1. Receptor imaging with 111In-pentreotide and 123I-methoxybenzamide, and inhibition tests with octreotide and bromocriptine of mixed growth hormone/prolactin-secreting pituitary tumors
- Author
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N. Panza, P.F. Rambaldi, C Battista, Luigi Mansi, F. Schillirò, G. Ambrosio, Giuseppe Lucio Cascini, Panza, N, Rambaldi, Pier Francesco, Battista, C, Ambrosio, G, Cascini, Gl, Schilliro, F, and Mansi, L.
- Subjects
Adult ,Male ,medicine.medical_specialty ,Pituitary gland ,Pyrrolidines ,Contrast Media ,Octreotide ,Scintigraphy ,Dopamine agonist ,Iodine Radioisotopes ,Internal medicine ,Humans ,Medicine ,Pituitary Neoplasms ,Radionuclide Imaging ,Tomography ,Bromocriptine ,Pharmacology ,medicine.diagnostic_test ,business.industry ,Indium Radioisotopes ,Pituitary tumors ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Prolactin ,Endocrinology ,Somatostatin ,medicine.anatomical_structure ,Growth Hormone ,Benzamides ,business ,medicine.drug - Abstract
We have performed pituitary scintigraphy with 111In-pentreotide (OCT), a somatostatin analogue, and with metoxybenzamide (IBZM) by 123I-IBZM in two patients affected by mixed growth hormone/prolactin-secreting pituitary tumors. Short-term growth hormone (GH) inhibition by a single injection of OCT (100 micrograms s.c.), and short-term prolactin (PRL) inhibition by oral administration of 2.5 mg of bromocriptine (BCR), were also performed in both patients. The first patient, a 26 year old man, showed intense tumor uptake of 123I-IBZM scintigraphy, whereas 111In-OCT scintigraphy showed moderate tumor uptake. Five hours after the BCR inhibition test, a fall of 83% in PRL plasma levels (from 8,336 micrograms/L to 1,417 micrograms/L), and of 91.6% in GH plasma levels (from 39.5 micrograms/L to 3.3 micrograms/L) were observed. OCT inhibition test suppressed GH plasma levels from 36 micrograms/L to 3.5 micrograms/L. The patient was submitted to treatment with BCR and OCT. A dramatic shrinkage of the tumor was seen after six months of therapy. The lesion disappeared one year after the start of therapy. The second patient, a 64 year old man, showed intense uptake at 111In-OCT scintigraphy, while 123I-IBZM uptake was not observed. A test dose of BCR resulted in an acute fall of PRL (from 145 micrograms/L to 118 micrograms/L), but not of GH. A test dose of OCT decreased the GH plasma level from 61 micrograms/L to 4.5 micrograms/L. The patient was submitted to treatment with BCR and OCT that resulted in a computed tomography and magnetic resonance imaging decrease of 45% of tumor volume one year after the start of therapy. Our results suggest that both suppression tests with OCT and BCR, and scintigraphic studies in vivo with 123I-IBZM and 111In-OCT can be predictive for the effectiveness of therapies with dopamine agonists and/or SS-analogs in patients with mixed PRL/GH-secreting pituitary tumors. Further studies are required to evaluate the role of suppressive tests in selecting patients for appropriate clinical treatments.
- Published
- 1999