Exercise-Induced Lipolysis in Patients with Central Cushing's Disease

Abstract

The hormonal regulation of exercise-induced lipolysis was investigated in patients with a central Cushing's syndrome compared to a healthy control group. Ten of these patients were adrenalectomized and four of them additionally hypophysectomized after having developed a Nelson's tumor. Blood was taken at rest, after a moderate long-term test of 20 min at a work load of 70% V̇O₂max, and 30 and 60 min after work.

The hormone levels of epinephrine and norepinephrine, cortisol, HGH (human growth hormone), insulin, and ACTH (adrenocorticotropic hormone) were determined while the substrates FFA (free fatty acids), (β-OHB (β-hydroxybutyrate), AcAc (acetoacetate), glycerol, and lactate were also measured.

The subjects' anaerobic thresholds were determined during a maximal ergometer test.

The main findings were that in the patients exercise-induced lipolysis was accompanied by only basal epinephrine levels throughout the test and high ACTH levels that could be related to high FFA and glycerol values both at rest and after exercise. The results suggest that adrenal medullary stimulation of lipolysis during exercise is replaced by ACTH and synaptic norepinephrine impulses.

Key Words

exercise-induced lipolysis - hormonal regulation - adrenalectomy - hypophysectomy