Effects of bromocriptine on staining indices of Ki-67 and proliferating cell nuclear antigen, and nucleolar organizer region number in pituitary adenomas.

The effects of bromocriptine (CB-154) on the proliferative capacities of prolactinoma and somatotropinoma were investigated by immunocytochemical staining indices of proliferating cell nuclear antigen (PCNA) and Ki-67 (with MIB-1 antibody), and silver staining of nucleolar organizer region (NOR) number in histological sections. Patients with prolactinoma and somatotropinoma were divided into two groups: no preoperative treatment (control group), and treated with CB-154 for 2 weeks before adenomectomy (CB-154 group). The prolactinoma CB-154 group showed a significantly lower PCNA staining index (n = 6, 13.1 +/- 2.0%) and Ki-67 staining index (n = 6, 0.2 +/- 0.03%) than the control group (n = 4, 27.1 +/- 2.1%; n = 8, 1.9 +/- 0.5%; respectively) (p < 0.01). The somatotropinoma CB-154 group showed a significantly lower Ki-67 staining index (n = 5, 0.7 +/- 0.07%) than the control group (n = 11, 1.2 +/- 0.2%) (p < 0.05), but there was no significant difference in PCNA staining index (control: n = 5, 19.1 +/- 2.8% vs. CB-154: n = 5, 20.2 +/- 1.4%). However, variable intensities of PCNA staining between the cells were observed, resulting in an extraordinarily high staining index. NOR numbers did not vary significantly between the two prolactinoma groups (control: n = 4, 2.0 +/- 0.3 vs. CB-154: n = 6, 1.7 +/- 0.1) and two somatotropinoma groups (control: n = 5, 1.3 +/- 0.1 vs. CB-154: n = 5, 1.4 +/- 0.2).(ABSTRACT TRUNCATED AT 250 WORDS)