They are released in response to appropriate physiological signals: ADH release is determined by blood osmolality, effective blood volume, and stress; oxytocin is released during labour and in response to suckling. Secretion of both hormones is mediated by neural reflexes that are also modulated by the hormonal milieu. ADH secretion is suppressed by glucocorticoids, while oxytocin secretion is stimulated by oestrogens.