Parallelism in the luteinizing hormone responses to opioid and dopamine antagonists in hyperprolactinemic women with pituitary microadenoma.
Endogenous opiate peptides are considered to inhibit LH secretion via a dopaminergic mechanism, and increased opioid inhibition of LH secretion has been found in some hyperprolactinemic women with a pituitary microadenoma. To assess the role of endogenous dopaminergic tone in the opioid regulation of LH secretion in such patients, LH responses to an opioid antagonist (naloxone) and a dopamine antagonist (metoclopramide) were determined in 11 women with a prolactinoma. Neither naloxone nor metoclopramide administration induced any change in serum LH levels in normal women during the early follicular phase. In contrast, 7 of the 11 hyperprolactinemic women responded to both antagonists with a significant increase in LH levels. The parallelism in the LH responses to both antagonists in these hyperprolactinemic patients lends further support to a functional link between opioid and dopamine regulation of LH secretion.
D000236:Adenoma / Q000097:blood / Q000150:complications; D000328:Adult; D018492:Dopamine Antagonists; D005260:Female; D006801:Humans; D006966:Hyperprolactinemia / Q000097:blood* / Q000209:etiology; D007986:Luteinizing Hormone / Q000378:metabolism*; D008787:Metoclopramide / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D010911:Pituitary Neoplasms / Q000097:blood / Q000150:complications; D011388:Prolactin / Q000097:blood
D018492:Dopamine Antagonists; D009270:Naloxone; D011388:Prolactin; D007986:Luteinizing Hormone; D008787:Metoclopramide