Growth hormone and somatomedin levels in acromegalics treated with bromocriptine.

Abstract

The effects of varied doses of bromocriptine on the growth hormonesomatomedin axis have been studied in 6 acromegalic patients. The study last 9 months and during this time a maximum daily dose of bromocriptine of 60 mg was given to 3, 50 mg to 1 and 20 mg to the remaining 2 patients. In 2 of the 6 there was an excellent reduction in the growth hormone (GH) levels down to the normal range on doses as low as 5 and 10 mg bromocriptine. In these 2 the serum somatomedin activity (SM-act) decreased to 71 and 53% of the basal values and there was an excellent clinical response. A third patient showed moderate clinical improvement, a reduction in the mean GH level but not down to the normal range and a decrease in serum SM-act of 10%. The remaining 3 patients showed no significant changes in GH levels or serum SM-act but all had a good clinical response. We conclude that when the clinical and GH responses to bromocriptine are both excellent there is a significant decrease in serum SM-act. In addition there may be a good clinical response in the absence of any changes in the circulating GH levels or SM-act which suggests that part of the beneficial effects due to bromocriptine are mediated by mechanisms other than changes in the GH-somatomedin axis.