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THE HIGHER THE GROWTH HORMONE RESPONSE TO GROWTH HORMONE RELEASING HORMONE THE LOWER THE RESPONSE TO BROMOCRIPTINE AND THYROTROPHIN RELEASING HORMONE IN ACROMEGALY
Author(s) -
SMALS A. E. M.,
PIETERS G. F. F. M.,
SMALS A. G. H.,
HERMUS A. R. M. M.,
BENRAAD TH. J.,
KLOPPENBORG P. W. C.
Publication year - 1987
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1987.tb00837.x
Subject(s) - medicine , endocrinology , acromegaly , bromocriptine , growth hormone–releasing hormone , hormone , thyrotropin releasing hormone , basal (medicine) , somatotropic cell , bolus (digestion) , growth hormone , prolactin , insulin
SUMMARY In acromegaly a direct relationship has been demonstrated between GH responsiveness to TRH and to the dopaminergic agent bromocriptine (Br). Recent data show an inverse relationship between GH responsiveness to Br and to GH releasing hormone (GHRH), but not between the GH responses to GHRH and TRH. Thirty‐one acromegalic patients, 18 women and 13 men (age 46‐2 ±(SD) 13 years) were studied. Four patients had been treated, but all still had active disease. The GH responses to GHRH (hpGHRH 1‐44 Bachem 100 μg i.v. bolus), TRH (Thyroliberin, Hoechst 200 μg i.v. bolus) and Br (Parlodel 5 mg orally) were assessed in most of the patients. The GH responses to GHRH showed a wide interindividual variation (δGH 1‐995 ng/ml), which correlated significantly with the basal GH levels (r=+0.85, P <0.0001, n = 31). GH increments in response to GHRH were inversely related to the responses to Br, i.e. the lower the GH increase after GHRH the greater the GH decrease after Br ( r =−0.49, P <0.01, m = 30). This decrease correlated with the basal PRL level ( r =+0.45, P <0.02, n = 29) and also the GH response to TRH ( r =+0.66, P <0.0001, n = 30). An inverse correlation was also found between the GH responses to TRH and to GHRH ( r =−0.43, P < 0.02, n = 29). The data are consistent with the existence of GH‐secreting adenomas which are more sensitive to GHRH and less to Br and TRH (pure somatotroph adenomas) and of mixed (lactotroph‐like adenomas) responsive to TRH and Br but less responsive to GHRH.