (mean ± SE: 67.6% ± 4.0), followed by a distinct rebound after the end of the test.

There was a very close relation (P < 0.001) between the maximum per cent decrease in GH during dopamine and after 2.5 mg bromocriptine by mouth. Dopamine also inhibited the GH response to TRH (4 patients).

Since dopamine does not readily cross the bloodbrain barrier, these results suggest that the stimulating effect of dopaminergic drugs on GH secretion in the normal subject is exerted via the CNS, whereas in acromegaly there is a direct action on structures lying outside the blood-brain barrier, probably in the hypophysis.

Dopaminergic inhibition of prolactin is primarily the result of action on the hypophysis, as well as on the hypothalamus, in both normal and acromegalic subjects.

Received July 27, 1976.

This article has been cited by other articles:

				P. Kok, F. Roelfsema, M. Frolich, J. van Pelt, A. E. Meinders, and H. Pijl Short-Term Treatment with Bromocriptine Improves Impaired Circadian Growth Hormone Secretion in Obese Premenopausal Women J. Clin. Endocrinol. Metab., September 1, 2008; 93(9): 3455 - 3461. [Abstract] [Full Text] [PDF]