Effect of octreotide on 24-hour growth hormone and prolactin secretory patterns in acromegalics.
Four adult patients with active acromegaly underwent studies of their 24-hour secretory pattern of hGH and Prl prior to and at the end of 3 months of treatment with the octreotide (somatostatin analog SMS 201-995) 100 micrograms s.c. every 8 h. Blood was withdrawn at 30-min intervals with the aid of a constant withdrawal pump. The best fit cosinor method was used to define the following rhythm parameters: mesor, amplitude, acrophase and periodicity. Prior to treatment, hGH secretion was increased in all patients. The mean 24-hour ranged from 9-47 ng/ml with amplitude 5.2-23 and observed maximal pulse 41-95 ng/ml. Computed rhythms were circadian in 3 patients and ultradian in 1; in 2 patients the acrophases were shifted to daytime. hPrl secretion was altered in 3 of the patients. Two had elevated mean 24-hour of 17.7 and 22.2 ng/ml, while computed rhythms showed semicircadian periodicity in 1 of them and circadian periodicity with a shift of acrophase to daytime in the other. The third patient who had normal hPrl levels, showed ultradian 8-hour periodicity. At the end of treatment there was a marked reduction in hGH secretion in 1 patient and a lesser reduction in the other 3. The rhythm was influenced by the masking effect of the drug, to yield an 8-hour period with acrophases related to injection clock time having equal amplitudes.(ABSTRACT TRUNCATED AT 250 WORDS)
Schindel
B
B
Institute of Pediatric and Adolescent Endocrinology, Beilinson Medical Center, Tel Aviv University, Israel.
Ashkenazi
I
I
Keret
R
R
Silbergeld
A
A
Wasserman
M
M
Lapidot
M
M
Harris
A G
AG
Laron
Z
Z
D000172:Acromegaly / Q000188:drug therapy* / Q000503:physiopathology; D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000008:administration & dosage / Q000627:therapeutic use*; D011388:Prolactin / Q000378:metabolism
D011388:Prolactin; D013006:Growth Hormone; D015282:Octreotide