Prolactin and TSH responses to TRH and to ECT in pre- and postmenopausal women with major depression

The patterns of prolactin and thyrotropin (TSH) release after thyrotropin-releasing hormone (TRH) (0.4 mg i.v.) and during the first session of a course of electroconvulsive treatment (ECT) were studied in women with major depression, 16 in pre- and 29 in postmenopausal status. The prolactin responses to both stimuli were lower in postmenopausal women, whereas the TSH responses were not different. The known correlation between the maximal prolactin response to ECT and the maximal response to TRH was significantly stronger in the group of premenopausal women (r = .8648, versus .4249 in the postmenopausal group, p < .02). A common underlying mechanism promoting prolactin release for both stimuli can be suggested, which diminishes after menopause, probably an influence of estradiol on the affinity of dopaminergic and serotonergic receptors. That mechanism does not interfere with the TSH release either by ECT or by TRH.