Preservation of Growth Hormone Pulsatility Despite Pituitary Pathology, Surgery, and Irradiation1

• Published in: The journal of clinical endocrinology and metabolism Vol. 82; no. 7; pp. 2215 - 2221
• Main Authors: Toogood, Andrew A, Nass, Ralf M, Pezzoli, Suzan S, O’Neill, Paul A, Thorner, Michael O, Shalet, Stephen M
• Format: Journal Article
• Language: English; Japanese
• Published: Endocrine Society 01-07-1997
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jcem.82.7.4103

Detailed assessment of physiological and pathophysiological GH
secretion has, until recently, been limited by the poor sensitivity of
the available assays. We have used an ultrasensitive chemiluminescence
GH assay (sensitivity, 0.002 μg/L) to study 24-h GH profiles (20-min
sampling) from 24 patients who had been treated for
hypothalamic-pituitary disease with surgery and irradiation and from 24
healthy control subjects matched for age, sex, and body mass index.
Twenty-three of the 24 patients demonstrated pulsatile GH secretion,
determined by Cluster. The median (range) area under the curve for GH,
mean pulse area, mean pulse height, average valley mean level, and mean
interpeak nadir were lower in the patients than in the controls[
119.25 (7.273–843.600) vs. 968.539 (227.200–4625.000)
min/μg·L (P < 0.00001); 3.777 (0.288–30.850)
vs. 61.390 (12.880–224.210) min/μg·L
(P < 0.00001), 0.107 (0.010–0.958) vs.
1.408 (0.368–5.050) μg/L (P < 0.00001), 0.074
(0.006–0.415) vs. 0.348 (0.048–2.350) μg/L
(P < 0.00001), and 0.066 (0.003–0.270)
vs. 0.205 (0.021–1.838) μg/L (P =
0.0004), respectively]. The median (range) number of pulses, mean
pulse duration, and mean interval between pulses did not differ between
the patients and controls [10 (4–15) vs. 10 (7–15;
P = 0.36), 96.4 (68.0–220.0) vs.
104.0 (72.0–151.4) min (P = 0.65) and 128.0
(92.8–255.0) vs. 126.2 (90.0–180.0) min
(P = 0.73), respectively]. The diurnal rhythm of
GH secretion was present in the controls, but there was only limited
evidence of residual diurnal rhythm in the patients.
This study has demonstrated that GH secretion remains pulsatile in
GH-deficient patients despite the mass effect of hypothalamic-pituitary
pathology, pituitary surgery, and radiotherapy. With the development of
potent GH secretagogues that are active orally, our findings may have
important implications for the future management of GH-deficient
subjects.