Abstract
In this study, we have investigated the effect of combined treatment using two somatostatin
analogs, lanreotide or octreotide, with bromocriptine on GH release in cultures of
GH-secreting pituitary tumors. Sixteen acromegalic patients were included in the study.
All patients had been treated with lanreotide prior to the surgery. Five patients
(31.2 %) reached GH levels below 2.0 µg/l and normal IGF-I levels according to age
and sex after lanreotide treatment. A positive correlation was observed between the
lanreotide-induced inhibition of GH release in vitro and serum GH decrease after lanreotide treatment (r = 0.52; p = 0.03). Combined treatment
significantly inhibited GH release in vitro in 8 of the 16 tumors (50 %). However, only 5 (31.2 %) of the respective patients
had been resistant to presurgical treatment with lanreotide. Three of these 5 patients
(18.7 %) responded to a BC concentration similar to that achieved with therapeutic
doses, and in 2 patients only when a pharmacological dose of BC was used in the combined
treatment. The additive effect was observed with the combination of lanreotide and
BC in 6 tumors and with octreotide and BC in 3. Only one tumor showed simultaneous
response to both types of combination. These results suggest that the additive effect
under the combined treatment might be found between 18 and 30 % of patients who are
resistant to these drugs, and that different combinations of somatostatin analogs
and dopamine agonists should be tested in resistant patients.
Key words
Acromegaly - Bromocriptine - Somatostatin Analogs
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J. Antonio Balsa, M.D.
Servicio de Endocrinología · Hospital Ramón y Cajal
Carretera de Colmenar Km 9 · 28034 Madrid · Spain ·
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