Effect of bromocriptine withdrawal in acromegaly on body composition as assessed by bioelectrical impedance analysis.
To evaluate the effect of bromocriptine withdrawal after dopaminergic long-term treatment (15.0 +/- 6.8 mg/day, mean +/- SD) in 12 acromegalic patients on body composition, bioelectrical impedance was measured before and at the end of two weeks of drug withdrawal. During withdrawal basal hGH and IGF-I increased from 2.5 +/- 1.9 micrograms/l and 2.1 +/- 0.8 kU/l to 9.1 +/- 11.7 micrograms/l and 4.9 +/- 2.2 kU/l, respectively, and the hGH secretion deteriorated significantly both after oral glucose load and in the TRH test, indicating recurrence of active acromegaly. Reactance and resistance decreased by 5 +/- 4 and 23 +/- 19 omega, respectively (p less than 0.01), whereas body weight remained constant (+0.4 +/- 2.1 kg). Bioelectrical impedance analysis indicated evident shifts in body composition, i.e. a significant reduction of body fat (-2.0 +/- 1.7 kg) and a simultaneous increase in both lean body mass (+2.4 +/- 2.2 kg) and total body water (+1.8 +/- 1.6 l). The changes in body composition were related to a combined effect of unsuppressed hypersomatotropism and the lack of bromocriptine actions other than inhibition of hGH secretion (for example stimulation of the renin-angiotensin-aldosterone system by both the recurred hypersomatotropism and the absence of dopaminergic bromocriptine effects). We conclude that bioelectrical impedance analysis is a good additional tool to assess the pathophysiological effects of bromocriptine withdrawal in long-term treated acromegalic patients.
Rau
H
H
Abteilung für Endokrinologie, Johann Wolfgang Goethe-Universität, Frankfurt, Germany.
Fischer
H
H
Schmidt
K
K
Lembcke
B
B
Althoff
P H
PH
D000172:Acromegaly / Q000188:drug therapy*; D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water; D001835:Body Weight / Q000187:drug effects; D001971:Bromocriptine / Q000494:pharmacology*; D002675:Child, Preschool; D004594:Electrophysiology; D005260:Female; D013006:Growth Hormone / Q000096:biosynthesis; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis; D008297:Male; D010992:Plethysmography, Impedance; D013375:Substance Withdrawal Syndrome
D001786:Blood Glucose; D001971:Bromocriptine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone