Lipid profile, glucose tolerance and insulin sensitivity after more than four years of growth hormone therapy in non-growth hormone deficient adolescents

OBJECTIVE To study the effects of long-term (>4 years) growth hormone (GH) therapy on insulin sensitivity, glucose tolerance and lipid profile in non- GH deficient adolescents at completion of their growth, SUBJECTS Thirty non-GH deficient (15 'idiopathic' short stature, 8 intraute rine growth retardation, 7 partial GH deficiency in childhood but normal on retesting) were recruited, median (range) age 16.9 years (15-20.3) prior t o ceasing their GH therapy, Their median (range) duration of GH treatment w as 7.9 years (4-11), insulin sensitivity was also recorded in 10 normal con trols with a median (range) age of 20.5 years (18.4-22.3). METHODS Insulin sensitivity was assessed by a short insulin tolerance test in 18 patients on GH therapy and controls, It was repeated in 14 patients s ix months after stopping their GH therapy, A 3-h standard oral glucose tole rance test (OGTT) was performed in 19 patients on GH therapy, and repeated after 6 months off GH in 10 patients, Fasting lipids were also measured. RE SULTS Insulin sensitivity index was significantly lower in the patients on GH therapy than in the controls, (median (range)) 3.7%/min (1.2-5.3) and 5. 3%/min (3.8-6.2), respectively. Six months after termination of GH therapy, insulin sensitivity increased significantly from 3.6%/min (1.2-5) to 4.8%/ min (2.8-5.6). Fasting plasma insulin decreased significantly off GH therap y from 10.1 to 3.6 mU/I. The area under the insulin curve during the OGTT w as also significantly higher on GH therapy, Apart from one patient with imp aired glucose tolerance on on treatment, plasma glucose concentrations rema ined within the normal range. No lipid abnormalities were recorded, CONCLUSIONS These data suggest that long-term GH therapy may cause insulin resistance in non GH deficient adolescents, but usually with neither impair ed glucose tolerance nor hyperlipidaemia.