Long-lasting lowering of serum growth hormone and prolactin levels by single and repetitive cabergoline administration in dopamine-responsive acromegalic patients.
Cabergoline, the new long-acting dopaminergic ergoline derivative, was given orally in single doses of 0.3 and 0.6 mg to eight dopamine-responsive acromegalic patients. Serum GH and PRL levels were determined before treatment, 3, 4, and 6 h and 1, 3, 5, 7 and 14 days after treatment. A control test with a single oral dose of 2.5 mg of bromocriptine was also performed. Cabergoline induced a marked fall in serum PRL level, starting within 3 h and continuing for 7 days after administering 0.3 mg, and for 14 days after 0.6 mg. The mean maximal decrease was 49% after 0.3 mg and 63% after 0.6 mg and occurred after 24 h in both cases. The latter was of similar magnitude to that induced by bromocriptine (67% at 4 h). Serum GH levels did not change after 0.3 mg of cabergoline, but decreased significantly from 3 h to 3 days after 0.6 mg of the compound with a mean maximal decrease of 42% after 24 h, and from 3 to 6 h after giving bromocriptine (mean maximal decrease 63% at 4 h). Once a week repeated administration of 0.3-0.6 mg of cabergoline was carried out in six patients, five of whom had completed the acute study; a normalization of serum GH and insulin-like growth factor I (IGF-I) levels occurred in three patients, one of whom had very high pretreatment values. In three poorly or nonresponsive patients, a better response, as assessed by both GH and IGF-I levels, was induced by increasing the dose up to 0.6 mg twice or 0.4 mg three times a week; in one case this was associated with marked tumour shrinkage. Sustained normalization of PRL levels was achieved in all cases. These data indicate that a single dose of 0.6 mg of cabergoline inhibits GH as well as PRL secretion in dopamine-responsive acromegalic patients and suggests that doses of 0.3-0.6 mg once to three times a week may prove suitable for treatment of this condition.
Ferrari
C
C
Servizio di Endocrinologia, II Divisione Medica, Ospedale Fatebenefratelli, Milano, Italy.
Paracchi
A
A
Romano
C
C
Gerevini
G
G
Boghen
M
M
Barreca
A
A
Fortini
P
P
Dubini
A
A
D000172:Acromegaly / Q000097:blood* / Q000188:drug therapy; D000328:Adult; D000818:Animals; D000077465:Cabergoline; D002642:Chick Embryo; D004298:Dopamine / Q000627:therapeutic use; D015259:Dopamine Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004873:Ergolines / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011388:Prolactin / Q000097:blood*
D015259:Dopamine Agents; D004873:Ergolines; D007334:Insulin-Like Growth Factor I; D011388:Prolactin; D013006:Growth Hormone; D000077465:Cabergoline; D004298:Dopamine