The Role of Serotonin and Dopamine in Hypothalamic‐pituitary Function

Neuroendocrinology has developed as a major discipline out of the important early concepts of Harris (1948) and the subsequent findings in the early 1960's demonstrating that the brain and, in particular, the hypothalamus, exerted an inhibitory influence on prolactin secretion (Pasteels, 1963;Talwalker et al., 1963;Danon et al., 1963) and a stimulating influence on growth hormone (GH) secretion from the pituitary gland (Roth et al., 1963; Abrams et al., 1964).That these hypothalamic influences were mediated by the brain monoamine transmitters was suggested from the findings of many groups (e.g.Kanematsu et al., 1963; Ratner et al., 1965; Muller et al., 1967; Blackard & Heidingsfelder, 1968; Van Maanen & Smelik, 1968) who used drugs such as reserpine and a-adrenergic blocking agents which interfere with the activity of the brain monoamines.The individual roles of specific monoamines in hypothalamic pituitary function have been investigated in diverse ways.The use of intraventricular injection of the amines dopamine, noradrenaline and serotonin in the rat has, despite its limitations (Hokfelt & Fuxe, 1972), laid much groundwork in this area (Schneider & McCann, 1970;Kamberi et al., 1970Kamberi et al., , 1971;;Marks et al., 1970;Collu et al., 1972).The development of fluorescence histochemistry (Corrodi & Jonsson, 1967;Fuxe et al., 1970) has enabled the localization of hypothalamic monoamine cell bodies to be established, as well as aspects of the function of amine neuronal groups such as the tuberoinfundibular dopaminergic (TIDA) neurons in the control of prolactin-and gonadotrophin secretion (Hokfelt & Fuxe, 1972).Another approach t o the problem of establishing in vivo the specific roles for the monoamines has been to use either precursors which produce specific monoamines, or drugs which selectively interfere with the activity of monoamines (Donoso el al., 1971;