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CRITICAL STUDY OF THE GROWTH HORMONE RESPONSE TO DYNAMIC TESTS AND THE INSULIN GROWTH FACTOR ASSAY IN ACROMEGALY AFTER MICROSURGERY
Author(s) -
SCHAISON G.,
COUZINET B.,
MOATTI N.,
PERTUISET B.
Publication year - 1983
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.1365-2265.1983.tb00591.x
Subject(s) - acromegaly , medicine , endocrinology , somatomedin , insulin , somatotropic cell , hormone , pituitary adenoma , growth hormone , insulin like growth factor , growth factor , adenoma , receptor
SUMMARY Eighteen acromegalic patients were studied 8 months to 5 years after transsphenoidal selective adenomectomy in order to evaluate the most reliable criteria for assessing the efficacy of treatment. Dynamic growth hormone (GH) studies were performed after administration of oral glucose (OGTT), thyrotro‐phin‐releasing‐hormone (TRH) or l ‐dopa, and after insulin‐induced hypogly‐caemia. Insulin‐like growth factor (IGF) was measured by means of a competitive protein‐binding assay which detects all somatomedins, particularly those which are GH‐dependent. Of the 18 subjects reported in our study, five showed clinical symptoms of persistent acromegaly. After oral glucose, seven patients had minimum plasma GH levels above 5 ng/ml, five had GH levels between 5 and 2 ng/ml (three of whom maintained a positive GH response to TRH), and six had minimum plasma GH values below 2 ng/ml. Only the latter six patients had normal IGF levels; however, one was still responsive to TRH and three did not increase their GH plasma levels after insulin or l ‐dopa administration. Thus, our data suggest that the criteria used to assess the cure of acromegaly should be more rigorous than those generally applied. When plasma GH levels remain above 2 ng/ml after OGTT, it is doubtful that the cure is complete. A positive GH response to TRH after neurosurgery indicates incomplete removal of the adenoma. The lack of a GH response following insulin‐induced hypoglycaemia and l ‐dopa administration suggests that the initial somatotroph dysfunction persists. Finally, high plasma IGF levels point to residual GH overproduction. The definition of cure in acromegaly should involve stricter biochemical criteria than those currently in use.