High affinity growth hormone binding protein in plasma of patients with acromegaly and the effect of octreotide treatment.
OBJECTIVE
The objective of this study was to investigate the effect of plasma GH-levels on the high affinity growth hormone binding protein (GHBP).


METHODS
We studied plasma samples of eight patients with acromegaly and eight age and sex matched healthy subjects.


METHODS
Patients with acromegaly were treated with octreotide administered by continuous subcutaneous infusion. Levels of growth hormone binding protein (GHBP) were measured in plasma samples before therapy and 3, 6 and 12 months after starting treatment. During this period, octreotide was administered in doses of 300-800 micrograms/day. The mean dose per patient over the study period ranged from 300 to 575 micrograms/24 h. The GHBP levels of patients with acromegaly were compared with those in the healthy subjects.


METHODS
Bound and free 125I-GH in plasma were measured using FPLC gel chromatography on a Superose 12 column, after an overnight incubation period. The binding data were used for a Scatchard plot analysis. Wilcoxon's signed rank test was used for statistical analysis.


RESULTS
We found lower GHBP levels in acromegalic patients (P = 0.01) than in the control subjects. Octreotide treatment resulted in IGF-I levels < 300 micrograms/l in four patients. In these patients GHBP levels increased.


CONCLUSIONS
We conclude that growth hormone binding protein levels are down regulated in acromegaly, indicating an important role for GH in the regulation of this protein.
Roelen
C A
CA
Department of Endocrinology, Academic Hospital Utrecht, The Netherlands.
Donker
G H
GH
Thijssen
J H
JH
Koppeschaar
H P
HP
Blankenstein
M A
MA
D000172:Acromegaly / Q000097:blood* / Q000188:drug therapy; D000328:Adult; D002352:Carrier Proteins / Q000097:blood*; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use*; D012189:Retrospective Studies
D002352:Carrier Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D015282:Octreotide; C051815:somatotropin-binding protein