Discontinuation Of Growth Hormone Treatment Research Articles

Impact of discontinuation of growth hormone treatment on lipids and weight status in adolescents.

While the main role of growth hormone (GH) replacement therapy in children is to promote linear growth, GH has also an effect on lipids and body composition. There is an ongoing discussion whether discontinuation of GH treatment is associated with deterioration of lipids. We analyzed weight status [as body mass index-standard deviation score (BMI-SDS)], insulin like growth factor (IGF)-1, triglycerides, total, low-density liporptoein (LDL)- and high-density lipoprotein (HDL)-cholesterol at the end of GH treatment and in mean 6 months later in 90 adolescents (53 with GH deficiency, 16 with Turner syndrome [TS] and 21 born small-for-gestational age [SGA]). After stopping GH treatment, total cholesterol (+10±24 mg/dL vs. -4±13 mg/dL) and LDL-cholesterol (+15±20 mg/dL vs. -6±12 mg/dL) increased significantly higher in severe (defined by GH peak in stimulation test <3 ng/mL) compared to moderate GHD. In patients with TS, total cholesterol (+19±9 mg/dL), LDL-cholesterol (+9±12 mg/dL) and HDL-cholesterol (+4.3±3.5 mg/dL) increased significantly. In adolescents born SGA, triglycerides increased (+34±51 mg/dL) and HDL-cholesterol decreased significantly (-3.8±7.1 mg/dL). In multiple linear regression analyses, changes of total and LDL-cholesterol were significantly negatively related to peak GH in stimulation tests, but not to gender, age at GH start, duration of GH treatment, observation time, changes of BMI-SDS or IGF-1 after the end of GH treatment. The BMI-SDS did not change after the end of GH treatment. Discontinuation of GH treatment leads to a deterioration of lipids in TS, SGA and severe but not moderate GHD.

Growth Hormone Replacement in Patients with PHACE Association and Hypopituitarism

Partially empty sella with growth hormone (GH) deficiency is rarely reported in association with PHACE (posterior fossa anomalies, cervicofacial infantile hemangiomas [IHs], arterial anomalies, cardiac defects, eye anomalies, and midline/ventral defects). Consequently, little is known about the effect of GH replacement on the proliferation and involution of IHs in children with PHACE. We describe two children with PHACE and partially empty sella, both of whom received GH replacement for treatment of hypopituitarism. In our first patient we observed erythema and prominence of the vasculature in the hemangioma shortly after initiation of therapy at age 20 months, although after 4 weeks of treatment the appearance of the hemangioma stabilized and little change was seen during eight additional years of therapy. In our second patient we noted enlargement of the hemangioma after starting low-dose GH at age 5 years, prompting discontinuation of GH replacement after 3 months of therapy. The hemangiomas continued to grow after discontinuation of GH treatment. GH administration in our patients was associated with erythema and prominence of IHs. Our findings suggest that GH replacement therapy may promote transient or more prolonged proliferation of IHs and should be administered with close clinical monitoring.

Condução do tratamento com hormônio de crescimento (GH) nos pacientes com diagnóstico de deficiência GH (DGH) durante o período de transição da criança para o adulto

Growth hormone (GH) has many beneficial effects in patients with childhood-onset GH deficiency (GHD) in addition to its promotion of linear growth. The discontinuation of GH treatment in GHD patients, during the transition from childhood to adulthood, induces significant unfavorable changes in body composition, skeletal integrity, exercise capacity, and an adverse cardiovascular risk profile. These changes are reversed after the resumption of GH treatment. As the benefits of continuing GH therapy into adulthood has been well established, it is possible that GH replacement therapy will not be stopped once growth has been completed, but it will continue into adult life. Considering that a high proportion of patients with diagnosis of DGH in childhood are no longer GHD in adolescence, the GH status must be retested when growth is completed. Other factors such as clinical history, GH response in childhood, hipotalamic-pituitary MRI and IGF-1 concentration must be considered. Reconfirmation of GHD diagnosis through stimulation testing is usually required, unless there is a proven genetic or structural lesion persistent from childhood.

Growth hormone outgrows growth.

Growth hormone (GH) replacement has been offered to GH-deficient (GHD) children for approximately 40 years whereas it has only been a licensed indication for the treatment of GHD adults since 1996. Nonetheless, the advent of GH replacement for adult GHD patients (Jorgensen et al., 1989; Salomon et al., 1989) has proved informative about the overall management of the GHD child and teenager; equally, the longstanding experience of the paediatric endocrinologist with GH replacement has provided some guidance about potential pitfalls in the diagnosis and management of the adult GHD patient. It is the knowledge exchange at this professional interface that forms the focus of this article.

Growth hormone treatment in children with Noonan's syndrome: four year results of a partly controlled trial

The aim of the study was to evaluate the effect of continuous and discontinuous growth hormone treatment in Noonan's syndrome (NS) on linear growth and bone maturation. Thirty-seven children with NS aged between 5.4 and 17.5 y were treated with growth hormone (GH) in a dose of 0.15 IU kg)(-1) per day; 23 of these children were randomly assigned to one of 2 groups in a 3 y partly controlled prospective multicentre study. Group A (n = 8) immediately started GH treatment and after 2 y discontinued GH treatment for 1 y; group B (n = 15) served as a control group during the first year and started GH treatment after 1 y. After the 3 y study period, 17 out of the 23 children continued GH treatment. An additional 14 children (group C) were treated according to the same protocol, but without discontinuation of GH treatment. The effect of GH treatment for up to 3 y was evaluated in terms of gain in height standard deviation score (H-SDS) for calendar age and for bone age. Gain in H-SDS over the first year was significantly higher in the GH treatment group (+0.5) than in the non-treated group (+0.0); mean bone maturation was significantly faster in the GH treatment group (1.2 vs 0.5 y/y). Discontinuation in group A in the third study year resulted in catch-down growth (mean deltaH-SDS -0.2). Over 3 y of GH treatment, mean AH-SDS for calendar age was not significantly different between discontinuous (A: +0.8) and continuous treatment (B: +0.8; C: +1.2). Mean gain in H-SDS for bone age in the 3 groups (+0.2, 0.0. +0.3) was minimal after 3 y of GH treatment. This study confirmed the gain in H-SDS CA in Noonan's syndrome during long-term GH treatment. However, the accelerating effect of GH on bone maturation seemed to compromise the final height prognosis.

Effects of Growth Hormone Treatment on Left Ventricular Dimensions in Children with Noonan’s Syndrome

Objective: To study the effects of long-term growth hormone (GH) treatment on left ventricular (LV) dimensions in children with Noonan’s syndrome (NS). Methods: Echocardiographic measurements of LV dimensions were performed before and during GH treatment in 27 participants (21 boys, 6 girls) in a partly controlled 3-year trial of high-dose GH treatment (0.15 IU/kg/day). Nineteen children had a congenital heart defect, 1 of them had hypertrophic obstructive cardiomyopathy. In the first 3 years, the children were assigned to 1 of 2 groups: group A with discontinuation of GH treatment in the 3rd year, or group B without GH treatment in the 1st year. After the 3rd year, 12 of the 27 children were followed up for 2 additional years to evaluate the long-term effects of GH treatment on the heart. Results: At baseline, LV internal diameters were smaller, while posterior wall thickness were thicker than normal. Over the 1st year, changes in LV dimensions were comparable between the 2 groups. No significant differences were found in LV dimensions between the situation at baseline and after 4 years of GH treatment. Conclusion: Long-term high-dose GH treatment does not have clinically significant adverse effects on LV dimensions in children with NS.

Treatment of Juvenile Rheumatoid Arthritis with Growth Hormone

Severe growth retardation and profoundly altered body composition are observed in children with juvenile chronic arthritis receiving glucocorticoids. This study assessed the effects of growth hormone (GH) on height velocity, body composition and bone density. Fourteen patients were treated with GH (1.4 U/kg/week) for 1 year and then studied for a 2nd year off GH. The treatment increased insulin-like growth factor 1 and insulin-like growth factor binding protein 3 plasma levels. All patients showed an increase in height velocity. Lean body mass increased by 12%. After the cessation of GH therapy, height velocity fell to pretreatment values, and weight and fat mass increased markedly. Bone formation and resorption markers significantly increased during treatment and returned to pretreatment values after discontinuation of GH treatment. These results suggest that GH may partially counteract the adverse effects of glucocorticoids on growth and metabolism in patients with chronic inflammatory disease.

A longitudinal study on bone mineral density until adulthood in girls with Turner's syndrome participating in a growth hormone injection frequency-response trial

The aim of this study was to assess the volumetric bone mineral density (BMD) in girls with Turner's syndrome (TS) before and during growth hormone (GH) treatment in combination with low dose oestrogens as well as three years after discontinuation of GH treatment. In a prospective, randomized injection frequency-response study, the effect of GH treatment in combination with low dose ethinyl oestradiol (starting with 0.05 microgram/kg/day), on BMD was evaluated, comparing twice daily (BID) with once daily (OD) injections of a total GH dose of 6 IU/m2/day until adult height was reached. After discontinuation of GH treatment, the dosage of oestrogens was further increased to adult supplementation levels. Nineteen untreated girls with TS, mean (SD) baseline pretreatment age 13.3 (1.7) (range 11.0-17.6) year. Before and during GH treatment, measurements of volumetric BMD were performed using phalangeal radiographic absorptiometry. In addition, the BMD measurements were repeated three years after discontinuation of GH treatment. BMD results were adjusted for bone age and sex, and expressed as SD-scores (SDS) using reference values of healthy Dutch girls. At baseline, most individual BMD values of cortical bone as well as those of trabecular bone were within the normal range of healthy girls. However, the mean BMD SDS of the trabecular bone was significantly lower than zero. During treatment, the BMD SDS showed a significant increment to values equal or higher than zero after mean (SD) GH treatment period of 36.6 (7.5) months. The increase in BMD of the cortical bone was significantly higher in the OD group than in the BID group. The BMD SDS in the last year of GH treatment was not significant different between the two injection frequency groups. Three years after discontinuation of GH treatment, the BMD values had increased further similar as in healthy girls, resulting in BMD values all within normal range or even higher. Most untreated girls with Turner syndrome, age >/= 11 years, have a normal volumetric BMD of the cortical, as well as of the trabecular bone compared to healthy girls. During GH treatment with 6 IU/m2/day in combination with low dose oestrogens, the BMD SDS increases significantly. After discontinuation of GH treatment and the use of oestrogens in an adult dosage, the BMD was as high as in young healthy women.

Continuation of Growth Hormone (GH) Replacement in GH-Deficient Patients during Transition from Childhood to Adulthood: A Two-Year Placebo-Controlled Study

Previous studies have demonstrated beneficial effects of GH replacement, in adults with GH deficiency (GHD), on body composition, physical fitness, and quality of life. These studies, however, concern patients with adult-onset GHD or childhood-onset (CO) patients enrolled several years after withdrawal of initial therapy. So far, the effects of continuation of GH-administration in patients with CO-GHD have not been examined. We studied a group of nineteen young adults (13 males+ 6 females; 16–26 yr old; mean age, 20.2 ± 0.65 yr) with CO-GHD, in a randomized, parallel, double-blind, placebo-controlled trial for 1 yr, followed by an open phase with GH for 1 yr. All patients received GH therapy at the start of study, and trial medication (GH/placebo) was given in a similar dose. Patients randomized to continued GH treatment exhibited no significant changes in any parameters tested, but intra- and interindividual variations in insulin-like growth factor (IGF)-I levels could suggest compliance problems. Discontinuation of GH for 1 yr resulted in a decrease in serum IGF-I, from 422.0 ± 56.8 to 147.8 ± 33.4 μg/L, in the placebo group (P = 0.003). After discontinuation of GH for 1 yr, an increase in total body fat (TBF, kg), measured by dual-energy x-ray absorptiometry scan, was seen[ placebo: 22.7 ± 2.7 to 26.5 ± 2.5 (P = 0.01); GH:16.2 ± 2.1 to 17.2 ± 2.1 (not significant)]. Resumption of GH after placebo was followed by increments in serum IGF-I (μg/L) [from 147.8 ± 33.4 to 452 ± 76 (P = 0.001)] and IGF-binding protein 3, as well as in fasting glucose (mmol/L) [4.9 ± 0.2 vs. 5.3 ± 0.2 (P = 0.03)]. After resumption of GH lean body mass (kg) increased [52.4 ± 4.9 vs. 60.7 ± 5.6 (P = 0.006)]. Likewise, resumption of GH therapy increased thigh muscle volume and thigh muscle/fat ratio, as assessed by computed tomography [muscle volume (cm2/10 mm): 118.2 ± 11.7 vs. 130.0 ± 10.9 (P = 0.002); muscle/fat ratio: 1.33 ± 0.24 vs. 1.69 ± 0.36 (P = 0.02)]. In conclusion, discontinuation of GH treatment in GHD patients, during the transition from childhood to adulthood, induces significant and potentially unfavorable changes in IGF-I and body composition, both of which are reversed after resumption of GH treatment. By contrast, continuation of GH therapy results in unaltered IGF-I and body composition. We recommend continuation of GH therapy in these patients, to be undertaken in collaboration between pediatricians and adult endocrinologists.

Carbohydrate Metabolism during Long-Term Growth Hormone (GH) Treatment and after Discontinuation of GH Treatment in Girls with Turner Syndrome Participating in a Randomized Dose-Response Study

Carbohydrate Metabolism during Long-Term Growth Hormone (GH) Treatment and after Discontinuation of GH Treatment in Girls with Turner Syndrome Participating in a Randomized Dose-Response Study

Effects of Discontinuation of Growth Hormone Treatment on Body Composition and Metabolism

This study was directed to the investigation of two different aspects of growth hormone: What are the metabolic consequences following the discontinuation of treatment and are these metabolic effects correlated with the growth-promoting effects seen in the first year of treatment? The study was performed on 12 growth hormone-deficient (GHD) patients who reached their final height. Each patient was matched with a non-GHD person of the same sex and about the same age. Immediately after the discontinuation of treatment, and 6 weeks and 6 months later, the following anthropometric variables were assessed: height, weight, skinfold thicknesses (biceps, triceps, subscapular and suprailiacal), body volume (underwater weighing) and total body water (deuterium dilution). To describe energy metabolism, basal metabolic rate assessed by ventilated hood, and sleep metabolic rate assessed by respiration chamber, were studied. Body composition was calculated from weight, volume and total body water. Clear metabolic effects were found after the discontinuation of treatment in GHD children: there was a decrease in fat free mass and sleep metabolic rate. Also, a strong correlation between the above-mentioned effects and the growth-promoting effects of human growth hormone at the beginning of the treatment was observed. The fact that this correlation exists poses the interesting question of whether the results from a test treatment lasting some weeks could be used to predict the long-term effects of hGH.

Final Height in Girls with Turner Syndrome after Growth Hormone Treatment. Experience at National Children's Hospital.

Twenty-four patients with Turner syndrome were treated with human growth hormone (GH) and reached their final height. Mean age was 11.7 years and mean height SDS was 0.28 SD for Japanese Turner standard at the start of GH treatment. Mean duration of GH treatment was 6.6 years and mean age at discontinuation of GH treatment was 18.6 years. Final height of all the patients was 146.9 ± 4.2 cm (140.5∼153.9 cm). Since predicted adult height (PAH) was 139.4 ± 5.8 cm (131.8∼155.0 cm), the benefit from growth-promoting therapy (final height - PAH) was 7.5 ± 4.6 cm (-1.4∼+15.2 cm). The final height in 10 patients (42%) exceeded the -2.0 SD value (147.9 cm) for normal girls. It can be concluded that the adult height in Turner syndrome was improved by GH treatment. However, final height was improved by starting pubertal induction later in addition to GH treatment in Japan. Early diagnosis and initiation of treatment with a higher dose of GH is important for adequate pubertal induction and final height.

Metabolic effects of discontinuing growth hormone treatment.

To evaluate the effects of discontinuing growth hormone (GH) treatment on energy expenditure and body composition, which might help predict those most likely to benefit from early reintroduction of GH treatment in young adult life. Body composition was calculated from skinfold thicknesses and dual energy x ray absorptometry (DXA). Resting metabolic rate (RMR) and whole body bone mineral content (BMC) were also measured. Measurements were made before stopping treatment, at discontinuation of GH treatment, and two weeks, six months, and one year later in 11 adolescents with growth hormone deficiency (GHD) and five adolescents without GHD who were treated with GH. Measurements were compared with 10 healthy controls, in whom measurements were repeated one year later. During the nine months before discontinuation of GH there were no changes in body composition, RMR, or BMC of patients with GHD, nor differences when compared with controls. RMR was reduced by 11.3 kJ/kg fat free mass two weeks after stopping GH in GHD patients and remained suppressed thereafter compared with controls. Percentage body fat increased by 4.3%/year in patients with GHD after discontinuing GH, whereas no changes were noted in control or non-GHD patients at one year. The patients experiencing the greatest reductions in RMR/kg fat free mass at six months showed the largest increases in body fat at one year. No change in BMC was noted in patients one year after stopping treatment. Important metabolic changes occur early after discontinuing GH treatment. In patients whose growth is complete, these changes might be used to predict those most likely to benefit from continuation of GH treatment into adult life.

Long-term prospective study of body composition and lipid profiles during and after growth hormone (GH) treatment in children with GH deficiency: gender-specific metabolic effects.

GH has many effects on metabolism in addition to promoting growth. We studied changes in body composition and lipid profiles during and after GH treatment in 94 children with GH deficiency. Sixty-two subjects (46 boys and 16 girls) were evaluated at the beginning and during 36 months of GH treatment. The other 32 (21 boys and 11 girls) who had already been treated with GH were examined after the discontinuation of GH for a 6-month period. The height SD scores at the beginning and the discontinuation of GH treatment were -2.81 and -1.34 in boys and -3.14 and -1.38 in girls, respectively. The percent body fat (BF) significantly decreased from 16.5% to 11.7% in boys and from 16.7% to 11.6% in girls during the first 6 months of GH treatment (P < 0.01). BF subsequently remained constant in boys, but started to increase in girls from the 18th month of treatment. Lean body mass (kilograms) increased linearly throughout the treatment in both sexes (P < 0.01). Mean total cholesterol (TC) values decreased as a result of marked declines in low density lipoprotein cholesterol in both sexes, although statistical significance was detected only in boys (P < 0.01). High density lipoprotein cholesterol (HDLC) and apolipoprotein AI (Apo-AI) rapidly increased only in boys (P < 0.01). Triglyceride, Apo-AII, Apo-B, Apo-CII, Apo-CIII, Apo-E, and lipoprotein(a) showed no significant changes compared with baseline levels. Mean TC/HDLC and Apo-B/Apo-AI ratios decreased during treatment in both sexes, but the difference from baseline was significant only in boys (P < 0.01). After discontinuation of GH treatment, BF increased, and lean body mass decreased in boys (P < 0.01), whereas these variables did not change in girls. TC and low density lipoprotein cholesterol increased in boys within 6 months of discontinuing GH (P < 0.05). Other lipoproteins did not change in either sex, except for lipoprotein(a), which decreased significantly 6 months after the cessation of GH treatment in boys (P < 0.01). The mean TC/HDLC and Apo-B/Apo-AI ratios increased in boys slightly, but insignificantly. We concluded that GH treatment has beneficial effects on body composition and lipid profiles in both boys and girls with GH deficiency, although there are considerable gender differences. These beneficial effects of GH were reversed after the discontinuation of GH treatment, suggesting an important role of GH for GH-deficient children in the maintenance of normal metabolism even after the completion of linear growth.

Impaired reproductive function in women treated for growth hormone deficiency during childhood.

There are limited data which suggest that disturbance of reproductive function may occur in GH-deficient women. We have evaluated the consequences of growth hormone (GH) deficiency on reproductive function in women treated for GH deficiency during childhood. Questionnaires were sent to 73 GH-deficient women who had been treated for GH deficiency during childhood. The response rate was 82%. These 60 women were then visited to obtain further information concerning their reproductive status. During these visits, blood samples were obtained from 39 women, to evaluate their hormonal status, and 29 of them had a standard insulin tolerance test (ITT), as part of an adult GH substitution trial. Paediatric and gynaecological records were evaluated in all 60 women. Sixty GH-deficient women treated in childhood for this deficiency were included in the study. The median age at follow up was 27 years (range 20-43). GH treatment had been discontinued for 9 years (range 2-26). In the questionnaire and during the visit, attention was paid to GH treatment, pubertal development, menstrual cycle disturbances and fertility. In the 39 blood samples IGF-1, IGFBP-3, TSH, T4 and T3 were measured. GH responses were measured by a standard ITT. Thirty-four women showed no spontaneous pubertal development. Of the 26 women who did, menarche occurred in 39% at the age of 16 years or older. At the time of the study, menstrual cycles in these 26 women were as follows: 12 had regular menstrual cycles, three had developed secondary amenorrhoea after discontinuation of GH treatment, five had irregular menstrual cycles and six had oligomenorrhoea. The 34 women with disturbed pubertal development and the three with secondary amenorrhoea were infertile because of hypogonadotrophism. Only 13 out of 60 women desired pregnancy or had been pregnant. Three with regular menstrual cycles had primary infertility. Ten had ovulation induced or IVF. Six of these became pregnant after 1-7 cycles. Three were still under treatment, the duration of their treatment varying from 3 to 7 years. One woman discontinued treatment. At the time of the study, nine women had actually conceived. Five out of ten completed pregnancies resulted in Caesarian sections because of cephalo-pelvic disproportion or arrest of labour. During the ITT three of 29 women showed GH responses exceeding 5 micrograms/l (10 mU/l), ruling out complete GH deficiency. Higher GH peaks (NS), IGF-1 (P , 0.01) and IGFBP-3 (P < 0.01) levels were found in women with regular menstrual cycles, compared to women using sex-steroid substitution and amenorrhoeic women. From this study, it can be concluded that disturbances in reproductive function can be expected in women treated for GH deficiency during childhood, so it is advisable to inform these women of this possibility and to maintain follow-up after discontinuation of GH treatment. Whether the somatotrophic axis exerts a direct effect on ovarian function or whether more severe GH deficiency is more frequently accompanied by disturbances in gonadotrophin secretion still has to be elucidated.

Effects of human growth hormone in critically ill nonseptic patients

To study the effects of growth hormone administration on insulin-like growth factor I concentration, nitrogen balance, and fuel utilization, and to study its safety in critically ill nonseptic patients. Prospective, randomized, placebo-controlled trial. Medical intensive care unit of a university hospital. Eighteen critically ill nonseptic patients were studied for 8 days after admission. Growth hormone (0.1 mg/kg/day) or placebo was administered as a continuous intravenous infusion on the second, third, and fourth days after admission. The study period was 8 days. Plasma hormone concentrations were measured every 6 hrs and average daily values were calculated. The 24-hr urinary nitrogen and 3-methylhistidine excretion were measured. Indirect calorimetry was used to calculate fuel utilization. Insulin-like growth factor I concentrations increased in the treatment group from subnormal to normal values and remained increased despite discontinuation of growth hormone treatment (p = .02). Nitrogen balance differed between the groups upon admission: growth hormone group (3.9 +/- 4.1 g/day) vs. controls (13.8 +/- 5.4 g/day), but improved with growth hormone. This finding appeared independent of the imbalance between the groups. The 3-methylhistidine excretion was not different between the groups and did not change during growth hormone administration. Free fatty acids and glycerol concentrations increased during growth hormone treatment, but calculated fuel utilization did not change. During growth hormone treatment, insulin concentrations increased, due to the increased administration of insulin necessary for glycemic control. Side effects other than hyperglycemia were not observed. Growth hormone administration in a heterogeneous group of critically ill nonseptic patients resulted in normalization of insulin-like growth factor I levels, even after cessation of growth hormone treatment. Nitrogen balance improved, but this change was transient. Hence, growth hormone affects nitrogen balance, probably partly independent of insulin-like growth factor I.

Changes in skeletal muscle and body composition after discontinuation of growth hormone treatment in growth hormone deficient young adults*

The aim of this study was to determine whether there are any changes in skeletal muscle strength and size and body composition following growth hormone (GH) withdrawal in GH deficient young adults. A longitudinal, 1-year, open, uncontrolled study of the changes in skeletal muscle and body composition following GH withdrawal was performed. Endocrine status was reassessed at the end of the study period during an insulin tolerance test. Some measurements were repeated after 2 years of treatment. Twelve (11 male, one female; age range 14-21) patients who had been diagnosed during childhood as growth hormone deficient took part in the study. Four of the 12 patients were found to have a normal GH response on retesting at the end of the study and their results were analysed as a separate group. Quadriceps and forearm flexor maximum voluntary isometric strength, body fat content and serum IGF-1 were measured at 3-monthly intervals over 1 year. Every 6 months muscle size was measured from computerized tomography scans and fibre area from quadriceps needle biopsy samples. For the growth hormone deficient group the 12 month quadriceps strength, size and fibre areas were 94.0% +/- 8.5 (mean +/- SD), 94.5% +/- 6.3 and 85.6% +/- 17.7 respectively of control (baseline) values. Forearm flexor strength and size were 101.4% +/- 7.9 and 92.0% +/- 9.2 of control. Body fat percentage had increased from 19.5% +/- 8.6 to 24.1% +/- 9.5. No change was seen in the non-growth hormone deficient group. Although the changes measured were relatively small they suggest a role for GH in the maintenance of muscle integrity and body composition in the young adult with growth hormone deficiency.

Changes in skeletal muscle after discontinuation of growth hormone treatment in young adults with hypopituitarism.

Skeletal muscle strength and size were measured for 1 year following discontinuation of human growth hormone (hGH) treatment in 11 patients with hypopituitarism. Quadriceps and forearm flexor maximum voluntary isometric strength and size were measured. At the end of the study, endocrine status was reassessed by an insulin tolerance test. Three of the 11 subjects were found to have normal hGH secretion and were not included in the analysis. At 12 months, quadriceps strength, size and fibre areas were 94.0 +/- 8.5%, 94.5 +/- 6.3% and 85.6 +/- 17.7% (mean +/- SD), respectively, of baseline values. Forearm flexor strength and size were 101.4 +/- 7.9% and 92 +/- 9.2% of control values. Although these changes are relatively small, they suggest a role for growth hormone in the maintenance of muscle in the adult.