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The value of plasma prolactin levels in the prediction of the responsiveness of growth hormone secretion to bromocriptine and TRH in acromegaly
Author(s) -
LAMBERTS S. W. J.,
LIUZZI A.,
CHIODINI P. G.,
VERDE S.,
KLIJN J. G. M.,
BIRKENHÁGER J. C.
Publication year - 1982
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1982.tb00952.x
Subject(s) - bromocriptine , acromegaly , prolactin , endocrinology , medicine , thyrotropin releasing hormone , hormone , secretion , prolactin cell , growth hormone , chemistry
. The mechanism of the inhibition of growth hormone secretion in response to bromocriptine and the ability of thyrotropin releasing hormone to stimulate growth secretion in acromegaly is unknown. In the present study the relationship between the plasma prolactin concentration of untreated acromegalic patients and the reaction of growth hormone to thyrotropin releasing hormone and bromocriptine was investigated. Plasma prolactin levels were elevated in thirty‐three (42%) of seventy‐nine untreated acromegalic patients. Seventeen patients had mildly elevated prolactin levels, but in sixteen the plasma prolactin concentration was higher than 30 ng/ml. Bromocriptine (2.5 mg) inhibited growth hormone secretion by more than 50% in 22% of the normoprolactinaemic, in 53% of the mild hyperprolactinaemic and in 88% of the patients with a prolactin level above 30 ng/ml ( P <0.01 v. normoprolactinaemic; P <0.01 v. mildly elevated prolactin levels). An increase of growth hormone secretion by more than 100% of the basal value in response to thyrotropin releasing hormone was observed in 44% of the normoprolactinaemic, in 59% of the mildly hyperprolactinaemic and in 75% of the clearly hyperprolactinaemic patients; ( P <0.01 v. normo‐and mildly hyperprolactinaemic patients). Conclusion: An increased plasma prolactin concentration in patients with acromegaly is accompanied in most patients by a higher sensitivity of growth hormone secretion to bromocriptine.