Hormonal Neuroleptics

Aquatic frogs and toads probably need less toxin for defense than terrestrial forms. The compounds in the frogs mucus are thought to be neuroleptic, blocking dopamine receptors. They also possibly are antibacterial and aid wound repair, and they are known to elevate the level of prolactin, the amphibian Juvenile hormone (Barthalmus and Zielinski, 1988). 

Neuroendocrine effects of neuroleptic drugs include a rise in growth hormone, inappropriate ADH and prolactin secretion, and disturbances of sex hormones (SEDA-7, 67). Galactorrhea (SEDA-20, 43) and gynecomastia can follow the rise in prolactin. 

Sex differences in hormone concentrations have been investigated in 47 patients (21 men and 26 women) with schizophrenia or related psychoses who were using different neuroleptic drugs (757). The median daily dose and the median body weight-adjusted daily dose were twice as high in men as in women. However, neuroleptic drug-induced hyperprolactinemia was more frequent and occurred at a lower daily dose in women. The growth hormone concentration was normal in all patients. 

The hormone leptin is synthesized by adipocytes and is important in controlling body weight plasma leptin concentrations correlate with fat mass and insulin resistance. Leptin could be a link between obesity, insulin resistance syndrome, and treatment with some neuroleptic drugs. Plasma leptin concentrations are raised, regardless of weight, in patients taking clozapine (793). 

Hormonal changes resulting from neuroleptic treatment... 

Since neuroleptic drugs raise prolactin concentrations, there is concern that this may increase the risk of breast cancer. Although studies have failed to show an association, it would be best to avoid neuroleptic drugs in a patient with a hormone-dependent breast tumor. 

Advantages are that the route is reliable, suitable for irritant dmgs, and depot preparations (neuroleptics, hormonal contraceptives) can be used at monthly or longer intervals. Absorption is more rapid than following subcutaneous injection (soluble preparations are absorbed within 10-30 min). 

The mechanisms of weight gain are not known. Olanzapine, for example, affects at least 19 different receptor sites, may have reuptake inhibition properties, and may affect hormones such as prolactin. Animal models do not help to elucidate mechanisms, since they have not shown clear results some studies have shown weight gain with neuroleptic drugs in rats and others have not. 

The promotion of mammary development, lactation, and galactopoiesis requires growth hormone, ovarian estrogen (duct formation), ovarian progesterone (lobule-alveolar development), and adrenal corticoids, as well as prolactin and oxytocin. The secretion of prolactin is modified by snbstances that stimulate or block dopamine-receptor sites. Agents such as neuroleptics (chlorpromazine) may cause lactation in a nonpregnant woman. On the other hand,... 

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