Terguride was given orally in doses of 0.25 mg, 0.5 mg, and 1 mg.

Collagen synthesis activity was assessed by measuring the incorporation of [3H]proline as follows: 3 x 104 cells were seeded in 24-well plates and grown overnight in DMEM/F12 medium supplemented with 10% dialyzed fetal calf serum and penicillin/streptomycin. The medium was replaced with a low serum concentration of 0.5%. After 48 h the cells were incubated in DMEM/F12 supplemented with 10 mkM phenelzine (a nonselective monoamine oxidase inhibitor) and 0.6 mM ascorbic acid. 5-HT (in the absence and presence of terguride) and terguride alone were added. Terguride was added 30 min before 5-HT. Cells were then incubated for 48 h in the presence of 1 mkCi/ml [3H]proline. Cells were washed twice with ice-cold PBS before precipitation with ice-cold 10% trichloroacetic acid for 1 h at 4°C. The precipitates were solubilized in 0.3 N NaOH/0.1% SDS solution at 37°C under gentle agitation, mixed with scintillation cocktail, and measured in a beta-scintillation counter. Experiments were performed in triplicate or quadruplicate. Results are presented as fold-changes compared with untreated control cells.