Bromocriptine treatment over 12 years in acromegaly: effect on growth hormone and prolactin secretion

Abstract

Bromocriptine treatment over 12 years in acromegaly: effect on growth hormone and prolactin secretion. Acta Endocrinol 1992;126:247-52. ISSN 0001-5598 It is not known whether bromocriptine treatment in acromegaly can be implemented for a life-long period. To elucidate this problem, the secretory GH and PRL states of 12 patients with acromegaly were determined, before bromocriptine treatment, under therapy (15.0\m=+-\6.8mg/day for 12\m=+-\3 years; mean\m=+-\sd) and during two-weeks long drug withdrawal after long-term treatment, respectively. Before therapy, all patients showed'a non-sufficient GH suppression after oral glucose load (>2 \g=m\g/l), whereas under dopaminergic treatment the post-glucose GH levels of three patients fell below 2 \g=m\g/l; normal IGF-I concentrations were found in five patients. However, under bromocriptine, only two patients showed GH suppressions below 2 \g=m\g/lfollowing glucose, accompanied with normal IGF-I levels. During bromocriptine withdrawal, GH secretion at 60 min in the oral glucose tolerance test increased significantly (17.0\m=+-\15.5 vs 5.7\m=+-\5.2 \g=m\g/l;p<0.01); the mean IGF-I level rose from 2.1 \m=+-\0.8to 4.9 \ m=+-\ 2.2 kU/l (p <0.01). IGF-I was normal during bromocriptine cessation in only one patient; none of the 12 patients showed a GH suppression below 2 \g=m\g/lafter oral glucose load. Under dopaminergic treatment hyperprolactinemia could not be detected. In conclusion, bromocriptine led to a stable suppression of both GH hypersecretion and\p=m-\if present\p=m-\concomitantlyelevated PRL levels. Severe side effects or a further tumor growth could not be observed. Thus, the data of the longest follow-up investigation that has so far been published indicate that effective life-long bromocriptine therapy seems to be possible in selected patients with acromegaly.Since 1974, when Liuzzi et al. observed the suppressive effect of bromocriptine on elevated GH levels in patients with acromegaly ( 1 ), this dopaminergic drug has been widely used for the treatment of GH secreting tumors (2. 3).It is not known whether the effectiveness of bromo¬ criptine treatment in acromegaly is limited by a certain duration of dopaminergic therapy. Recently, our study group reported on the effects of a two-week long bromocriptine withdrawal on body composition and clinical well-being in dopaminergic long-term treated acromegaly patients (4). Now, based on the same study, an evaluation is presented referring to the effectiveness of long-term bromocriptine treatment (15.0 ±6.8 mg/ day for 12 ± 3 years) and a following bromocriptine withdrawal for two weeks in 12 patients with acro¬ megaly on GH and PRL secretion.Our main interest concerned the possibility of a stable suppression of both GH hypersécrétion and-if pres¬ ent-concomitant elevated PRL levels under dopami¬ nergic treatment over a mean period of 12 years. Possible changes in tumor size would be investigated during bromocriptine long-term treatment and we wanted to determine any predictive factors for a success¬ ful outcome of b...

Bromocriptine treatment over 12 years in acromegaly: effect on glucose tolerance and insulin secretion

“…Therefore, the frequent imp r o v e m e n t in glucose tolerance and the significant reduction in hyperinsulinism in m o s t of the acromegaly patients b o t h under short-term b r o m o c r i ptine treatment [22] and under long-term d o p a m i nergic therapy m a y not be referred only to the suppression of pathologically elevated G H levels but also to the dopaminergic inhibition of P R L secretion. However, this hypothesis could not be confirmed by our findings since the five initially hyperprolactinemic patients (1,7,9,11,12) did not reveal a tendency to an especially elevated insulin secretion (the data on individual P R L secretion patterns of the 12 acromegaly patients participating in the present study has recently been published [16]). …”

“…Recently, our study group reported on the effects of a 2-week bromocriptine withdrawal on GH and prolactin (PRL) secretion in 12 patients with acromegaly receiving long-term dopaminergic treatment [16]. Based on the same study, we present here an evaluation of both the effectiveness of long-term bromocriptine treatment (15.0 + 6.8 mg/day for 12_+ 3 years) and a subsequent drug withdrawal on glucose tolerance and insulin secretion.…”

“…The reduction in b o t h fasting and stimulated blood glucose and insulin levels m a y be traced to the bromocriptine-induced stable suppression of h y p e r s o m a t o t r o p i s m [16]. C o m p a r e d with the published rates on i m p r o v e d glucose homeostasis under octreotide [14,18,20], the effect of b r o m o c r i p t i n e seems to be m o r e favorable [6].…”

82-j�hrige Patientin mit Hyperostosis frontalis, Prognathie, Makroglossie und Cutis gyrata

“…An therapeutischen Optionen bestehen die transsphenoidale Resektion sowie die medikamentöse Therapie mit Dopaminagonisten [3,10,13,15] und Somatostatinanaloga [4]. Eine Kombination der beiden medikamentösen Prinzipien kann ebenfalls erwogen werden [5,9,11,14]. Bei Versagen dieser Optionen steht inzwischen die Gabe eines GH-Rezeptorantagonisten (Pegvisomant) zur Verfügung.…”

“…Bei einzelnen Patienten, die keine Injektionen wollen oder bei denen nur ein moderater Anstieg von GH <10 ng/ ml vorliegt, können auch langwirksame Dopaminagonisten wie z. B. Cabergolin versucht werden [14]. …”