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The prolactin secretory response to neuroleptic drugs: Mechanisms, applications and limitations

1980; Elsevier BV; Volume: 5; Issue: 2 Linguagem: Inglês

10.1016/0306-4530(80)90015-3

1873-3360

Robert T. Rubín, Sally E. Hays,

Schizophrenia research and treatment

Neuroleptics, being dopamine (DA) receptor blockers, increase prolactin (PRL) secretion. Measurement of increased serum PRL has been proposed as an ‘in vivo bioassay’ in psychiatric patients for the concentration of neuroleptic binding to anterior pituitary lactotroph DA receptors, and, by inference, to other psychoactive CNS sites (e.g. mesolimbic DA receptors). However, the clinical applicability of this hormone test has yet to be demonstrated. One difficulty is the extreme sensitivity of the lactotroph DA receptors, such that clinically effective neuroleptic doses may stimulate PRL secretion maximally, thereby necessitating subclinical low-dose paradigms for establishing drug dose-PRL response curves. Another difficulty is the large interindividual variability in PRL secretion profiles, even in normal non-psychotic volunteers given neuroleptics intravenously. Thus, for comparative purposes, extended serial blood sampling protocols must be conducted over several hours to fully characterize PRL secretion profiles. Such sampling schedules may not be practical in acutely psychotic patients. Additionally, the effect of a neuroleptic drug at the pituitary lactotroph may not reflect its antipsychotic effect in the CNS; such relationships need to be demonstrated for different categories of neuroleptic drugs. And, finally, neuroleptics developed in the future may not work primarily by DA receptor blockade, so that PRL secretion would be of little utility as an ‘in vivo bioassay’ for these new drugs.