Effects of bromocriptine on experimental GH3 cell tumors.
Bromocriptine in concentrations up to 10(-4) M was studied for morphological and endocrinological effects upon the GH3 cell line as well as the GH1 and AtT-20 cell lines. The cells (10(5)/ml) were incubated with RPMI 1640 or in some experiments Dulbecco's Modified Eagle's Medium supplemented with 10% FCS. Bromocriptine was added in concentrations of 10(-4) to 10(-8) mol/L and aliquots of medium were obtained at 2 and 24 hs for the determination of growth hormone and prolactin. Significant reductions in concentrations of growth hormone and prolactin as well as cell number were observed with a concentration of bromocriptine of 10(-4) M at 24 hs. The electron microscopic appearance of GH3 cells treated with 10(-4) mol/L concentrations of bromocriptine for 24 hs demonstrated extensive and marked vacuolization in the cytoplasm which had already appeared 2 hs after treatment with bromocriptine. In bromocriptine-treated (10(-4) mol/L for 24 hs) GH1 cells and AtT-20 cells, the morphologic features were essentially unchanged, compared to the untreated group. Since many previous reports demonstrated a defective dopamine receptor system in GH3 cells, it must be concluded that bromocriptine has an extradopaminergic action which is selectively observed in GH3 cell.
Department of Internal Medicine (Section 1), Sapporo Medical College, Japan.
K
K
Kamijo
M
M
Sato
T
T
Saito
A
A
Yachi
T
T
Minase
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D013006:Growth Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism; D009994:Osmolar Concentration; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D011388:Prolactin / Q000037:antagonists & inhibitors / Q000378:metabolism; D014407:Tumor Cells, Cultured
D001971:Bromocriptine; D011388:Prolactin; D013006:Growth Hormone