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Acromegaly and Cushing's syndrome due to ectopic production of GHRH and ACTH by a thymic carcinoid tumour: in vitro responses to GHRH and GHRP-6
- Source :
- Clinical Endocrinology. 48:243-250
- Publication Year :
- 1998
- Publisher :
- Wiley, 1998.
-
Abstract
- A 50-year-old male presented with diabetes mellitus and Cushing's syndrome associated with a large mediastinal mass. The levels of serum cortisol were high (1500-1800 nmol/l) without diurnal variation. Plasma ACTH levels (200-250 ng/l) and urinary excretion of cortisol were also increased. The levels of these hormones did not change in response to stimulation with corticotrophin releasing hormone (CRH) or suppression with high doses of dexamethasone. The patient had an elevated baseline GH level (7.3 mU/l), and the levels of immunoreactive GH-releasing hormone (GHRH) in eight plasma samples were markedly increased (600-1500 ng/l). Circulating levels of IGF-1, chromogranin A and neuropeptide Y (NPY) were also increased. Computer-assisted tomography and octreotide scintigraphy revealed a large mediastinal tumour and metastases in the left supraclavicular fossa. During treatment with octreotide, the baseline GH level was decreased (to 4.4 mU/l), while the GH pulse height was unchanged. Surgical removal of most of the tumour tissue resulted in a further decrease in the baseline serum GH level to a value (1.6 mU/l) about 20% of that before treatment, while the pulse height and mean GH were affected to a lesser extent. Postoperatively, circulating levels of cortisol and IGF-1 decreased, and the patient exhibited clinical improvement. Histological examination showed a neuroendocrine tumour with characteristics consistent with a foregut carcinoid of thymic origin. Immunoreactive GHRH, ACTH and NPY, but not immunoreactive GH, were detected in 80-90% of the tumour cells and the three peptides appeared to be co-localized. In primary culture, cells from this tumour displayed calcium influx in response to GHRH or GH releasing peptide-6 (GHRP-6), while there were not such responses by cells from another carcinoid not producing GHRH, ACTH or NPY. These results demonstrate a rare case of ectopic production of GHRH, ACTH and NPY, and indicate that the tumour cells were responsive to GHRH and GHRP-6 as well as octreotide.
- Subjects :
- Male
endocrine system
medicine.medical_specialty
Endocrinology, Diabetes and Metabolism
Octreotide
Carcinoid Tumor
Peptide hormone
Growth Hormone-Releasing Hormone
chemistry.chemical_compound
Cushing syndrome
Endocrinology
Adrenocorticotropic Hormone
Internal medicine
Acromegaly
Chromogranins
Tumor Cells, Cultured
medicine
Humans
Neuropeptide Y
GHRP-6
Insulin-Like Growth Factor I
Cushing Syndrome
biology
business.industry
Chromogranin A
Thymus Neoplasms
Middle Aged
Neuropeptide Y receptor
medicine.disease
Hormones
chemistry
Growth Hormone
biology.protein
Calcium
business
Oligopeptides
hormones, hormone substitutes, and hormone antagonists
Hormone
medicine.drug
Subjects
Details
- ISSN :
- 13652265 and 03000664
- Volume :
- 48
- Database :
- OpenAIRE
- Journal :
- Clinical Endocrinology
- Accession number :
- edsair.doi.dedup.....3fad1921617681929a2c14cf95ecd11f
- Full Text :
- https://doi.org/10.1046/j.1365-2265.1998.3471213.x