Exp Clin Endocrinol Diabetes 2006; 114 - P14_179
DOI: 10.1055/s-2006-933064

Effects of somatostatin and its analogues in primary cell cultures of adrenal tumors

B Ueberberg 1, MK Walz 2, N Unger 1, KW Schmid 3, K Mann 1, S Petersenn 1
  • 1Division of Endocrinology, Medical Center, University of Essen, Essen, Germany
  • 2Department of Surgery and Center of Minimally Invasive Surgery, Kliniken Essen-Mitte, Essen, Germany
  • 3Institute of Pathology, University of Essen, Essen, Germany

Aims: Somatostatin (SRIF) is a widely distributed peptide with effects on virtually all endocrine/exocrine secretions and cell proliferation in normal and tumor tissues. In a previous study, we demonstrated specific somatostatin receptor subtype (sst) expression profiles in various adrenal tumors using RT-PCR. Cortisol-producing adenomas (CPA) predominantly expressed sst2, 3 and 5. In aldosterone-producing adenomas (APA), expression of all 5 ssts was distributed equally and ranged from 45–65%. In this study, we investigated the effects of SRIF, octreotide (Oct) and the new multi-receptor ligand SOM230 (SOM) in primary cell cultures of CPA and APA.

Methods: Tissue from 5 CPA and 7 APA was obtained following minimally invasive surgery. Single-cell suspensions of the tumor tissues were prepared by enzymatic dissociation with collagenase. Cells were cultured in serum-free medium and incubated for 24–72h with and without the test hormones (10nM). Cortisol (C) and aldosterone (A) were measured in culture medium samples.

Results: Despite establishment of adherent single-cell cultures, hormone secretion could not be established in 60% and 42% of CPA and APA, respectively, possibly indicating misclassification as hormonally active adenomas. In CPA, ACTH stimulated C by 114%. In both tumors investigated, SRIF and Oct stimulated C by 33% and 49%, respectively, whereas SOM had no effect. In APA, angiotensine II (ANG) and ACTH stimulated A by 57% and 46%, respectively. Furthermore, Oct and SOM stimulated A in 2 tumors by 35% and 52%, respectively, whereas SRIF had no effect. These effects were established in 24h cultures and diminished with longer incubation periods.

Conclusions: In contrast to inhibition of endocrine secretion in most other cell systems, somatostatin and its analogues stimulated specific hormone secretion in some adrenal tumors. Ligand-specific responses in CAP and APA may depend on the sst expression profiles in these tumors.