Table of Contents
Metal-Based Drugs
Volume 6, Issue 3, Pages 159-162

Effect of Acute and Chronic Oral Zinc Administration in Hyperprolactinemic Patients

1Division of Endocrinology and Metabolism, Department of Internal Medicine, Universidade de São Paulo, São Paulo, Brazil
2Division of Endocrinology and Metabolism, Department of Internal Medicine, Universidade de Brasília – DF, CP 4591, Brasília CEP 70919-970, DF, Brazil

Received 2 April 1999; Accepted 3 May 1999

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The inverse relationship between zinc (Zn++) and prolactin (PRL) was detected in in vitro studies, whereas in vivo results are contradictory. In order to evaluate this controversial subject we studied patients with hyperprolactinemia. Basal serum Zn++ levels and serum PRL response to acute and chronic oral Zn++ administration were evaluated in seven patients with prolactinomas and one with idiopathic hyperprolactinemia. Serum PRL levels did not change after acute oral Zn++ administration (37.5 mg), although Zn++ levels increased from 1.11±0.15 to 2.44±0.39μg/mL(P<0.05) . Zn++ administration (47.7 mg daily) during 60 days increased serum Zn++ levels from 1.11 ± 0.15 to 1.59 ± 0.58 μg/mL (p < 0.05) but caused no change in serum PRL levels. The TRH tolerance test (200 μg ) was performed before and after 60 days of Zn++ administration, and PRL response to TRH was unchangeable and similar in both tests. We concluded that acute or chronic Zn++ administration does not inhibit PRL secretion in basal condition or by TRH effect in hyperprolactinemic patients.