DYNAMICS OF THE ACUTE EFFECTS OF OCTREOTIDE, BROMOCRIPTINE AND BOTH DRUGS IN COMBINATION ON GROWTH-HORMONE SECRETION IN ACROMEGALY

The separate and combined GH-lowering effects of single doses of octreotide and bromocriptine were assessed in 51 acromegalic patients on 4 occasions each 2 days apart. Patients received sequentially: placebo sc (N = 51), 50-mu-g octreotide sc (N = 51), 2.5 mg bromocriptine po (N = 40) or a combination of both drugs (N = 25). with octreotide, in 28 patients (55%) GH levels were suppressed to less than 5-mu-g/l and 39 of them (76.5%) had a 50% or greater decrease of their basal GH level from 2 to 6 h. During bromocriptine, GH values were suppressed to below 5-mu-g/l in 11 patients (27.5%) and reduced by 50% or more in 21 (52.5%). The combination of both drugs acutely suppressed GH levels to less than 2-mu-g/l in 32%, to less than 5-mu-g/l in 56%, and by more than 50% in 84% of patients. Octreotide produced a stronger and faster suppression of GH levels than bromocriptine in most patients. The combination of both drugs had an additive effect on the lowering of GH levels, especially between 7 and 10 h after drug administration. These results suggest that chronic therapy with a combination of both drugs may be as effective as therapy with higher doses of either compound alone. Albeit transient, octreotide caused a rapid near total suppression of insulin release in the morning, 15 to 45 min after administration. Postprandial glucose rise. between 2 and 3.5 h after breakfast was significantly higher during octreotide than on the control day.