Renner U, Mojto J, Lange M, Albrecht Müller O. von Werder K, Stalla GK. Effect of bromocriptine and SMS 201-995 on growth of human somatotrophic and non-functioning pituitary adenoma cells in vitro. Eur J Endocrinol 1994;130:80–91. ISSN 0804–4643
The effect of the dopamine agonist bromocriptine and the somatostatin analog SMS 201-995 on growth of 12 human somatotrophic and 13 non-functioning adenoma cell cultures was investigated. When adenoma cells were maintained in medium supplemented with 5% fetal calf serum. cell counts of 10 of 12 somatotrophic cultures increased to 145±6 and 171 ±9% (mean±sd) and in 12 of 13 non-functioning cell cultures up to 125±12 and 217±15% after 3 days of incubation. In most cases bromocriptine and SMS 201-995 dose dependently (1 nmol/l to 10 μmol/l) inhibited adenoma cell growth but there was only (1.10 μmol/l) a significant inhibitory effect at high doses of both drugs. A 1 μmol/l concentration of bromocriptine decreased cell counts of 5 of 12 somatotrophic cell cultures (range 84±3 to 76±6% vs control = 100%) and in 5 of 13 non-functioning cell cultures (range 85±4 to 71 ± 7%). A 10 μmol/l concentration of bromocriptine decreased cell counts in all 12 somatotrophic (range 87±1 to 61 ±8%) and in 12 of 13 non-functioning adenoma cultures (range 87±6 to 57±3%). Bromocriptine specifically inhibited growth because its effect could be reversed by the dopamine D2-receptor antagonist haloperidol. Both 1 and 10 μmol/l SMS 201-995 significantly decreased cell counts in three of six somatotrophic (87± 3 to 38 ±3%) cell cultures. In two of five cases growth of non-functioning adenoma cultures was suppressed by 1 μmol/ISMS 201-995, and in four of five cases by 10 μmol/l(86± 3 to 74 ±4%). The growth inhibitory effect of both bromocriptine and SMS 201-995 was not just due to an effect on growth of fibroblasts contaminating the adenoma cell cultures, because it could be observed also when adenoma cells were maintained in a d-valine-supplemented medium that suppresses fibroblast growth. In summary, both bromocriptine and SMS 201-995 at high doses were able to inhibit cell growth of cultured somatotrophic and non-functioning adenomas in vitro. However, the mechanism of this inhibitory effect is not yet well understood.
Ulrich Renner, Max-Planck-Institute of Psychiatry, Clinical Institute, Kraepelinstr. 10, D-80804 Munich, Germany