Neuroleptics consistently increase prolactin release by blocking the inhibitory action of DA on pituitary lactotropes. This may result in galactorrhea and gynecomastia. They reduce gonadotropin secretion but amenorrhea and infertility occur only occasionally. ACTH release in response to stress is diminish corticosteroids levels fail to increase under such circumstances. Release of GH is also reduced but this is not sufficient to cause growth retardation in children or to be beneficial in acromegaly. Decreased release of ADH may result in an increase in urine volume. A direct action on kidney tubules may add to it, but Na+ excretion is not affected.

7.Tolerance and dependence

Tolerance to the sedative and hypotensive actions develops within days or weeks, but maintenance doses in most psychotics remain fairly unchanged over years, despite increased DA turnover in the brain. The antipsychotic, extrapyramidal and other actions based on DA antagonism do not display tolerance.