Endothelial dysfunction in hypopituitary adults with growth hormone deficiency

OBJECTIVES Adult hypopituitarism with growth hormone deficiency (GHD) results in reduced exercise capacity, detrimental changes in body composition and lipid profiles and may be associated with an excess cardiovascular mortality. Endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and predisposes to the deposition of unstable atherosclerotic plaques. We have used a noninvasive method to assess endothelial function in the brachial arteries of a group of treated hypopituitary adults with GHD, and a group of healthy age‐and sex‐matched controls. PATIENTS Seventeen hypopituitary adults with GHD (13 male, 4 female) aged 26–54 years were studied. Each patient was receiving standard replacement therapy for all other hormonal deficiencies such that all target hormones were maintained in the normal reference range. All observations obtained were compared with those made in age‐ and sex‐matched control subjects. All study subjects had no identifiable risk factors for endothelial dysfunction. MEASUREMENTS Using an ultrasound vessel wall tracking system, the diameter of the left brachial artery was measured at rest, in response to reactive hyperaemia (endothelium‐dependent dilation) and following sublingual glyceryl trinitrate (GTN) (endothelium‐independent vasodilatation). We also measured fasting lipids, insulin, plasma glucose, glycated haemoglobin (HbA1c) and IGF‐1, and studied the relationship of these parameters to endothelial function. RESULTS Flow mediated endothelium‐dependent dilatation (FMD), expressed as a percentage change from resting base‐line diameter, was significantly impaired in the GHD group (3.70 ± 2.36% vs. 7.30 ± 2.42%, P