Impaired XXXX responsiveness to @entity935 antagonists in acromegaly.

@entity1 @entity4089 @entity935 @entity3216 @entity4090 @entity2124 @entity2211 @entity13304
@entity4090 (PRL) and @entity2124 ( @entity2124 ) secretion have been evaluated in 17 acromegalic @entity1 following acute administration of two @entity935 (DA) receptor antagonists, i.e. @entity3216 ( @entity3216 ) and @entity2211 ( @entity13304 ). Six @entity1 had persistent @entity4089 . In 8 normoprolactinemic @entity1 , i.m. injection of 100 mg SULP elicited only a slight rise iN plasma PRL, which was strikingly lower than that SULP induced in control subjects. Likewise, an i.v. bolus injection of @entity13304 (4 mg) was barely effective to raise plasma PRL in the 11 normoprolactinemic and the 6 hyperprolactinemic @entity1 . @entity13304 was instead capable of inducing a clear-cut rise in plasma PRL in normoprolactinemic controls and in a group of subjects with puerperal @entity4089 . Neither drug affected @entity2124 secretion in acromegalic @entity1 . It is proposed that a defective tuberoinfundibular DA function or, alternatively, a diminished PRL reserve due to a decrease pituitary lactotroph mass may be responsible for the blunted PRL responsiveness of acromegalics. However, standing the paucity of present knowledge on the pituitary PRL secretory pool in acromegalics, neither hypothesis seems capable to account satisfactory for the reported results.
