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.

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

References

• 1 Katz E, Ricciarelli E, Adashi E Y. The potential relevance of growth hormone to female reproductive physiology and pathophysiology.  Fertil Steril. 1993;  59 8-34
• 2 Devesa J, Lima L, Tresguerres A F. Neuroendocrine control of growth hormone secretion in humans.  Trends Endocrinol Metab. 1992;  3 175-183
• 3 Argente J, Pozo J, Chowen J A. The growth hormone axis: control and effects.  Norm Res. 1996;  45 9-11
• 4 Multer E E, Folia M, Ghigo E, Belliti D, Arvat E, Andreoni  A, Torsello A, Locatelli V, Camanni F. Involvement of brain catecholamines and acetylcholine in growth hormone hypersecretory states. Pathophysiological, diagnostic and therapeutic implications.  Rugs. 1995;  50 805-37
• 5 Müller-Spahn F, Modell S, Ackenheil M, Brachner A, Kutz G. Elevated response of growth hormone to graded doses of apomorphine in schizophrenic patients.  J Psychiatr Res. 1998;  32 265-271
• 6 Vance M L, Kaiser  D L, Frohman L A, Rivier J, Vale W W, Thomer M O. Role of dopamine in the regulation of Growth Hormone secretion: dopamine and bromocriptine augment growth hormone-τ releasing hormone stimulated GH secretion in normal man.  J Clin Endocrinol Metab. 1987;  64 1136-1141
• 7 Arce V, Lima L, Lois N, Rodriguez A, Diaz M J, Tresguerres J A, Devesa J. Role of central dopaminergic pathways in the neural control of growth hormone secretion in normal men: studies with metoclopramide.  Neuroendocrinology. 1991;  53 143-149
• 8 Masala A, Delitala G, Alagna S, Devilla L, Rovasio P P, Lotti G. Effect of dopaminergic blockade on the secretion of growth hormone and prolactin in man.  Metabolism. 1978;  27 921-926
• 9 Cohen H N, Hay I D, Thonson J A, Logue F, Ratcliffe W A, Beastall G H. Metoclopramide stimulation: a test of growth hormone reserve in adolescent males.  Clin Endocrinol. 1979;  11 89-93
• 10 Chiodera P, Coiro V, Zanardi G, Volpi R, Valenti G, Butturini U. Effect of metoclopramide on serum GH levels in normal women.  Horm Metab Res. 1982;  14 103-104
• 11 Jordan V, Dieguez C, Lafaffian I, Rodriguez-Arnao M D, Gomez-Pan A, Hall R, Scanlon M F. Influence of dopaminergic, adrenergic and cholinergic blockade and TRH administration on GH responses to CRF 1-29.  Clin Endocrinol. 1986;  29 291-298
• 12 Volpi R, Coiro V, Salvi M, Pelosi G, Mancini P, Chiodera P. Effect of metoclopramide on serum growth hormone levels in cirrhotic men.  J Endocrinol Invest. 1983;  6 101-105
• 13 Fang V S, Shian L R. A serotonergic mechanism of the prolactin stimulating action of metoclopramide.  Endocrinology. 1981;  108 1622-1627
• 14 Andersen A N, Tabor A. PRL, TSH, GH and LH responses to metoclopramide and breast-feeding in normal and hyperprolactinemic women.  Acta Endocrinol. 1982;  100 177-183

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.