Neurotransmitters and the control of hypophyseal gonadal functions: possible implications of endocrine disrupters

The reports published so far may suggest that chemicals of plant origin or obtained by synthesis may influence the central mechanisms controlling gona dotrophin secretion through a variety of different mechanisms. Some compounds of herbal origin seem to affect the neuroendocrine system ac ting as oestrogens (zearalenone and genistein). Also some synthetic chemica ls seem to display an oestrogenic influence on the neuroendocrine system (t he pesticide chlordecone, some of the polychlorinated biphenyls and of the alkylphenol ethoxylates). However, other synthetic molecules may affect the central control of gonadotrophin secretion acting like anti-androgens (pes ticides like DDT, dioxin and vinclozolin) or by disrupting the adrenergic r egulation of the hypothalamo-pituitary-gonadal axis (the pesticides chlordi meform and thiram). These conclusions refer only to a few compounds and are largely based on in direct evidence; in many cases specific experiments are still to be perform ed. For many other chemicals the possible mechanism of action on the neuroe ndocrine system is still to be elucidated. However, the information collect ed so far seems to suggest that the influence exerted by environmental endo crine disrupters on the neuroendocrine system is more complex than previous ly anticipated.