Abstract
The effects of growth hormone (GH) treatment on 24-h energy expenditure (EE) were studied in a open trial over a period of 4 weeks. Five subjects, four men and one woman, with a history of complete GH deficiency were included. All the subjects were examined on 2 consecutive days on baseline and, thereafter, at six occasions during a period of 1 month (days 1, 2, 5, 8, 15, and 30). The dose of GH was 0.25 U/kg·week, administered sc once a day in the evening.
EE was determined in a chamber for indirect calorimetry. Body composition was determined with dual-energy x-ray absorptiometry and computed tomography using a four-scan technique. Blood samples were examined using well-established RIAs.
During the first 2 weeks, 24-h EE increased by 6 ± 3% (range 1–8%) from 40.9 ± 4.8 to 42.9 ± 4.8 kcal/24 h·kg (P < 0.05), sleeping metabolic rate by 14 ± 3% (range 10–18%) from 28.4 ± 1.9 to 32.9 ± 2.2 kcal/24h·kg (P < 0.001), and basal metabolic rate by 11 ± 7% (range 0–18%) from 29.6 ± 2.4 to 33.3 ± 2.6 kcal/24h·kg (P < 0.05). No change was found in daytime EE. The increase in EE covaried with changes in insulin-like growth factor 1, the free T3/free T4 ratio, insulin-like growth factor-binding protein-3, and the aminoterminal procollagen III peptide but not with changes in body composition.
It is suggested that the stimulating effect of GH on EE occurs gradually during a 2-week period and is only detectable during night and morning hours, when significant levels of GH occur.
Changes in body composition of human immunodeficiency virus-infected males receiving insulin-like growth factor I and growth hormone.
