Growth Hormone Secretion after Testosterone Administration to Men with Visceral Obesity

Visceral obesity in men has been reported to be characterized by low testosterone (T) and insulin-like growth factor I (IGF-I) concentrations, the latter suggesting a relative growth hormone (GH) deficiency. Since T and GH-secretions are interrelated, men with visceral obesity were substituted with T for 14 days, and diurnal secretion pattern of GH as well as IGF-I concentrations, and metabolic variables were followed. Visceral obese men were characterized by a decreased total GH secretion and diminished peak amplitude, size, and number. T-substitution was followed by elevation of IGF-I levels. The IGF-I increase correlated with the elevation of T-concentration, and was most pronounced in men with the lowest concentrations of free T from the outset. There were no detectable changes in total quantity, amplitude, size or number of peaks of GH secretion. Glucose, chlolesterol and triglycerides as well as diastolic blood pressure decreased. There were no changes in thyroid or hematology variables. T-substitution of visceral obese men is followed by an elevation of IGF-I concentrations. It is suggested that this might be due either to minor, non-detectable increases in GH secretion, or to direct effects of T on IGF-I concentrations. The regulatory mechanisms by which T-administration are leading to metabolic and anthropometric improvements, might be direct effects of T, with or without mediation via GH secretion.

Epidemiology and long-term survival in acromegaly. A study of 166 cases diagnosed between 1955 and 1984

In 1985, a follow-up investigation was performed of all patients with acromegaly (n = 166, 89 women and 77 men) seen over a 30-year period (1955-1984) at our Endocrine Unit, referral centre for the western region of Sweden (population 1.5 million). At the end of 1984, the prevalence of the disease was 6.9 per 10(5) inhabitants, the average incidence per year was 3.3 per million people. Mean age at diagnosis was 46.3 years and at death (n = 62) 64.1 years. About one-third of the patients (50/153), in whom it had been possible to estimate the total duration of the disease, had survived for more than 25 years. Mortality was, however, increased compared to the normal population. The observed number of deaths from vascular and malignant disorders was 32 and 15, respectively, compared to the expected numbers 9.0 (p less than 0.001) and 5.6 (p less than 0.01).

Long-term corticosteroid treatment in giant cell arteritis

Ninety patients with giant cell arteritis were followed up 9-16 years (median 11.3 years) after diagnosis. The mean duration of corticosteroid therapy was 5.8 years (range 0-12.8 years). Together, the patients had received corticosteroids for 492 patient-years. Five years after diagnosis, 43% of the patients were on corticosteroid therapy. After 9 years, 15 of 60 surviving patients (25%) were still being treated with 1.25-10 mg of prednisolone daily (median dose 5 mg). The relapse rate was about 50%, regardless of the time after diagnosis, when an attempt to withdraw the treatment was made. Forty-six per cent of the relapses occurred within one month and 96% within one year of the end of treatment. Most of the flare-ups occurred during the first year of therapy and in 55% of the patients on a prednisolone dosage of 5 mg or less. We did not find any increase in morbidity in our patients compared to the general population. Nor did we see any significant complications which we could attribute to the steroid treatment.

Prognosis of giant cell arteritis including temporal arteritis and polymyalgia rheumatica. A follow-up study on ninety patients treated with corticosteroids

Ninety patients with giant cell arteritis (GCA) were followed 3-10 years after the diagnosis. The mean observation time was 63 months. Thirteen patients died. Corticosteroids were administered to all but one patient; 35 were still on treatment after a mean observation period of 59 months. In 38 patients, 94 flare-ups of the disease were recorded during corticosteroid treatment, most of them occurring during the first year of treatment and when a low dose of prednisolone had been given. Thirty-three relapses, 76% within 3 months, occurred in 28 patients after withdrawal of treatment. One patient relapsed after more than ten years of disease. Polymyalgia rheumatica was the most common symptom of flare-up or relapse, regardless of the clinical picture at the time of diagnosis. The duration of treatment should be individualized. One year of treatment is enough in a few patients, whereas others need steroid therapy for more than four years. The rate of intercurrent disease and complications of GCA or its treatment was low. No patient developed severe eye damage due to GCA. The mortality rate was in fact lower than expected with regard to age and sex.

Long-term survival in giant cell arteritis including temporal arteritis and polymyalgia rheumatica. A follow-up study of 90 patients treated with corticosteroids

Ninety patients with giant cell arteritis (GCA) were followed for 9-16 years after diagnosis. Corticosteroids were given to all but one patient. Forty-two patients died during the observation period (27 women and 15 men). The survival was compared with that in the general population and found not to be reduced among the GCA patients. In fact, we found a lower mortality than expected after five years from diagnosis (p less than 0.05). We did not see any increase in deaths due to vascular or malignant diseases in our patients.

Acute phase reactants in the initial phase of giant cell arteritis

The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen and haptoglobin were followed weekly during the initial phase of corticosteroid treatment in 18 patients with 19 episodes of giant cell arteritis (GCA). Fibrinogen and CRP decreased most rapidly, with normal values in 67% of the patients after two weeks of treatment. After two weeks 56% of the patients had normal ESR values and 76% after five weeks. Haptoglobin normalised most slowly, no patient having a normal value after one week, 29% after two weeks and 75% after six weeks. For routine clinical use, we found the ESR alone sufficient for monitoring the initial steroid treatment.

An alternate-day corticosteroid regimen in maintenance therapy of giant cell arteritis

It is well established that the side-effects of corticosteroid treatment can be reduced by administering the steroid on alternate days. Twenty-seven patients with giant cell arteritis were given daily treatment initially, followed by a gradual transition to alternate-day treatment. It was possible to maintain 18 (67%) of 27 patients on this regimen. In 9 (33%) the regimen was abandoned because of clinical symptoms on the "day off". These patient, however, could be maintained with a single morning dose of the corticosteroid. Morning plasma cortisol levels on the treatment day were normal in all patients treated with 20 mg prednisolone or less every other day.

Detection of growth hormone abuse in sport

OBJECTIVE

To develop a test for GH abuse in sport.

DESIGN

A double blind placebo controlled study of one month's GH administration to 102 healthy non-competing but trained subjects. Blood levels of nine markers of GH action were measured throughout the study and for 56 days after cessation of GH administration. Blood samples were also taken from 813 elite athletes both in and out of competition.

RESULTS

GH caused a significant change in the nine measured blood markers. Men were more sensitive to the effects of GH than women. IGF-I and N-terminal extension peptide of procollagen type III were selected to construct formulae which gave optimal discrimination between the GH and placebo groups. Adjustments were made to account for the fall in IGF-I and P-III-P with age and the altered distribution seen in elite athletes. Using a cut-off specificity of 1:10,000 these formulae would allow the detection of up to 86% of men and 60% of women abusing GH at the doses used in this study.

CONCLUSIONS

We report a methodology that will allow the detection of GH abuse. This will provide the basis of a robust and enforceable test identifying those who are already cheating and provide a deterrent to those who may be tempted to do so.

Effects of GH and insulin-like growth factor-I on body composition

In this review, different methods to estimate body composition are discussed shortly. The effects by GH on total and visceral fat mass, lean mass, muscle strength and body water are described. Gender differences in the sensitivity to GH administration are reviewed. Finally, a short description of the effects of insulin-like growth factor-I (IGF-I) administration on body composition has been included.

Increased Interleukin-6 levels in pituitary-deficient patients are independently related to their carotid intima-media thickness

OBJECTIVE

Increased cardiovascular morbidity and mortality has been observed in patients with pituitary deficiency and untreated growth hormone deficiency (GHD). We investigated peripheral inflammatory and fibrinolytic markers and their associations with arterial intima-media thickness (IMT) in GHD.

DESIGN

Cross-sectional study.

PATIENTS

Thirty-four patients with GHD, but without cardiovascular disease, were compared to healthy controls matched for age, sex, body mass index (BMI) and smoking habits.

MEASUREMENTS

IMT of the common carotid artery, C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, plasminogen activator inhibitor-1 (PAI-1) activity and tissue plasminogen activator antigen (tPA-ag) were measured.

RESULTS

Median IL-6 concentrations were increased by 208% and 248% in GHD patients compared to BMI-matched and nonobese controls, respectively. Median CRP and tPA-ag levels were increased by 237% and 167% in patients compared to nonobese controls, but not significantly different compared to BMI-matched controls. Plasma levels of fibrinogen and PAI-1 activity did not differ between groups. Age, low-density lipoprotein (LDL) cholesterol, tPA-ag and IL-6 were positively correlated, and IGF-I was negatively correlated to IMT in the patient group, but only age and IL-6 were independently related to IMT.

CONCLUSIONS

IL-6 concentrations were increased in GHD patients compared to controls and independently related to IMT in patients. This finding may help to explain the variance in IMT and the increased vascular morbidity and mortality in hypopituitary patients with GHD.

Body composition and quality of life as markers of the efficacy of growth hormone replacement therapy in adults

Growth hormone (GH) replacement therapy in GH-deficient adults should be initiated with a low dose, independent of body weight or body surface area. Measurements of serum insulin-like growth factor I (IGF-I) concentrations, as well as clinical examinations aimed at detecting signs of fluid excess, are important as safety markers to avoid overtreatment with GH. At present, there is no optimal marker for the long-term efficacy of GH replacement therapy. The long-term maintenance dose of GH should, therefore, be titrated in each individual based on the clinical response, with the aim of normalizing body hydration, other measurements of body composition, quality of life and well-being, and biochemical indices such as serum IGF-I concentration.

Growth hormone alone or combined with metoprolol preserves cardiac function after myocardial infarction in rats

BACKGROUND AND OBJECTIVE

Beta-adrenoreceptor blocking agents are important for the treatment of myocardial infarction (MI). Accumulating evidence also indicates that growth hormone (GH) improves cardiac function after MI in rats. We aimed to investigate the cardiovascular effects of combined treatment in an animal model of MI.

METHODS

MI was induced in rats by ligation of the left coronary artery. Three days after MI, animals were randomly assigned to one of four groups: controls (C) (n=19); GH (n=19) receiving s.c. 2 mg/kg per day rhGH; metoprolol (M) group (n=19) receiving 24 mg/kg per day and combined group (GHM) (n=20) treated with both GH (2 mg/kg per day s.c.) and M (24 mg/kg per day) for 9 days. Transthoracic echocardiography was performed before and after treatment.

RESULTS

Serum levels of insulin-like growth factor I were significantly elevated in the GH-group but not in the GHM group compared to controls. Left ventricular volumes, cardiac index, systolic blood pressure, were similar in all groups. Percent changes in ejection fraction compared to baseline were; GH (6.1+/-5.0%) and GHM (6.1+/-4.2%) vs. C (-12.5+/-3.0%), P<0.01, M (-7.3+/-4.2%). The occurrence of aneurysms was not significantly different between the various treatment regimes.

CONCLUSION

Treatment with growth hormone alone or in combination with metoprolol preserved left ventricular function after MI.

Currently used growth-promoting treatment of children results in normal bone mass and density. A prospective trial of discontinuing growth hormone treatment in adolescents

BACKGROUND AND AIMS

The need for continued GH replacement in patients with childhood-onset GH deficiency (GHD) into adulthood has been recognized. The consequences of discontinuing GH treatment on bone mineralization in adolescent patients with GHD and short stature were examined over a period of 2 years.

PATIENTS

Forty adolescents (aged 16-21 years) treated with GH for more than 3 years and 16 closely matched healthy controls were studied. After a baseline visit, GH treatment was discontinued. The patients were then re-examined with the same protocol after 1 and 2 years. Twenty-one patients had continuing severe GHD into adulthood, while 19 patients were regarded as having sufficient endogenous GH secretion (GHS).

RESULTS

At baseline, there were no differences between the groups in total bone mineral content (BMC) or bone mineral density (BMD). After 2 years without GH treatment, BMC increased similarly in the GHD and GHS groups. BMC of the lumbar spine (L2-L4) increased only in the GHD group. Lumbar spine BMD increased in the GHD and the GHS groups. No changes were observed in the femoral neck region. Biochemical measurements showed that carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) and bone specific alkaline phosphates (ALP) were higher in the GHD and GHS groups at baseline compared with controls. Osteocalcin, carboxy-terminal propeptide of type I procollagen (PICP), ICTP and ALP decreased during the 2 years off treatment in both the GHD and GHS groups. PICP was also lower after 2 years in the GHD group compared with both the GHS group and controls.

CONCLUSIONS

After discontinuation of GH therapy in adolescents at or near final height, there was a continued increase in BMC and BMD both for adolescents with growth hormone deficiency and for those classified as growth hormone sufficient. These groups did not differ from controls at baseline or after 2 years. In the growth hormone deficiency group, biochemical markers for bone formation decreased to levels below those in the growth hormone sufficient and healthy control groups. Although the number of patients and controls in this study were small, the results indicate that the present treatment of Swedish GH-deficient children to final height results in normal BMD.

Healthcare consumption decreases in parallel with improvements in quality of life during GH replacement in hypopituitary adults with GH deficiency

The morbidity associated with GH deficiency (GHD) in adults is now well established. Furthermore, many controlled clinical trials have demonstrated the efficacy of GH replacement therapy. The aim of the present study was to determine whether the effects of GH replacement in adults are reflected in a reduced use of healthcare resources, in addition to improving quality of life (QoL). Data concerning visits to the doctor, number of days in hospital, and amount of sick leave were obtained from patients included in KIMS (Pharmacia International Metabolic Database), a large pharmacoepidemiological survey of hypopituitary adults with GHD, for 6 months before GH treatment and for 6-12 months after the start of treatment. Assistance required with normal daily activities was recorded at baseline and after 12 months of GH therapy. QoL (assessed using a disease-specific questionnaire, QoL-Assessment of GHD in Adults) and satisfaction with physical activity during leisure time were also assessed. For the total group (n = 304), visits to the doctor, number of days in hospital, and amount of sick leave decreased significantly (P < 0.05) after 12 months of GH therapy. Patients also needed less assistance with daily activities, although this was significant (P < 0.01) only for the men. QoL improved after 12 months of GH treatment (P < 0.001), and both the amount of physical activity and the patients' satisfaction with their level of physical activity improved after 12 months (P < 0.001). In conclusion, GH replacement therapy, in previously untreated adults with GHD, produces significant decreases in the use of healthcare resources, which are correlated with improvements in QoL.

GH is needed for the maturation of muscle mass and strength in adolescents

The postpubertal period and the early years of adulthood may be of importance for continuing tissue maturation of importance in adulthood and aging. An example of this is the peak bone mass. This study has evaluated the importance of GH for lean mass and muscle strength in adolescents and young adults. GH treatment was discontinued in 40 adolescents aged 16-21 yr with GH deficiency of childhood onset. Measurements of isometric and isokinetic knee-extensor and flexor strength, handgrip strength, lean body mass, fat-free mass, and total body nitrogen were performed annually for 2 yr. Two hundred fifty healthy adolescents were randomly selected for prospective measurements of lean mass and handgrip strength between the ages of 17 and 21 yr. In the adolescents with continuing GH deficiency, lean body mass decreased, compared with the patients defined as having sufficient endogenous GH. The isometric strength in knee flexors increased in the sufficient endogenous GH group and was unchanged in the GH deficiency group during the 2 yr off GH treatment (between group, P < 0.05). The mean and peak handgrip strength increased on average by 9-15% in the group with sufficient endogenous GH and was unchanged in those with GH deficiency (P < 0.05). Lean body mass and handgrip strength (both, P < 0.001) increased in both the healthy boys and girls who were followed for 4 yr with a more marked increase in the boys. The mean increase in handgrip between the age of 17 and 21 yr was 7-9%. The increased lean mass and improved muscle performance seen in healthy adolescents did not occur in adolescents with GH deficiency. These findings suggest that GH is of importance for the maturation of lean mass and muscle strength in adolescents and young adults.

Visceral obesity and the role of the somatotropic axis in the development of metabolic complications

It is well recognized that aberrant fat localization such as visceral obesity rather than total body fat mass is a major risk factor for cardiovascular disease and type 2 diabetes mellitus. During recent decades, several studies have described a range of metabolic disturbances associated with abdominal obesity, including glucose intolerance, hyperinsulinaemia, insulin resistance, hypertension and dyslipoproteinaemia, now widely known as the metabolic syndrome. Several abnormalities in the hypothalamic-pituitary axis have been described associated with visceral obesity, suggesting a central neuroendocrine dysregulation including increased cortisol concentration and impaired gonadotropin and growth hormone (GH) secretion. Some steps in the chain of events in this theory still remain unclear, however, although these findings have introduced new therapeutic possibilities. These include therapy with sex steroids in both viscerally obese men and women, and several attempts to use GH to treat the endocrine abnormalities present in visceral obesity. The results of these studies are promising, but the therapies are still not recommended for general use.

Similar cardiovascular effects of growth hormone and insulin-like growth factor-I in rats after experimental myocardial infarction

Accumulating data show that growth hormone (GH) and insulin-like growth factor-I (IGF-I) have major effects on the cardiovascular system. In the present study we have directly compared GH and IGF-I in an in vivo rat model of experimental myocardial infarction. Four weeks after ligation of the left coronary artery, male rats were treated with recombinant human (rh) GH 1.1 mg/kg per day, rhIGF-I 3.0 mg/kg per day or saline s.c. for 2 weeks. Transthoracic echocardiography was performed before and after the treatment period. Both GH and IGF-I reduced total peripheral resistance (P< 0.01), end-systolic wall stress (P< 0.01) and end-systolic short-axis area (P< 0.001 and P< 0.05). GH also increased area fractional shortening (P< 0.05). Stroke volume (SV) and SV index were improved by IGF-I (P< 0.0001), and SV tended to be increased by GH (P= 0.12). In conclusion, GH and IGF-I had similar beneficial effects on systolic function and peripheral resistance after experimental myocardial infarction.

The influence of growth hormone deficiency, growth hormone replacement therapy, and other aspects of hypopituitarism on fracture rate and bone mineral density

To assess the influence of factors affecting fracture risk and bone density in adult hypopituitary patients with growth hormone deficiency (GHD), data from a large-scale pharmacoepidemiological survey (the Pharmacia & Upjohn International Metabolic Database [KIMS]) were analyzed and compared with data from a control population (the European Vertebral Osteoporosis Study [EVOS]). The KIMS group consisted of 2084 patients (1112 men and 972 women) with various types of pituitary disease and EVOS consisted of 1176 individuals (581 men and 595 women). Fracture and bone mineral density (BMD) data were available from 2024 patients from the KIMS group and 392 patients from EVOS. The prevalence of fractures in patients with hypopituitarism was 2.66 times that in the non-GH-deficient EVOS population. Adult-onset hypopituitarism with GHD was associated with a higher fracture risk than childhood-onset disease, and patients with isolated GHD had a similar prevalence of fractures to those with multiple pituitary hormone deficiencies. Hormonal replacement therapy with L-thyroxine, glucocorticoids, and sex steroids did not affect the risk of fracture in KIMS patients. In addition, fracture rates in KIMS were independent of body mass index (BMI) and the country of origin. However, smoking was associated with a higher fracture rate in this group. In summary, this is the first large-scale analysis to support the hypothesis of an increased fracture risk in adult patients with hypopituitarism and GHD. This increased risk appears to be attributable to GHD alone, rather than to other pituitary hormone deficiencies or to their replacement therapy.

Effects of growth hormone and its secretagogues on bone

The growth hormone (GH)/insulin-like growth factor-1 axis is not only of importance for linear body growth during childhood, but it is also one of the major determinants of adult bone mass. Studies show that GH treatment increases bone mass in rodents as well as in adult GH-deficient humans, but the effect of GH treatment on bone mass in healthy humans has so far not been impressive. Recently, a new class of GH secretagogues (GHSs) has been developed. In humans, GHS treatment affects biochemical markers of bone turnover and increases growth velocity in selected short children with or without GH deficiency. In rodents, GHS treatment increase bone mineral content, but it has not yet been shown that GHS treatment can affect bone mass in adult humans.

The effect of four weeks of supraphysiological growth hormone administration on the insulin-like growth factor axis in women and men. GH-2000 Study Group

Measurements of serum insulin-like growth factor I (IGF-I) and related markers are routinely used in the diagnosis and treatment of GH deficiency and excess. The validity of these markers for assessment of exogenous GH exposure in healthy adults is, however, unknown. We therefore conducted a double blind, placebo-controlled GH treatment trial in 99 healthy subjects [49 women and 50 men; mean +/- SE age, 25.6+/-0.6 (women)/25.7+/-0.6 yr (men)]. Blood was collected weekly during a 4-week treatment period (days 1-28), and the subjects were subsequently followed for additional 8 weeks (days 29-84). The treatment arms included: I) 0.1 IU/kg x day GH (n = 30; GH 0.1), II) 0.2 IU/kg x day GH (n = 29; GH 0.2), and III) placebo (n = 40). At baseline no gender-specific differences existed, except that the acid-labile subunit (ALS) levels were higher in females. Serum insulin-like growth factor I (IGF-I) levels in males receiving GH increased significantly through day 42 with no significant difference between the 2 doses. The absolute IGF-I response was significantly lower in females, and there was a clear dose-response relationship. ALS levels in males increased through day 30 (P < 0.001). In females ALS levels were only modestly increased on day 28 compared with those in the placebo group (P < 0.02). IGF-binding protein-3 (IGFBP-3) levels in males increased significantly in the GH 0.1 and the GH 0.2 groups on day 30 (P < 0.03), whereas no solid IGFBP-3 increase was detected in females. IGFBP-2 levels decreased insignificantly during GH exposure in both genders. A gender-specific upper normal range for each analyte was arbitrarily defined as 4 SD above the mean level at baseline. On the basis of IGF-I levels alone, GH exposure in the GH 0.2 group was detected in 86% of the males and in 50% of the females on day 21. On day 42 GH exposure was only weakly detectable in males and was not detectable in females. We conclude that 1) males are significantly more responsive than females to exogenous GH; 2) the increase in IGF-I is more robust compared with those in IGFBP-3 and ALS; 3) IGFBP-2 changes very little during GH treatment; and 4) among IGF-related substances, IGF-I is the most specific marker of supraphysiological GH exposure.

The activity of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system in relation to waist/hip circumference ratio in men

OBJECTIVE

To investigate possible differences, between generally and abdominally obese men, in activity and regulation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system.

RESEARCH METHODS AND PROCEDURES

Fifty non-diabetic, middle-aged men were selected to obtain two groups with similar body mass index (BMI) but different waist/hip circumference ratio (WHR). Measurements were performed of the activity of the HPA axis and the sympathetic nervous system, as well as metabolic and endocrine variables.

RESULTS

Men with a high WHR, in comparisons with men with a low WHR, had higher insulin, glucose, and triglyceride values in the basal state and higher glucose and insulin after an oral glucose tolerance test. Men with high WHR had elevated diurnal adrenocorticotropic hormone (ACTH) values but similar cortisol values, except lower cortisol values in the morning. Diurnal growth hormone concentrations showed reduced peak size. Stimulation of the HPA axis with corticotropin-releasing hormone (CRH) and laboratory stress showed no difference in ACTH values between groups, but cortisol values were lower in men with high WHR. In comparison with men with a low WHR, men with a high WHR had elevated pulse pressure and heart rate in the basal state and after challenges by CRH and laboratory stress. They also had increased urinary excretion of catecholamine metabolites.

DISCUSSION

These results suggest a mild dysregulation of the HPA axis, occurring with elevated WHR independent of the BMI. The results also indicate a central activation of the sympathetic nervous system, such as in the early phases of hypertension, correlating with insulin resistance.

Growth hormone deficiency and replacement in elderly hypopituitary adults. KIMS Study Group and the KIMS International Board. Pharmacia and Upjohn International Metabolic Database

OBJECTIVE

Although elderly hypopituitary adults demonstrate an increase in total and central fat compared with age-matched controls and are distinguishable from control subjects in terms of growth hormone (GH) responsiveness on dynamic testing, there are few data available on response to GH replacement. The objective of this study was to compare the baseline characteristics and longitudinal response to GH replacement in patients aged > 65 years with that observed in younger patients enrolled in KIMS (Pharmacia and Upjohn International Metabolic Database). KIMS is a physician-managed, open, long-term surveillance study of adult GH-deficient patients receiving GH replacement. Patients were entered and data provided by interested physicians.

PATIENTS

Baseline characteristics were studied in 109 patients (66 males) aged > 65 years commencing GH replacement at time of entry into KIMS and the effects of GH replacement on blood pressure, lipids and quality of life in 64 patients who had completed at least 6 months of GH replacement. Data were compared with baseline data on 863 patients aged < 65 years with adult onset GH deficiency, who had not received GH for at least 6 months prior to entry into KIMS, 220 of whom went on to complete > 6 months GH therapy in KIMS.

RESULTS

Blood pressure, cholesterol and LDL cholesterol were positively correlated with age, particularly in females, and older patients had a predictably higher prevalence of diabetes mellitus and history of hypertension. The frequency of previous fractures was increased in females but not in males aged > 65 years. Body mass index, waist/hip ratio and quality of life (AGHDA score) was similar in both groups prior to commencement of GH therapy. GH replacement doses were similar in younger and older patients and the percentage of patients with serum IGF-I of > 2SD above the age-related normal mean was not significantly different between the groups (< 65 years, 20%; > 65 years, 11%). After 6 months of GH replacement significant improvements were evident in waist circumference, waist/hip ratio, diastolic blood pressure, total and LDL cholesterol and AGHDA score in patients aged < 65 years. Similar significant reductions in total and LDL cholesterol were evident in patients > 65 years. In addition, male patients aged > 65 years demonstrated significant reductions in diastolic blood pressure and AGHDA score but no change in waist circumference whereas females aged > 65 years demonstrated a trend to reduction in waist circumference and AGHDA score.

CONCLUSIONS

These data, derived from the largest series of GH-treated hypopituitary patients published to date, confirm similar baseline characteristics and positive benefit from GH replacement in older compared with younger hypopituitary patients particularly in relation to quality of life.

The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats

Growth hormone (GH) is of importance for normal bone remodelling. A recent clinical study demonstrated that MK-677, a member of a class of GH secretagogues (GHSs), increases serum concentrations of biochemical markers of bone formation and bone resorption. The aim of the present study was to investigate whether the GHSs, ipamorelin (IPA) and GH-releasing peptide-6 (GHRP-6), increase bone mineral content (BMC) in young adult female rats. Thirteen-week-old female Sprague-Dawley rats were given IPA (0.5 mg/kg per day; n=7), GHRP-6 (0.5 mg/kg per day; n=8), GH (3.5 mg/kg per day; n=7), or vehicle administered continuously s.c. via osmotic minipumps for 12 weeks. The animals were followed in vivo by dual X-ray absorptiometry (DXA) measurements every 4th week. After the animals were killed, femurs were analysed in vitro by mid-diaphyseal peripheral quantitative computed tomography (pQCT) scans. After this, excised femurs and vertebrae L6 were analysed by the use of Archimedes' principle and by determinations of ash weights. All treatments increased body weight and total tibial and vertebral BMC measured by DXA in vivo compared with vehicle-treated controls. However, total BMC corrected for the increase in body weight (total BMC:body weight ratio) was unaffected. Tibial area bone mineral density (BMD, BMC/area) was increased, but total and vertebral area BMDs were unchanged. The pQCT measurements in vitro revealed that the increase in the cortical BMC was due to an increased cross-sectional bone area, whereas the cortical volumetric BMD was unchanged. Femur and vertebra L6 volumes were increased but no effect was seen on the volumetric BMDs as measured by Archimedes' principle. Ash weight was increased by all treatments, but the mineral concentration was unchanged. We conclude that treatment of adult female rats with the GHSs ipamorelin and GHRP-6 increases BMC as measured by DXA in vivo. The results of in vitro measurements using pQCT and Archimedes' principle, in addition to ash weight determinations, show that the increases in cortical and total BMC were due to an increased growth of the bones with increased bone dimensions, whereas the volumetric BMD was unchanged.

Cost of illness in adult patients with hypopituitarism

OBJECTIVE

To compare the healthcare costs of patients with hypopituitarism with those of individuals from the general population.

DESIGN

A retrospective study of costs over 1 year. Estimates of direct and indirect health-related costs were calculated for patients from the general population using existing databases, and for patients with hypopituitarism using records of all patients eligible to participate on 31 December 1989 who could be traced, were willing to participate and had not been treated for acromegaly or Cushing's disease.

SETTING

The catchment area of the Endocrine Unit, Sahlgrenska Hospital, Gothenburg. The study was conducted from the societal perspective. Reference data were collected from official regional and national registries.

PATIENTS

199 patients with adult-onset hypopituitarism in whom replacement therapy was given to maintain the adrenal, thyroid and gonadal (but not the somatotropic) axes.

MAIN OUTCOME MEASURES AND RESULTS

Direct and indirect costs incurred by patients with hypopituitarism were higher than those incurred by individuals from the general population. The total direct costs per patient were Swedish Crowns (SEK)22,920 vs SEK12,080 (p < 0.003) in the general population, and the highest costs were related to inpatient care. Of the patients aged 16 to 64 years, 22% had drawn a disability pension versus the expected 11.3% (p < 0.003) in the general population, and the patients had a mean sick leave of 38.4 days vs 23.5 (p < 0.001). Total excess costs for all patients with hypopituitarism were SEK 35,768 per patient (p < 0.007).

CONCLUSIONS

Patients with hypopituitarism incur more health-related costs than individuals from the general population. They also take more sick leave days and are more likely to claim a disability pension than members of the general population. Further cost analyses are needed to determine whether improvements in diagnostic and surgical procedures, and hormone replacement therapy, can reduce the healthcare costs of patients with hypopituitarism.

A nine-month, placebo-controlled study of the effects of growth hormone treatment on lipoproteins and LDL size in abdominally obese men

Abdominal/visceral obesity is associated with blunted growth hormone (GH) secretion and an unfavourable lipoprotein pattern. In this study, the effect of GH treatment on LDL size and on serum lipoprotein concentrations was determined in abdominally obese men. Thirty men, aged 48-66 years, with a body mass index (BMI) of 25-35 kg/m(2)and a waist:hip ratio of >0.95, received treatment with GH (9. 5 microg/kg/day) or placebo for 9 months. Serum concentrations of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) were reduced (P<0.05, P<0.05 and P<0.001 vs placebo, respectively). Serum lipoprotein(a) [Lp(a)] concentration increased (P<0.05 vs. placebo). Mean low density lipoprotein (LDL) particle diameter was marginally increased by active treatment as compared with placebo (P =0.08). No changes were observed in the serum concentrations of high density lipoprotein-cholesterol (HDL-C), apolipoprotein A-I (apoA-I) and apolipoprotein E (apoE). In conclusion, 9 months of GH treatment in abdominally obese men beneficially reduced serum concentrations of TC, LDL-C and apoB, and marginally increased mean LDL diameter, while serum Lp(a) increased. The ultimate effect of GH therapy on the cardiovascular risk remains, however, to be determined.

Treatment of acromegaly with the growth hormone-receptor antagonist pegvisomant

BACKGROUND

Patients with acromegaly are currently treated with surgery, radiation therapy, and drugs to reduce hypersecretion of growth hormone, but the treatments may be ineffective and have adverse effects. Pegvisomant is a genetically engineered growth hormone-receptor antagonist that blocks the action of growth hormone.

METHODS

We conducted a 12-week, randomized, double-blind study of three daily doses of pegvisomant (10 mg, 15 mg, and 20 mg) and placebo, given subcutaneously, in 112 patients with acromegaly.

RESULTS

The mean (+/-SD) serum concentration of insulin-like growth factor I (IGF-I) decreased from base line by 4.0+/-16.8 percent in the placebo group, 26.7+/-27.9 percent in the group that received 10 mg of pegvisomant per day, 50.1+/-26.7 percent in the group that received 15 mg of pegvisomant per day, and 62.5+/-21.3 percent in the group that received 20 mg of pegvisomant per day (P<0.001 for the comparison of each pegvisomant group with placebo), and the concentrations became normal in 10 percent, 54 percent, 81 percent, and 89 percent of patients, respectively (P<0.001 for each comparison with placebo). Among patients treated with 15 mg or 20 mg of pegvisomant per day, there were significant decreases in ring size, soft-tissue swelling, the degree of excessive perspiration, and fatigue. The score fortotal symptoms and signs of acromegaly decreased significantly in all groups receiving pegvisomant (P< or =0.05). The incidence of adverse effects was similar in all groups.

CONCLUSIONS

On the basis of these preliminary results, treatment of patients who have acromegaly with a growth hormone-receptor antagonist results in a reduction in serum IGF-I concentrations and in clinical improvement.

Pituitary adenomas in Sweden between 1958 and 1991: incidence, survival, and mortality

The objective of the present study was to determine the incidence of pituitary adenomas (PAs) and the associated rates and causes of mortality in a large population. The study population comprised 2279 patients (1010 women and 1269 men) of all individuals (n = 3321) with pituitary tumors included in the Swedish Cancer Registry between 1958 and 1991. The mean age (+/-SD) at diagnosis was 52.3 +/-15.7 yr. The age-standardized incidence of PA increased significantly from approximately 6 cases/million inhabitants in 1958 to 11 cases/ million in 1991. The age-specific incidence peaked between 60-70 yr of age in both sexes. Excess mortality was found in the study population. The total number of deaths was 842. The standardized mortality ratio (SMR) for the study population was 2.0. The SMR for women (2.3) was significantly (P < 0.01) higher than that for men (1.9). Cardiovascular diseases were the most common cause of mortality among patients, accounting for 346 deaths (SMR, 1.6). The difference between the sexes was significant (men, 1.4; women, 1.8; P < 0.05). Cerebrovascular death occurred in 97 patients (SMR, 2.4), with no significant difference between men (SMR, 2.5) and women (SMR, 2.2). Excess mortality was also observed for tumors, endocrine diseases, and gastrointestinal diseases. These findings suggest that the annual incidence of PA is increasing. Possible explanations are improved diagnostic skill and/or increased awareness of pituitary diseases among physicians. However, a real increase in the incidence of PA cannot be ruled out.

Growth hormone and ageing

The proportion of elderly people is steadily growing in Western societies. The result is a disproportionate accumulation of the oldest and most vulnerable sector of the population, suffering from frailty-associated disorders and cardiovascular diseases. Growth hormone (GH) secretion declines progressively during adulthood. In ageing and severe GH deficiency, an individual's muscle mass, muscle strength and bone mass are decreased, and the relative proportion of total and visceral fat is increased. An association between reduced GH levels and the catabolism of ageing has been suggested. GH or GH secretagogue treatment could be of value to minimize the health-related consequences associated with the ageing process.

Treatment of growth hormone deficiency in adults

In analogy with other hormonal replacement therapy GH treatment should be commenced with a low starting dose, independent of body weight or body surface area. Hormonal replacement should mimic the normal physiology to minimize the risk of side effects in the life-long replacement of adults. We should, therefore, consider individual responsiveness and also be aware of the difference between pattern of GH under normal condition and during s.c. administration. The safety and monitoring of GH replacement therapy in adults have been addressed in the Growth Hormone Research Society Consensus Guidelines for Diagnosis and Treatment of Adults with GH Deficiency from the Port Stephens Workshop, April 1997. Besides finding better and more accurate biochemical markers for choosing correct GH replacement dose, future research should address the long-term benefits and safety with GH replacement in adults, with special emphasize on incipient risks in terms of cardiovascular disease and of neoplasia, in particular.

GH and bone--experimental and clinical studies

GH increases bone formation both via a direct interaction with GH receptors on osteoblasts and via locally produced IGF-I (autocrine/paracrine action). GH deficiency results in decreased bone mass in both man and laboratory animals and treatment of GHD patients with GH for several months results in increased bone mass. GH treatment also increases bone mass and the total mechanical strength of bones in rats with normal GH secretion. Because of the short duration of GH-treatment in man with normal GH secretion, the effect on bone mass is still inconclusive. The action of GH on bone metabolism in GHD adults is twofold: It stimulates both bone resorption and bone formation. A "Biphasic model" of GH action in bone remodeling has recently been proposed [1] (Fig. 2). According to this model the net effect of GH first results in a loss of bone mass, followed by a net increase in bone mass. The transition point occurs when bone formation proceeds at a higher rate than bone resorption. Taking all clinical studies of GH-treatment of GHD adults into account, it appears that the "transition point" occurs after approximately six months and that a net increase in bone mass usually is seen after 12-18 months of GH treatment. It should be emphasized that the "Biphasic model" of GH action in bone remodeling is proposed based on findings in GHD adults, and it remains to be clarified whether or not it is valid for subjects with normal GH secretion.

Growth hormone abuse

Doping with growth hormone (GH) has become an increasing problem in sports during the last 10 years. GH has a reputation of being fairly effective among GH users, although the effectiveness is not undisputed, and the few controlled studies that have been performed with supraphysiological GH doses to athletes have shown no significant positive effects of GH in the aspect of a doping agent. There is no method yet to discover GH doping, but current intensive research in this matter will hopefully produce a method in the years to come. This article describes the GH physiology, the clinical use of GH, the athlete's view, administration regimens and side effects.

Calcaneal ultrasound measurements are determined by age and physical activity. Studies in two Swedish random population samples

AIM

To present reference values and correlations with body composition, blood variables and lifestyle factors.

SUBJECTS

Two random population samples from Göteborg, Sweden, one comprising 184 men and 455 women aged 25-64 years (MONICA) and the other 860 women aged 55-82 years (BEDA) were studied.

METHODS

Calcaneal ultrasound measurement (LUNAR Achilles) and bioimpedance were measured. Smoking habits, coffee consumption, physical activity, psychological stress, education and marital status, as well as blood lipids, blood pressure, and fractures were studied.

RESULTS

Broadband ultrasound attenuation and stiffness were higher in men than in women (P < 0. 001), but speed of sound did not differ between sexes. Speed of sound, broadband ultrasound attenuation and stiffness decreased with age (P < 0.001). In both sexes speed of sound, broadband ultrasound attenuation and stiffness correlated positively to body size variables, and negatively with smoking in women after adjustment for age. Speed of sound, broadband ultrasound attenuation and stiffness were positively related to physical activity in both sexes, and these relationships were the only ones that remained in multivariate analyses in addition to age (negative). Osteoporotic fractures increased with age. Speed of sound, broadband ultrasound attenuation and stiffness were lower amongst women with osteoporotic fractures.

CONCLUSION

Speed of sound, broadband ultrasound attenuation and stiffness decreased with age and increased with physical activity, but body weight and height were not correlated in multivariate analyses. Osteoporotic fractures increased with age and were associated with lower calcaneal ultrasound values.

The growth hormone secretagogue hexarelin improves cardiac function in rats after experimental myocardial infarction

Several studies have shown that GH can enhance cardiac performance in rats after experimental myocardial infarction and in humans with congestive heart failure. In the present study, the hemodynamic effects of hexarelin (Hex), an analog of GH-releasing peptide-6 and a potent GH secretagogue, were compared with the effects of GH. Four weeks after ligation of the left coronary artery male rats were treated sc twice daily with hexarelin [10 microg/kg x day (Hex10) or 100 microg/kg x day (Hex100)], recombinant human GH (2.5 mg/kg x day), or 0.9% NaCl for 2 weeks. Transthoracic echocardiography was performed before and after the treatment period. GH, but not Hex, increased body weight gain. GH and Hex100 decreased total peripheral resistance (P < 0.05) and increased stroke volume (P < 0.05 and P < 0.01, respectively) and stroke volume index (P = 0.06 and P < 0.01, respectively) vs. NaCl. Cardiac output was increased by GH and Hex100 (P < 0.05), and cardiac index was increased by Hex100 with a borderline significance for GH (P = 0.06). In conclusion, Hex improves cardiac function and decreases peripheral resistance to a similar extent as exogenous GH in rats postmyocardial infarction. The mechanisms of these effects are unclear; they could be mediated by GH or a direct effect of Hex on the cardiovascular system.

Responses of markers of bone and collagen turnover to exercise, growth hormone (GH) administration, and GH withdrawal in trained adult males

To examine the interactions between acute exercise and GH on markers of bone and collagen turnover and to assess the potential for detecting GH abuse in athletes using these markers, we studied 17 aerobically trained males (age, 26.9+/-1.5 yr). Sequential studies of exercise, GH administration, and GH withdrawal were undertaken. A randomized, controlled study of rest vs. exercise showed that exercise did not change serum osteocalcin; other markers of formation increased transiently (each P<0.001): bone-specific alkaline phosphatase (+16.1%), carboxyterminal propeptide of type I procollagen (+14.1%), and procollagen III N-terminal extension peptide (+5.0%). The carboxyterminal cross-linked telopeptide of type I collagen, a bone resorption marker, increased 9.7% (P = 0.018) in response to exercise. A randomized, double blind, placebo-controlled, parallel study of recombinant human GH treatment (0.15 IU/kg x day) for 1 week increased serum osteocalcin (net increase preexercise, +/-10.0%; P = 0.017), carboxyterminal propeptide of type I procollagen (+17.6%; P = 0.002), procollagen III N-terminal extension peptide (+48.4%; P = 0.001), and carboxyterminal cross-linked telopeptide of type I collagen (53.3%; P = 0.009). Disappearance half-times after cessation of recombinant human GH for pre- and postexercise markers ranged from 248-770 h. We conclude 1) endurance exercise transiently activates bone and collagen turnover; 2) brief GH administration results in similar but quantitatively greater augmentation; and 3) these data will assist in designing a GH detection strategy.

Discontinuation of growth hormone (GH) treatment: metabolic effects in GH-deficient and GH-sufficient adolescent patients compared with control subjects. Swedish Study Group for Growth Hormone Treatment in Children

The need for continuing GH replacement in patients with childhood-onset GH deficiency continuing into adulthood has been recognized. The metabolic consequences of discontinuing GH in adolescent patients with childhood-onset GH deficiency and short stature were examined over a period of 2 yr. Forty adolescents (aged 16-21 yr) receiving GH treatment for more than 3 yr and 16 closely matched healthy controls were studied. After a baseline visit, GH treatment was discontinued. The patients were then examined with the same protocol once a year for 2 yr. Twenty-one patients had severe GH deficiency (GHD) into adulthood, whereas 19 patients were regarded as having sufficient endogenous GH secretion (GHS). After 2 yr without GH treatment, the serum insulin-like growth factor I level was lower in GHD than in both GHS and control subjects. Both before and 2 yr after GH treatment was discontinued, serum concentrations of total cholesterol (C), low density lipoprotein C, and apolipoprotein B were higher in the GHD than in both GHS and control subjects. Serum concentrations of high density lipoprotein C decreased in the GHD group and increased in the other 2 study groups. The amount of total body and abdominal fat mass throughout the study and the increment in these masses were more marked in the GHD than in the GHS and control subjects when GH treatment was discontinued. The discontinuation of GH therapy in adolescents with severe GHD continuing into adulthood results over a period of 2 yr in the accumulation of important cardiovascular risk factors that are associated with GHD in adults.

The effects of treatment and the individual responsiveness to growth hormone (GH) replacement therapy in 665 GH-deficient adults. KIMS Study Group and the KIMS International Board

Data from 665 adults with GH deficiency (GHD; 332 women; 169 childhood-onset GHD; mean age, 44 yr) were analyzed to determine the efficacy of and individual responsiveness to GH replacement therapy. GH replacement was started at enrolment into KIMS (Pharmacia & Upjohn, Inc. International Metabolic Database). Mean maintenance doses of GH after 6 and 12 months were 0.43 and 0.53 mg/day (1.3 and 1.6 IU/day) for men and women, respectively. Serum insulin-like growth factor I (IGF-I) SD score increased from -2.2 and -4.2 in men and women, respectively, to 1.8 and -0.9 at 6 months and 0.8 and -0.7 at 12 months. The waist/hip ratio decreased after 6 and 12 months, with the changes more pronounced in men. The waist/hip ratio was not influenced by age of onset of GHD, severity of hypopituitarism, or gonadal status. Total cholesterol decreased significantly in men, and high density lipoprotein cholesterol increased in women. Systolic blood pressure was unchanged during GH therapy, but diastolic blood pressure decreased in women. Quality of life, determined by a specific questionnaire for assessment of GHD in adults, improved after 6 and 12 months of GH therapy; this was more pronounced in adult-onset than in childhood-onset GHD, but was not influenced by gender, severity of hypopituitarism, or gonadal status. In 80% of patients, the starting dose of GH was 0.27 mg/day or less. This and the absence of a correlation between body weight and change in IGF-I were consistent with a dose-titration approach, which would tend to obscure individual variations in responses (determined by IGF-I levels). Nonetheless, the increase in IGF-I was significantly higher in men than in women on similar mean GH doses. Weak correlations were observed between the maintenance dose of GH and the change in IGF-I in men and women receiving sex steroid replacement, but not in patients with untreated hypogonadism or an intact gonadotropin reserve. Similarly, the increment in IGF-I was not related to the severity of GHD, as determined by the number of additional pituitary hormone deficiencies. Differences in IGF-I generation may partly explain the gender differences in reduction of central adiposity. These data highlight the value of large longitudinal surveillance databases in defining the optimum dose regimen for GH replacement and indicate that women may need a higher replacement dose of GH than men.

Postmenopausal osteoporosis is more related to hormonal aberrations than to lifestyle factors

OBJECTIVE

Serum insulin-like growth factor-1 (IGF-1) decreases with increasing age and this process is more pronounced in women after the menopause in parallel with the increasing prevalence of osteoporosis. This study was designed to compare IGF-1 concentrations, vitamin D, intact parathyroid hormone (PTH) and lifestyle factors in postmenopausal, osteoporotic women with and without oestrogen replacement therapy (HRT), with an age-matched random population sample of women.

DESIGN

Case control study.

PATIENTS

Postmenopausal, osteoporotic women, n = 128, mean age 59 +/- 6 years, were compared with a female random population sample matched for age, n = 227, mean age 59 +/- 5 years, from the WHO MONICA Project, Göteborg, Sweden. Osteoporotic fractures had occurred in 56% of the patients compared with 4% of the controls (P < 0.001).

MEASUREMENTS

Anthropometry, occupation, smoking habits, physical activity, blood pressure, IGF-1, vitamin D, intact PTH, blood lipids.

RESULTS

There were no differences in occupational class, current or previous smoking habits, degree of physical activity during occupational or leisure time between the patients and controls. Osteoporotic women had lower body weight and body mass index than the controls (P < 0.001). Height, waist/hip ratio and osteocalcin were similar. 25(OH) vitamin D and 1,25(OH)2 vitamin D were lower (P < 0.05 and P < 0.01, respectively), PTH was higher (P < 0.001) and IGF-1 lower (P < 0.01) in osteoporotic women compared with the controls. IGF-1 was lower (P < 0.05), in spite of similar bone mineral density, in osteoporotic women without HRT than in those with HRT, who had IGF-1 concentrations similar to those of the population sample, of whom fewer than 10% had HRT. Among patients, IGF-1 did not correlate with serum oestradiol or bone mineral density. PTH correlated negatively to bone mineral density at the femoral site (r = - 0.29; P = 0.003).

CONCLUSION

Osteoporosis in postmenopausal women is more related to hormonal aberrations than to lifestyle factors.

Responses of the growth hormone (GH) and insulin-like growth factor axis to exercise, GH administration, and GH withdrawal in trained adult males: a potential test for GH abuse in sport

GH abuse by elite athletes is currently undetectable. To define suitable markers of GH doping, we assessed the effects of acute exercise, GH administration, and GH withdrawal on the GH/insulin-like growth factor (IGF) axis in athletic adult males. Acute endurance-type exercise increased serum GH, GH-binding protein (GHBP), total IGF-I, IGF-binding protein (IGFBP)-3, and acid-labile subunit (ALS), each peaking at the end of exercise. IGFBP-1 increased after exercise was completed. Free IGF-I did not change with exercise. Recombinant human GH treatment (0.15 IU/kg x day) for 1 week increased serum total IGF-I, IGFBP-3, and ALS, exaggerating the responses to exercise. IGFBP-2 and IGFBP-1 were trivially suppressed. After GH withdrawal, the GH response to identical exercise was suppressed. Total IGF-I, IGFBP-3, and ALS returned to baseline over 3-4 days. In summary, 1) acute exercise transiently increased all components of the IGF-I ternary complex, possibly due to mobilization of preformed intact complexes; 2) GH pretreatment augmented the exercise-induced changes in ternary complexes; 3) postexercise IGFBP-1 increments may protect against delayed onset hypoglycemia; 4) serum total IGF-I, IGFBP-3, and ALS may be suitable markers of GH abuse; and 5) differences in disappearance times altered the sensitivity of each marker for detecting GH abuse.

Treatment of obese subjects with the oral growth hormone secretagogue MK-677 affects serum concentrations of several lipoproteins, but not lipoprotein(a)

Obesity is associated with blunted GH secretion and an unfavorable lipoprotein pattern. The objective of this study was to investigate the effects of treatment with the oral GH secretagogue MK-677 on lipoproteins in otherwise healthy obese males. The study was randomized, double blind, and parallel. Twenty-four obese males, aged 18-50 yr, with body mass index greater than 30 kg/m2 and waist/hip ratio above 0.95 were treated with 25 mg MK-677 (n = 12) or placebo (n = 12) daily for 8 weeks. MK-677 treatment did not significantly change serum lipoprotein(a) [Lp(a)] levels. Serum apolipoprotein A-I and E (apoA-I and apoE) were increased at 2 weeks (P < 0.001 and P < 0.01 vs. placebo, respectively), but were not changed at study end. Serum total cholesterol and low density lipoprotein (LDL) cholesterol (LDL-C) levels were not significantly changed by MK-677 treatment. Serum high density lipoprotein (HDL) cholesterol (HDL-C) was increased at 2 weeks of MK-677 treatment (P < 0.01 vs. placebo), but not at 8 weeks. The LDL-C/HDL-C ratio was reduced after 8 weeks of MK-677 treatment (P < 0.05 vs. placebo). Mean LDL particle diameter was decreased at 2 weeks (P < 0.05 vs. placebo), but was unchanged compared with baseline values at 8 weeks (P = NS vs. placebo). The level of serum triglycerides was increased at 2 (P < 0.05 vs. placebo), but not at 8, weeks. Lipoprotein lipase activity in abdominal and gluteal sc adipose tissue was not affected by active treatment. In conclusion, treatment with the oral GH secretagogue MK-677 affected circulating lipoproteins. The effects on serum apoA-1, apoE, triglycerides, and mean LDL particle diameter were transient. At study end, the LDL-C/HDL-C ratio was decreased. MK-677 treatment did not significantly affect serum Lp(a) concentrations at the present dose and administration protocol.

GH replacement in 1034 growth hormone deficient hypopituitary adults: demographic and clinical characteristics, dosing and safety

OBJECTIVE

Long-term experience of growth hormone (GH) replacement therapy in a large population of hypopituitary adults with GH deficiency (GHD) is limited, and safety surveillance is clearly essential. KIMS, the Pharmacia & Upjohn International Metabolic Database, is a long-term, open, outcomes research programme of hypopituitary adult patients with GHD who are treated in a conventional clinical setting.

PATIENTS

The present analysis encompasses data from 1034 hypopituitary adult GHD patients treated with GH for a total of 818 patient years.

RESULTS

Prior to GH therapy, the KIMS patient population exhibited an increased prevalence of obesity, diabetes mellitus (in females) and hyperlipidaemia, compared with normal populations described in published studies. Quality of life, assessed using a disease-specific questionnaire (QoL-AGHDA), was also reduced in KIMS patients. The maintenance dose of GH was significantly higher in patients who were receiving GH prior to enrolment into KIMS (non-naive patients) compared with patients who commenced GH at the time of enrolment (naive patients). In addition, dose of GH correlated significantly with body weight in the former group of patients. Analysis of serum levels of IGF-I indicated that overtreatment with GH was markedly more common in non-naive than in naive patients. The frequency of adverse events in KIMS patients was no higher than that reported in patients receiving placebo in previous clinical trials. Recurrence of pituitary or CNS tumours was reported in six patients, a rate consistent with data from control series. Three deaths were reported, none of which was obviously associated with GH treatment.

CONCLUSIONS

Our data, drawn from a large population of hypopituitary adults treated with GH for a total of more than 800 patient years, confirm previous reports that untreated GHD in hypopituitary adults is associated with a number of important clinical problems. In addition, the results suggest that there has been a shift in recent years from determination of GH dose on the basis of body weight to dose titration of individual patients, and indicate that the latter technique has important advantages. The data provide further evidence that GH replacement therapy is well-tolerated in adults. However, it is possible that some adverse events may not become evident over the time scale covered by the present analysis, and continued surveillance therefore remains mandatory.

Discrepancy between serum leptin values and total body fat in response to the oral growth hormone secretagogue MK-677

OBJECTIVE

Growth hormone (GH) treatment decreases total body fat while this effect has not yet been documented for the oral GH secretagogue MK-677. In the present study, the effects of MK-677 treatment on serum levels of leptin, thyroid hormones and testosterone were determined.

DESIGN

This was a randomized, double-blind, and parallel study. Twenty-four healthy obese males, 19-49 years of age, with body mass index (BMI) > 30 kg/m2 and a waist:hip ratio > 0.95, were treated with MK-677 (25 mg/day; n = 12) or placebo (n = 12) for 8 weeks.

RESULTS

MK-677 treatment increased serum leptin levels and leptin/body fat ratio at 2 weeks of treatment (P < 0.05 vs. placebo) but no significant change was observed at 8 weeks. An increase in serum free 3, 5, 3'-triiodothyronine (free T3) was not detected until 8 weeks of MK-677 treatment (P < 0.05 vs. placebo). Peak serum thyroid stimulating hormone (TSH) concentration after MK-677 administration was similar to that after placebo administration at initiation of treatment and at 2 weeks. At 8 weeks of MK-677 treatment, mean peak serum TSH concentration was increased (P < 0.05 vs. placebo) although it remained within the normal range. Serum peak values of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were similar after MK-677 and placebo administration. MK-677 treatment reduced serum total testosterone (P < 0.05 vs. placebo) although total testosterone/sex hormone-binding globulin (SHBG) ratio (an index of free testosterone) was not changed.

CONCLUSION

Treatment with the oral GH secretagogue MK-677 transiently increased serum leptin levels and leptin/body fat ratio at 2 weeks of treatment, and increased serum free T3 after 8 weeks. These results indicate that MK-677 treatment is able to affect circulating factors of importance for adipose tissue mass and fuel metabolism.

Double-blind, placebo-controlled study of growth hormone treatment in elderly patients undergoing chronic hemodialysis: anabolic effect and functional improvement

Elderly patients with end-stage renal disease often have protein and/or caloric malnutrition that severely affects general well-being and mortality. Uremia is associated with resistance to the action of growth hormone (GH). This resistance could be of clinical importance in elderly dialysis patients. In the present study, the effects of GH treatment were assessed in elderly patients receiving chronic hemodialysis. Twenty hemodialysis patients with a mean age of 71.7 years (range, 53 to 92 years) were included on a 6-month, randomized, double-blind, placebo-controlled trial of GH treatment. The dose of GH was 66.7 microgram/kg, administered subcutaneously three times weekly immediately after each dialysis session. Body composition was measured using total-body potassium levels, computed tomography of the lower leg, and bioelectrical impedance analysis. Serum albumin concentrations and handgrip strength were also measured. GH treatment increased the serum concentration of insulin-like growth factor-I (IGF-I), IGF-I/IGF-binding protein-3 ratio, fat-free mass, and the serum concentration of albumin compared with placebo. The number of patients with serum albumin levels less than 40 g/L was reduced by a factor of three in the GH-treated group. Handgrip strength increased in response to GH treatment compared with placebo. Six months of GH treatment in elderly hemodialysis patients produced anabolic effects, with improved muscle performance. Also, the number of patients with low albumin levels was markedly reduced, indicating improved nutritional status and/or attenuated catabolism. These are all important beneficial effects for individual patient outcomes.

Growth hormone (GH) therapy in GH-deficient adults influences the response to a dietary load of cholesterol and saturated fat in terms of cholesterol synthesis, but not serum low density lipoprotein cholesterol levels

An increased dietary load of cholesterol (ch) and saturated fat increases serum low density lipoprotein ch (LDL-ch) levels. GH therapy in GH-deficient adults decreases serum LDL-ch levels. In the rat, GH is important for resistance to dietary cholesterol in terms of serum cholesterol levels. The aim of this study was to investigate the influence of GH on the effects of an increase in the intake of cholesterol and saturated fat on serum lipoproteins and markers for cholesterol synthesis in man. Six GH-deficient adults were given an isocaloric diet enriched in cholesterol and saturated fat for 17 days with and without GH therapy (1-1.5 U/day). Serum cholesterol, LDL-ch, apolipoprotein B (apoB), and apoA1 levels increased during the diet period with GH therapy and tended to increase during the diet period without GH. However, GH therapy did not influence the dietary effect on serum cholesterol, LDL-ch, apoA1, or apoB levels. Serum levels of triglycerides, very low density lipoprotein ch, high density lipoprotein ch, and apoE were not affected by diet or GH therapy. GH therapy increased serum lipoprotein(a) levels, but did not affect the response to diet. The serum total delta7-lathosterol/cholesterol ratio increased less during the diet period with GH therapy than during the diet period without GH. Serum 7alpha-hydroxy-4-cholesten-3-one levels tended to increase during both diet periods, but were not influenced by GH treatment. Serum plant sterol levels did not change. These results indicate that GH counteracts an increase in cholesterol synthesis induced by a high fat diet without affecting bile acid synthesis or sterol absorption. GH therapy did not have any major influence on the dietary effects on serum lipoprotein levels.