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Increased growth hormone pulse frequency in acromegaly
A L Barkan1, S E Stred, K Reno
1Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109.
The Journal of Clinical Endocrinology and Metabolism
|December 1, 1989
Summary
Acromegaly patients exhibit increased growth hormone (GH) secretion pulses, suggesting continued stimulation by high rates of GH-releasing hormone (GHRH). This regulation persists even during somatostatin analog therapy.
Area of Science:
- Endocrinology
- Neuroendocrinology
Background:
- Acromegaly is characterized by excessive growth hormone (GH) secretion.
- The regulatory role of hypothalamic GH-releasing hormone (GHRH) in acromegaly is not fully understood.
Purpose of the Study:
- To investigate the regulatory control of GH secretion by GHRH in acromegaly.
- To compare GH secretion patterns in acromegaly patients with normal volunteers.
Main Methods:
- Studied 22 acromegaly patients and 6 healthy controls.
- Assessed pulsatile GH secretion via frequent blood sampling (10 or 20 min for 24 h).
- Measured acute GH responses to GHRH-44 and GH secretion during SMS 201-995 therapy.
Main Results:
- Acromegaly patients showed significantly higher spontaneous GH pulse frequency (12.9 pulses/24h) compared to controls (4.3 pulses/24h).
- GH pulse amplitude and acute GH responses to GHRH did not differ between groups.
- Nocturnal augmentation of GH secretion was similar in both groups and persisted during SMS 201-995 treatment.
Conclusions:
- GH secretion in acromegaly remains under stimulatory control by GHRH.
- GHRH may be released at an abnormally high rate in acromegaly patients.
- These findings highlight the persistent GHRH influence on GH secretion in acromegaly.