Growth Hormone and Prolactin Secretion after Metoclopramide Administration (DA2 Receptor Blockade) in Fertile Women[*]

In this report, we will describe the results of a cross-sectional study to assess PRL and GH secretion during the early follicular phase in 22 fertile patients after metoclopramide administration in order to achieve a dopaminergic DA2 receptor blockade. Blood samples were collected at - 15, 0, 15, 30, 45 and 60 minutes. PRL, GH, estradiol, IGF-I, TSH, glucose, and insulin were measured in the samples taken at - 15 and 0 minutes. The existence of a correlation between GH and PRL secretion was investigated. All patients presented normal serum levels of estradiol, prolactin, insulin, fasting glucose and IGF-I. Serum GH levels were not changed after metoclopramide infusion (p = 0.302), but there was a significant alteration in serum PRL (p = 0.0001) with the highest levels after 30 (mean: 237.20 ng/ml ± 95.86) and 45 (mean: 211.80 ng/ml ± 83.24) minutes. Serum GH levels did not correlate with serum PRL levels after the dopaminergic DA2 blockade. We conclude that GH secretion was not modulated by a direct effect of type 2 dopamine receptor.

Key words:

GHRH - Somatostatin - GH Secretion - Dopamine DA2 Receptor - Metoclopramide Administration

1 This research was supported by grants from the Post-Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul, and Grupo de Pesquisa e Pós-Graduação, Hospital de Clinicas de Porto Alegre, Brazil.

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1 This research was supported by grants from the Post-Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul, and Grupo de Pesquisa e Pós-Graduação, Hospital de Clinicas de Porto Alegre, Brazil.