Thyroidectomy Blocks Stress-Induced Prolactin Rise in Rats:

Maria José Ramalho; L. C. Reis; J. Antunes-Rodrigues; E. De-Castro-e-Silva

doi:10.1055/s-2007-1003363

Hormone and Metabolic Research, Inhaltsverzeichnis

Horm Metab Res 1992; 24(10): 462-465
DOI: 10.1055/s-2007-1003363

Originals Basic

Thyroidectomy Blocks Stress-Induced Prolactin Rise in Rats:

Role of the Central Serotonergic SystemMaria José Ramalho¹ , L. C. Reis² , J. Antunes-Rodrigues³ , E. De-Castro-e-Silva¹

¹Departamento de Fisiologia, Institute de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Bahia
²Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, Itaguaí, Rio de Janeiro
³Departamento de Fisiologia, Faculdade de Medicina de Ribeiråo Preto, Universidade de Såo Paulo, Ribeiråo Preto, Såo Paulo, Brazil

Abstract

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Summary

Thyroidectomized (TX) adult Wistar male rats and their sham-operated controls were submitted to immobilization stress during forty minutes. Thyroidectomy partially blocks stress-induced prolactin (PRL) secretion. Previous administration of MK 212, a serotonin agonist, reverts this picture. The effect of MK 212 is specifically due to its interaction with 5HT2 receptors, since the injection of LY 53857, a selective blocker of these receptors, 30 min before MK 212, prevents the effect of this serotonin agonist. LY 53857, injected alone, yields a partial blockade of PRL secretion during stress in sham-operated rats. TX rats receiving LY 53857 or saline have comparable low values of plasma PRL during stress. It is suggested that thyroidectomy disrupts the functional integrity of the central serotonergic pathways involved in the stress-induced PRL rise.

Key words

Thyroidectomy - Prolactin - Serotonin

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