Until the last decade most physicians considered growth hormone (GH) to have no biological relevance following the cessation of linear growth. The first evidence that GH is important throughout adult life came from a report, in which a 35-year-old hypopitu-itary adult described increased vigor, ambition, and well-being, following GH replacement (1). Recombinant technology resulting in a limitless supply of GH has prompted intensive investigation of the effects of GH in health and disease, and the effects of GH replacement in adults with GH-deficiency has received particular attention.
These studies have led to the identification of a specific constellation of symptoms, signs and investigative findings, which is now recognized as the 'GH-deficiency syndrome'. The main features of the syndrome are listed in Table 1. Subsequent studies have addressed the effects of GH replacement on these features, in the form of both randomized placebo-controlled trials, and smaller open studies. These studies have produced consistent results, demonstrating that adults with GH-deficiency are both psychologi-
From: Human Growth Hormone: Research and Clinical Practice Edited by: R. G. Smith and M. O. Thorner © Humana Press Inc., Totowa, NJ
The Clinical Features of GH-Deficiency in Adults
Known pituitary pathology ± previous treatment Full 'conventional' pituitary hormone replacement Need for GH treatment as a child Symptoms
Abnormal body composition reduced lean body mass increased abdominal adiposity Reduced strength and exercise capacity Impaired psychological well-being depressed mood reduced vitality and energy emotional lability impaired self-control anxiety increased social isolation
Overweight, with predominantly central (abdominal) adiposity Thin, dry skin; cool peripheries; poor venous access Reduced muscle strength Reduction exercise performance Depressed affect, labile emotions Investigations
Stimulated GH level below 3 ^g/L
Low or low-normal serum IGF-I
Elevated serum lipids, particularly LDL cholesterol
Reduced lean body mass / increased fat mass
Reduced bone mineral density cally and physically less healthy than their age-matched peers, and that GH replacement results in substantial and sustained benefits. This chapter details the important features resulting from GH-deficiency and summarizes the effects of GH treatment, assessing the rationale for GH replacement in adults with GH-deficiency.
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