Bone mineral density in acromegaly: the effect of gender,disease activity and gonadal status

OBJECTIVE: Data on bone mineral density (BMD) in acromegaly are conflicting as most previous studies collectively evaluated eugonadal and hypogonadal patients of both sexes, with or without active disease. We have evaluated BMD in 152 acromegalic patients of both sexes with varying disease activity and gonadal status. DESIGN: Cross-sectional, retrospective. PATIENTS: We studied 152 acromegalic patients (99 women aged 26-72 years, and 53 men aged 21-75 years), 107 with active and 45 with controlled disease. Eighty-five patients had normal gonadal status and 67 were hypogonadal. MEASUREMENTS: In all patients we measured serum GH levels by immunoenzimometric assay, and serum IGF-I levels by radioimmunoassay. BMD was assessed at spine L2-L4 (LS) and at femoral neck (FN) by dual energy X-ray absorptiometry; results are expressed as Z-values. RESULTS: We evaluated the effect of GH excess on bone at different sites in relation to gonadal status, disease activity and gender. At LS, in respect to the reference population, BMD (mean +/- SE) values were higher in eugonadal patients (active: 0.71 +/- 0.29, P < 0.02; controlled: 0.65 +/- 0.28, P < 0.05) and lower in hypogonadal ones (active: -0.64 +/- 0.35, 0.1 < P < 0.05; controlled: -1.05 +/- 0.36, P < 0.01), regardless of disease activity. On the contrary, at FN, BMD was higher than in the reference population, both in eugonadal (1.01 +/- 0.22, P < 0.001) and hypogonadal (0.63 +/- 0.17, P < 0.001) patients only in subjects with active disease, but not in those in which the disease was controlled (eugonadal: 0.31 +/- 0.23, P = ns; hypogonadal 0.04 +/- 0.28, P = ns). We did not observe any difference in BMD values according to gender both at LS (males vs. females -0.02 +/- 0.30 vs. 0.01 +/- 0.24, P = ns) or at FN (0.77 +/- 0.19 vs. 0.63 +/- 0.15, P = ns). CONCLUSIONS: The anabolic effect of GH excess on bone in acromegalic patients is: (i) gender-independent; (ii) evident at the spine only in eugonadal regardless of disease activity; (iii) evident at femoral neck only in the presence of active disease regardless of gonadal status.     

Prevalence of vertebral fractures in men with acromegaly

CONTEXT: Data on osteoporotic fractures in acromegaly are limited. An increased prevalence of radiological vertebral fractures was already observed in postmenopausal women with active acromegaly. It is unknown whether this observation may reflect a more general increased risk of fractures in acromegaly. DESIGN: This was a cross-sectional study. SETTING: The study was conducted at referral centers. PATIENTS AND CONTROL SUBJECTS: Subjects included 40 males with acromegaly (25 patients with controlled disease and 15 patients with active disease) and 31 control males, with age and gonadal status comparable with the patients. INTERVENTIONS: Evaluation of vertebral fractures (quantitative morphometric analysis) and bone mineral density (BMD) at lumbar spine and total hip (dual energy X-ray absorptiometry) was done. MAIN OUTCOME MEASURE: Vertebral fractures were assessed. RESULTS: Although BMD was not significantly different between acromegalic patients and control subjects, the prevalence of vertebral fractures was higher in acromegalic patients as compared with the control subjects (57.5 vs. 22.6%; chi(2): 8.7; P = 0.003). Fractured and nonfractured acromegalic patients showed no significant difference in age and BMD Z-score. However, acromegalic patients with fractures had serum IGF-I values significantly higher and duration of active disease significantly longer with respect to patients without fractures. Moreover, patients with fractures showed significantly longer untreated hypogonadism as compared with patients without fractures. In a multivariate logistic regression analysis, the duration of active acromegaly was the only risk factor significantly correlated with the occurrence of fractures (odds ratio 1.1, confidence interval 1.04-1.6). CONCLUSIONS: This study reports for the first time a high prevalence of osteoporotic vertebral fractures in an unselected acromegalic male population generally considered at low risk of osteoporosis, suggesting that complicated osteoporosis is an important comorbidity of acromegaly.     

Osteoporosis in hemochromatosis: iron excess, gonadal deficiency, or other factors?

STUDY OBJECTIVE: To define the prevalence, severity, type and pathogenesis of osteopenia in idiopathic hemochromatosis. DESIGN: Prospective study conducted over 18 months. SETTING: Tertiary care center. SUBJECTS: Twenty-two men with idiopathic hemochromatosis and 20 age-matched controls. There were 5 hypogonadal patients, 9 eugonadal nonvenesected patients, and 8 eugonadal venesected patients. MEASUREMENTS AND MAIN RESULTS: All patients and controls were evaluated by spinal radiography, spinal and forearm bone mineral density estimations, dynamic skeletal histomorphometry, and serum biochemistry. Ten patients (45%; 95% CI, 24% to 68%) had osteoporosis as defined by spinal and forearm bone density measurements. Trabecular bone volumes were significantly reduced in the patients (the difference in means between patients and age-matched controls was 3.9%; CI, 1.3% to 6.7%). No patient had osteomalacia. Hypogonadal men had lower bone mass measurements than eugonadal men (radial bone density: beta coefficient = -20.5; CI, -29.2 to -11.8; trabecular bone volume: beta coefficient = -7.1; CI, -10.8 to -3.3). Osteoid and osteoblastic surfaces and bone formation rates were significantly greater in the eugonadal venesected compared with the eugonadal nonvenesected persons (P less than 0.05 for all measurements). CONCLUSIONS: A significant decrease in bone density is seen in idiopathic hemochromatosis, particularly when hypogonadism is present. Low serum free-testosterone concentrations rather than the calciotrophic hormones determine bone mass in this condition.     

Spinal volumetric trabecular bone mass in acromegalic patients: a longitudinal study

Objective  Data on trabecular bone mass in acromegaly are controversial. All the studies are cross-sectional and bone mineral density (BMD) has been evaluated largely by dual X-ray absorptiometry (DXA), which is influenced by bone enlargement. In this study we assessed in acromegalic patients the effects overtime of GH excess on trabecular bone mass measured by single-energy quantitative computed tomography (QCT) which is not influenced by bone size.
Design  Longitudinal retrospective study.
Patients  A total of 46 acromegalic patients followed-up for 48 months (median), subdivided into four groups: group A (eugonadal patients with active disease: n  = 13), group B (hypogonadal patients with active disease; n  = 9), group C (eugonadal patients with controlled disease; n  = 10), group D (hypogonadal patients with controlled disease; n  = 14).
Measurements  Serum GH and IGF-I levels, spinal trabecular BMD, and vertebral fractures were evaluated in all patients. BMD variations were reported as change (Δ) in Z -values (Z-QCT) measured at baseline and end of follow-up per year (Δ Z-QCT).
Results  Δ Z-QCT was greater in group A vs. group B and D ( P = 0·002 and P  = 0·0001, respectively) and in group C vs. group D ( P = 0·009). Multivariate regression analysis showed that hypogonadal status (β = –0·69; P  = 0·001) and baseline duration of hypogonadism (β = 0·44; P  = 0·02) but not baseline duration of acromegaly, length of follow-up and disease activity, were significantly associated with Δ Z-QCT.
Conclusions  This longitudinal study suggests that the effect of chronic GH excess on spinal trabecular bone mass seems to be anabolic in active eugonadal patients but not in hypogonadal ones.     

Cardiac hypertrophy and function in asymptomatic acromegaly.

Heart disease frequently occurs in advanced acromegaly. In order to investigate cardiac mass and function in acromegaly in the absence of obvious cardiac disease, we performed Doppler echocardiography in 15 asymptomatic acromegalic patients (six of them had systemic hypertension). The data were compared with those of a group of 10 age-matched controls. Left ventricular mass index (LVMI) was increased in acromegaly (110 +/- 32 vs 32 +/- 12 g m-2, P = 0.02), but shortening fraction and systolic time intervals did not differ. Mitral EF slope was decreased (80 +/- 21 vs 101 +/- 30 mms-1, P less than 0.02), while the duration of the isovolumic relaxation period (IRP) was increased (92 +/- 13 vs 69 +/- 16 ms, P less than 0.01). Hypertensive acromegalic patients (n = 6) had a higher LVMI than normotensive acromegalic patients (n = 9) (133 +/- 27 vs 94 +/- 24 g m-2, P = 0.02) and this was confirmed by a meta-analysis of data in the literature: the prevalence of hypertrophy was 76% in the presence of hypertension vs 50% in its absence, P less than 0.002. IRP was prolonged in normotensive acromegalic patients vs normal controls (90 +/- 11 vs 69 +/- 16 ms, P less than 0.01). In conclusion, subclinical cardiac abnormalities occur frequently in acromegaly in the absence of obvious heart disease, and hypertrophy is observed in asymptomatic hypertensive acromegaly. Moreover, diastolic abnormalities are found in asymptomatic acromegaly and could be caused by several heart-related factors.     

Factors associated with bone metabolism in acromegalic patients: hypogonadism and female gender.

The purpose of the study was to determine the factors associated with bone metabolism in acromegalic patients. Thirty three patients with acromegaly who had been followed on a regular basis in the endocrinology clinic were enrolled for the study. Among the factors acting upon bone metabolism, age, gender, body mass index (BMI), duration and activity of the disease, length of remission, treatment modalities and functional status of the pituitary were evaluated. Their influences on the determinants of bone remodelling and bone mineral density (BMD) were tried to be elucidated. The median age of the 33 acromegalics (19 females, 14 males) was 39.73 +/- 10.1 years. Twenty-three patients (9 males and 14 females) were eugonadal. Ten patients had been diagnosed with history of at least one year of untreated hypogonadism (5 males and 5 females; for 1 - 10 years). The BMD values of the lumbar vertebrae, the femur and the radius were correlated with each other. Patients were grouped according to their T-scores as decreased, normal, and increased BMD. Groups were similar with regard to age, BMI, gender, duration of disease, and remission, GH, IGF-1, IGFBP-3 levels, markers of bone turnover. Presence of hypogonadism and duration of hypogonadism revealed statistically significant difference among the 3 groups (p = 0.005 and p = 0.035, respectively). Hypogonadal acromegalic patients had decreased BMD compared to eugonadal acromegalics and healthy population while the eugonadal female acromegalic patients revealed increased BMD of lumbar vertebrae, femur, and distal radius compared to the sex-matched healthy population.     

Body composition and skeletal metabolism following pituitary irradiation in acromegaly

The change in body composition in acromegaly that resulted from pituitary irradiation was examined using the technic of total body neutron activation analysis. Before treatment, increased ratios of total body P:Ca, P:K and Na:K were noted. After pituitary irradiation, the total body levels of P, Na and K were reduced in a proportion that indicated restoration of body composition towards normal. Skeletal mass (total body calcium) decreased into the range observed in osteoporosis in several patients. Trabecular bone mass, as reflected by the Singh Index, was consistently reduced, and two patients had vertebral compression fractures. Local bone mass as determined by photon absorptiometry was reduced when the values were normalized for age, sex and body size.It is postulated that in untreated acromegaly there is differential bone remodelling with an increase in cortical bone accompanied by a reduced trabecular bone mass. When reduction of hGH levels is accomplished with treatment, cortical apposition may decrease. Since the increased cortical bone mass probably aids in preventing vertebral compression fractures, the treated acromegalic patient may incur an increased risk of fractures. This risk may be increased further by the hypogonadism which may arise secondary to pituitary irradiation or surgery. It would be prudent to ensure that the hypogonadal acromegalic patient receives an adequate calcium intake and sex hormone replacement therapy.     

Acromegalic osteopathy

Acromegalic osteopathy is an emerging complication of acromegaly characterized by increase in bone turnover, deterioration in bone microarchitecture and high risk of vertebral fractures. Vertebral fractures, as diagnosed by a radiological and morphometric approach, occur in about one-third of acromegaly patients in close relationship with duration of active disease. However, the prediction of vertebral fractures in this clinical setting is still a matter of uncertainty, since the pathogenesis of acromegalic osteopathy is multifactorial and fractures may occur even in presence of normal bone mineral density. In this narrative article, we summarize the pathophysiology and clinical aspects of acromegalic osteopathy.     

Hypogonadism in patients with acromegaly: data from the multi-centre acromegaly registry pilot study

OBJECTIVE: Because acromegaly is an uncommon disorder, epidemiological data regarding the demographics of the disease such as the prevalence of hypogonadism have been limited. In order to derive clinical and epidemiological information, including underlying hormonal factors, regarding hypogonadism in patients with acromegaly, we performed a pilot study designed to develop a multi-centre acromegaly patient registry. DESIGN AND MEASUREMENTS: Medical records of patients with acromegaly seen between 1976 and 1996 at three Institutions were reviewed, and data were entered into a database using a secure internet website. Hypogonadism was defined as amenorrhoea in women and testosterone deficiency in men. Subanalysis was performed in patients with microadenomas and women less than 50 years of age, to include women of reproductive age. RESULTS: Information was available on 363 patients, of whom 54% were women. The mean age at diagnosis was 41 +/- 13 years. In subjects less than 50 years of age, hypogonadism was present in 59%. Hyperprolactinaemia was present in 45% and 21% of hypogonadal and eugonadal patients of reproductive age, respectively (P = 0.0003). GH levels were higher in patients with hypogonadism (P = 0.03). In patients < 50 years of age with microadenomas, hypogonadism was present in nine of the 22 (41%) patients, including 55% of the women and 27% of the men (P = ns). Hyperprolactinaemia was present in three of the 10 and four of the 14 of microadenoma patients with hypogonadism and eugonadism, respectively. CONCLUSION: We developed a web-based acromegaly patient registry and used it to show that hypogonadism is a frequent consequence of acromegaly, even in patients with microadenomas, who are not at risk from hypopituitarism due to local mass effects. We also demonstrated that prolactin and GH hypersecretion contribute to the pathogenesis of hypogonadism in acromegaly, and that hypogonadism may occur in microadenoma patients even in the absence of hyperprolactinaemia.     

Serum GH and IGF-I are significant determinants of bone turnover but not bone mineral density in active acromegaly: a prospective study of more than 70 consecutive patients

OBJECTIVE: Acromegaly is characterized by a persistent hypersecretion of GH and provides information on long-term effects of GH on bone metabolism. The aim of this study was to examine the effect of gonadal status and disease activity on bone metabolism in active acromegaly. METHODS: Seventy-three consecutive patients with active acromegaly: 40 women and 33 men (50 +/- 13 (mean +/- s.d.) and 49 +/- 10 years respectively) were evaluated and compared with age-, sex-, and body mass index (BMI)-matched controls by X-ray absorptiometry and biochemical analysis (markers of disease activity and bone turnover). RESULTS: We found that bone turnover, as evaluated by biochemical bone markers, is coupled and markedly increased in relation to disease activity in active acromegaly. Acromegalic women, but not men, were characterized by an increased bone area and slightly decreased bone mineral content resulting in significantly decreased bone mineral density (BMD) in the ultradistal radius, proximal radius, and total body. No differences in bone turnover or BMD were found between eu-and hypogonadal subjects. Multivariate analysis identified age, BMI, and gender as independent predictors of total BMD in acromegaly. CONCLUSION: Our study demonstrates a decreased total body BMD in women, not men, with active acromegaly, regardless of gonadal status or disease activity. Bone turnover is markedly increased in relation to disease activity, possibly counteracting the anabolic effects of excess GH/IGF-I in these subjects. We suggest more focus on biomechanical analyses when investigating endocrine disorders affecting bone size and distribution between compartments.     

A therapeutic dilemma: suppressive doses of thyroxine significantly reduce bone mineral measurements in both premenopausal and postmenopausal women with thyroid carcinoma

We measured lumbar spine, femoral neck, and forearm bone mineral (BMD) in 24 women (14 premenopausal and 10 postmenopausal) who had been treated with total thyroidectomy and 131 Iodine ablation therapy for nonanaplastic thyroid carcinoma and 24 case controls. At the time of the study, all patients were free of cancer (negative 131 Iodine whole body scan and serum thyroglobulin levels less than 0.3 micrograms/L) and all were receiving doses of T4 sufficiently high to prevent a rise in a serum thyroid-stimulating hormone concentration after an iv bolus of TRH. Femoral neck BMD were significantly reduced in both the premenopausal women (89 +/- 3.8% of case controls, 95% CI, 81 to 98) and postmenopausal women (77 +/- 3.9% of case controls; 95% CI, 68 to 86) receiving T4. Lumbar spine BMD and forearm BMD were unaffected in the premenopausal women, but significantly reduced in the postmenopausal women receiving T4 (lumbar spine BMD = 84 +/- 6.2% of case controls; 95% CI, 70 to 98 and forearm BMD = 89 +/- 5.6% of case controls; 95% CI, 76 to 101). Serum bone Gla-protein, a marker of bone turnover, was significantly increased in both the premenopausal and the postmenopausal women receiving T4 compared to case controls (P less than 0.001 for the difference between patient groups and controls). Whereas the cumulative dose of T4 was highly correlated with the femoral neck BMD in the premenopausal patients (r = 0.528; P less than 0.05); the presence of hypogonadism was the main determinant of the lumbar spine and forearm BMD. This data confirms that premenopausal and postmenopausal women receiving suppressive doses of T4 for thyroid carcinoma have diminished bone mineral measurements and are at risk for osteoporosis.     

Serum concentrations of somatomedins and growth hormone in relation to bone metabolism in acromegaly and thyroid dysfunction

Many hormones are involved in the complex process of formation and resorption of bone. However, only somatomedin is found to directly stimulate cell replication and collagen synthesis in bone. This study was undertaken to examine a possible regulatory role of somatomedin in mediating the effects of growth hormone and thyroid hormones on bone metabolism. Bone metabolism and concentrations of somatomedins and growth hormones were studied in 17 acromegalic, 15 thyrotoxic and 14 hypothyroid patients, before and during treatment. During treatment of acromegalic and thyrotoxic patients parameters of bone turnover, both formation and resorption, decreased parallel to the decrease in concentration of somatomedin. During treatment of hypothyroid patients parameters of bone turnover increased. A positive correlation was found in acromegalic patients between changes in somatomedins and parameters of bone resorption (R = 0.82, P less than 0.01) as well as bone formation (R = 0.63, P less than 0.05) and in thyrotoxic patients between changes in somatomedin and bone resorption (R = 0.87, P less than 0.05). These data suggest that somatomedin may indeed play a role in the regulation of bone turnover. In addition, secondary effects on growth hormone concentrations were observed.     

Long-term maintenance of the anabolic effects of GH on the skeleton in successfully treated patients with acromegaly

INTRODUCTION: The anabolic actions of growth hormone (GH) are well documented. In acromegaly, the skeletal effects of chronic GH excess have been mainly addressed by evaluating bone mineral density (BMD). Most data were obtained in patients with active acromegaly, and apparently high or normal BMD was observed in the absence of hypogonadism. Data on BMD are not available after successful treatment of acromegaly. Whether the positive effect of GH excess on bone mass is maintained in the long term after clinical and biochemical cure of acromegaly remains to be established. PATIENTS AND METHODS: In a cross-sectional study design, lumbar spine and femoral neck BMD was measured in 79 acromegalic patients cured or well controlled on octreotide treatment (45 male and 34 female patients; mean age 57+/-1 years). Successful treatment (by surgery, radiotherapy and/or use of octreotide) was defined as normal age-adjusted IGF-I. Mean time after biochemical remission was 10.2+/-7 years. RESULTS: Normal or increased BMD was observed at the femoral neck and lumbar spine in both men and women in remission after treatment for acromegaly. Similar results were obtained in patients in remission for 5 years or longer. Osteoporosis was present in 15% of the patients, with similar prevalence in men and women. There was no relationship between BMD and duration or severity of GH excess before treatment, gonadal status and presence of pituitary hormone deficiencies. Pituitary irradiation was a strong negative predictor of bone mass at the femoral neck. Long-term bone loss was observed only at the femoral neck. CONCLUSION: Our data suggest that the anabolic effect of GH on trabecular and cortical bone remains demonstrable after remission of acromegaly, although it may not be maintained at cortical sites in the long term. In the present study, the lack of effect of gonadal status on BMD may be explained by the presence of only mild hypogonadism and by our policy of prompt hormonal replacement therapy for severe hypogonadism. The negative effect of pituitary irradiation on femoral neck BMD remains intriguing, although it is probably related to some degree of the diminished GH secretion frequently observed after this form of treatment.     

Changes in bone metabolism during treatment of acromegaly

Bone metabolism was studied in 17 acromegalic patients, who responded to either medical treatment with bromocriptine (12 patients), or to transsphenoidal surgery (5 patients). Parameters of bone turnover decreased, e.g. serum acid phosphatase (9.2 +/- 0.7 vs 8.1 +/- 0.6 U/l, P less than 0.05) and the ratio of hydroxyproline/creatinine (33.6 +/- 4.4 vs 18.3 +/- 2.0, P less than 0.01) in the urine. No changes were observed in parathyroid function or concentrations of calcitonin. Serum 1,25-dihydroxycholecalciferol decreased (32.6 +/- 3.6 vs 20.6 +/- 1.8 ng/l, P less than 0.01) and 24,25-dihydroxycholecalciferol increased (4.3 +/- 0.6 vs 6.7 +/- 1.0 micrograms/l, P less than 0.05). No correlation between the percentual changes in serum growth hormone levels and 1,25-dihydroxycholecalciferol was found, suggesting an indirect effect of growth hormone on the renal 25-hydroxycholecalciferol-1-alpha-hydroxylase. The possible mechanisms involved are discussed, including the effects of growth hormone and somatomedin on bone.     

Effects of normalization of GH hypersecretion on lipoprotein(a) and other lipoprotein serum levels in acromegaly

BACKGROUND & AIMS: Lipoprotein(a) has been recognized as an important risk factor for cardiovascular disease. Lipoprotein(a) has been found to be elevated in sera of acromegalic patients, possibly contributing to the increased incidence of coronary heart disease found in these patients. In the present study we sought to determine the effects of GH hormonal status on lipoprotein(a) and other lipid parameters, including lipoprotein lipase (LPL) activity. DESIGN: Cross-sectional study. PATIENTS: Twenty acromegalic patients, with either active (n = 12) or controlled (n = 8) acromegaly, were studied. Twenty-nine healthy subjects served as control group for serum lipid measurements. MEASUREMENTS: Serum GH, IGF-1, IGF binding protein-3 (IGFBP-3) and insulin levels were measured in patients. Insulin resistance was measured by the homeostatic model assessment (HOMA). Plasma total cholesterol, triglycerides, HDL-lipids, apolipoproteins A-I and B, lipoprotein(a) and lipoprotein lipase activity were also measured. RESULTS: The highest lipoprotein(a) levels were observed in patients with active acromegaly, followed by patients with controlled acromegaly, whose lipoprotein(a) concentrations were still significantly higher than those of the control group (means +/- SEM: active acromegaly, 0.67+/-0.13 g/l; controlled acromegaly, 0.41+/-0.12 g/l; controls 0.17+/-0.02 g/l; P<0.05). There were no differences in other lipid and lipoprotein values among the groups. In patients, significant correlations were observed between lipoprotein(a) and basal GH levels (r = 0.56, P<0.02), mean GH levels (r = 0.48, P<0.05) and with insulin resistance estimated by HOMA (r = 0.62, P<0.01). No correlations were found between lipoprotein(a) and IGF-1 or IGFBP-3 levels. CONCLUSIONS: Our present results demonstrate that both active acromegalic patients and those with controlled disease have elevated serum lipoprotein(a) concentrations. The findings might suggest that the present biochemical criteria for cure of acromegaly are not strict enough to result in the normalization of all the undesirable metabolic changes found in this disease, and also that significant cardiovascular risk may persist despite successful treatment of acromegaly.     

The GH-releasing hormone (GHRH) test in acromegaly before and after adenomectomy

The GHRH test may represent a new tool in the study of GH dynamics in acromegaly. GH responsiveness to GHRH 1-40 (50 micrograms iv) has been studied in 21 acromegalic patients. Nineteen out of 21 had active disease. Five patients were also studied 1-12 months after neurosurgery. Two apparently cured acromegalics were studied 1-2 yr after surgery. GH secretion has been evaluated in all patients by means of TRH, bromocriptine and insulin hypoglycemia tests, too. GH response to GHRH has also been performed in 14 normal subjects. In acromegaly, GH responses after GHRH (p less than 0.01 vs placebo) were variable. The GH peak ranged from 8 to 445 ng/ml in patients with active disease. Maximum GH increase after GHRH (calculated as peak/basal value ratio) was significantly reduced in acromegaly (2.9 +/- 0.5 ng/ml; mean +/- SE) in comparison to controls (34.1 +/- 10.9 ng/ml; p less than 0.01). No significant differences in GH pattern after GHRH were found between untreated and previously treated patients with active disease. A significant correlation was found between GH basal levels and GH incremental area (p less than 0.05) and between GH basal and peak levels (p less than 0.01) after GHRH. A significant increase in PRL secretion was observed in acromegalic patients after GHRH (p less than 0.01 vs placebo). No discernable variation was found in the other pituitary hormones pattern after the peptide administration. A positive correlation was observed between GH increase after GHRH and insulin hypoglycemia (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Improvement of intrinsic myocardial contractility and cardiac fibrosis degree in acromegalic patients treated with somatostatin analogues: a prospective study

BACKGROUND: Acromegalic patients have increased left ventricular (LV) mass (M) and impaired diastolic function. AIM: Using ultrasonic cardiac tissue characterization, we evaluated the early changes in cardiac fibrosis (IBS) and intrinsic myocardial contractility (CVI) as well as their reversibility after treatment with somatostatin analogues (SMSA) in patients with acromegaly. PATIENTS AND METHODS: Twenty-two acromegalic patients with active untreated disease (Acro(UNTR)) underwent conventional Doppler echocardiography and integrated backscattering; 25 healthy subjects (controls) and eight patients with acromegaly in remission after pituitary adenomectomy (Acro(REM)) served as controls. RESULTS: As expected, Acro(UNTR) at baseline had higher LVM than controls or Acro(REM) (P < 0.001); LVM reduced in acromegalic patients after SMSA (P < 0.005 vs. baseline) while LV ejection fraction did not change. LV diastolic function was reduced in all acromegalic patients, either at baseline or after SMSA therapy (E/A ratio, 0.96 +/- 0.3 and 1.1 +/- 0.3, respectively, P < 0.002 vs. controls, 1.6 +/- 0.3). CVI was reduced in Acro(UNTR) (14.3 +/- 5.8%, P < 0.003 vs. controls, 28.7 +/- 7.5%) and greatly improved after SMSA (22.5 +/- 4.5%, P < 0.003 vs. baseline). Cardiac fibrosis was increased in Acro(UNTR) (IBS(MSI), 53.7 +/- 5.3%P < 0.002 vs. controls) and reduced after SMSA (43.7 +/- 4.2%P < 0.002 vs. baseline) albeit not reaching values observed in controls. More importantly, five of 22 (23%) Acro(UNTR) patients had normal LVM, but increased cardiac fibrosis as revealed by back scattering. IBS values and CVI% were related with serum GH and IGF-1 (P < 0.0001) levels, and the estimated duration of disease (P < 0.005). CONCLUSIONS: The present study demonstrated that active acromegalic patients had early impairment of systolic function and increased cardiac fibrosis; increased fibrosis may precede LV hypertrophy; these changes are related to the activity of disease and might improve during treatment with SMSA.     

Association of hypogonadism and estradiol levels with bone mineral density in elderly men from the Framingham study

BACKGROUND: Both hypogonadism and low estrogen levels adversely affect bone health in young men. In elderly men, who are at greatest risk for osteoporotic fracture, the influence of hypogonadism on bone mineral density remains unclear, as does the relative effect of estrogen status compared to hypogonadism. OBJECTIVE: To examine the relation of hypogonadism and estrogen status to bone mineral density in elderly men. DESIGN: Community-based, prospective cohort study. SETTING: Framingham, Massachusetts. PATIENTS: Male participants of the Framingham Study. MEASUREMENTS: Total testosterone, total estradiol, and luteinizing hormone were measured in participants at all four biennial examinations from 1981 to 1989. Values from at least three of four examinations were averaged. Hypogonadism was defined as a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) or a mean luteinizing hormone level of 20 IU/L or greater. An alternate definition of hypogonadism based only on a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) was also used. In 1988-1989, bone mineral density was measured at the proximal femur (femoral neck, Ward triangle, and trochanter) and lumbar spine by using dual-photon absorptiometry and at the radial shaft by using single-photon absorptiometry. The association of hypogonadism with bone mineral density was examined with adjustment for confounders, including estradiol levels. A similar model that adjusted for hypogonadism was used to examine the association of estradiol level (ranked as quartiles) with bone mineral density. RESULTS: Of 448 men with bone mineral density measurements, 405 had evaluable hormone levels (mean age, 75.7 years [range, 68 to 96 years]); 71 (17.5%) of the 405 men were hypogonadal. Bone mineral density at any site did not significantly differ in hypogonadal men compared with eugonadal men (for example, bone mineral density at the femoral neck was 0.89 g/cm(2) vs. 0.87 g/cm(2), respectively; P > 0.2), even when alternate definitions of hypogonadism were used. In contrast, compared with the lowest estradiol quartile, men with higher estradiol levels had greater mean bone mineral density at all sites (for example, bone mineral density at the femoral neck was 0.84 g/cm(2), 0.88 g/cm(2), 0.86 g/cm(2), and 0.91 g/cm(2) from the lowest to the highest estradiol quartile; P for trend = 0.002). The difference in mean bone mineral density between men in the lowest and those in the highest estradiol quartile levels was similar to the effect of 10 years of aging on bone mineral density. CONCLUSIONS: In elderly men, hypogonadism related to aging has little influence on bone mineral density, but serum estradiol levels have a strong and positive association with bone mineral density.     

Muscle sympathetic nerve activity in patients with acromegaly

Muscle sympathetic nerve activity was measured in nine acromegalic patients (age, 35 +/- 4 yr; body mass index, 28 +/- 2 kg/m2) and eight healthy subjects (age, 32 +/- 3 yr; body mass index, 25 +/- 2 kg/m2) by combining the forearm arterial-venous difference technique with the tracer method [infusion of tritiated norepinephrine (NE)]. Muscle NE release was quantified both at rest and during physiological hyperinsulinemia while maintaining euglycemia (approximately 90 mg/dL) by means of the euglycemic clamp. Arterial plasma NE was similar in the two groups at rest (197 +/- 28 and 200 +/- 27 pg/mL (-1) and slightly increased during insulin infusion. Forearm NE release was 2.33 +/- 0.55 ng x liter(-1) x min(-1) in healthy subjects and 2.67 +/- 0.61 ng x liter(-1) x min(-1) in acromegalic subjects in the basal state and increased to a similar extent during insulin infusion in both groups (3.13 +/- 0.71 and 3.32 +/- 0.75 ng x L(-1) x min(-1), P < 0.05 vs. basal), indicating a normal stimulatory effect of insulin on muscle sympathetic activity. In contrast, insulin-stimulated forearm glucose uptake was markedly lower in acromegalic patients (2.3 +/- 0.4 mg x L(-1) x min(-1)) than in control subjects (7.9 +/- 1.3 mg x L(-1) x min(-1), P < 0.001), indicating the presence of severe insulin resistance involving glucose metabolism. Our data demonstrate that patients with long-term acromegaly have normal sympathetic activity in the skeletal muscle in the basal, postabsorptive state and normal increments in NE spillover in response to the sympatho-excitatory effect of insulin. Thus, the presence of severe insulin resistance in acromegaly is not accounted for by adrenergic mechanisms.     

Effect of gender and gonadal status on the long-term response to somatostatin analogue treatment in acromegaly

:GH and IGF-I secretion is related to gender and age. OBJECTIVE: To evaluate the impact of gender and gonadal status on the long-term sensitivity to the somatostatin analogues depot octreotide long-acting release (OCT-LAR) and lanreotide (LAN). PATIENTS: Seventy-three patients with active acromegaly (37 women, median age 34 years; 36 men, median age 38 years) who had not previously been treated with somatostatin analogues were studied: 24 women and 23 men were newly diagnosed; 22 men (61.1%) and 17 women (45.9%) had hypogonadism (P=0.28). Exclusion criteria were age >45 years, follow-up less than 12 months, mixed GH/PRL-secreting adenomas. Study design Observational, analytical, retrospective. Outcome measures (1) Disease control measured as serum GH< 2.5 microg/l and IGF-I normal for age and gender; (2) reduction in tumour volume graded as absent (< 25%), mild (25-50%) and notable (>50%). Results Basal GH, but not IGF-I, levels were higher in women than in men both in the entire series and in 'de novo' patients (97.8+/- 42.2 vs. 71.1+/- 32.6 microg/l, P=0.021). After 12 and 24 months of treatment, respectively, disease control was achieved similarly in men (57.1 and 86.7%) and women (48.6 and 86.7%). Hypogonadal men had longer disease duration than eugonadal men (P=0.022), without any difference in the other parameters. No difference was found between eugonadal and hypogonadal women. Eugonadal men had a smaller tumour volume at baseline than eugonadal women (1396+/- 794 vs. 2896+/- 2871 mm(3), P=0.025). In men undergoing testosterone replacement and withdrawal, there was no change in GH and IGF-I levels after 12 and 24 months of treatment with either LAR or LAN. In the seven women receiving oestro-progestinic replacement, after 24 months of LAR or LAN treatment GH levels were higher during replacement than at withdrawal and IGF-I levels were lower during replacement than withdrawal. Tumour volume decreased significantly in both women and men without any difference between them: the percentage tumour shrinkage in men and women was similar either after 12 (34.4+/-24.4 vs. 40.7+/-22.5%, P=0.38) or 24 months of treatment (58.5+/- 17.4 vs. 56.1+/- 23.6%, P=0.75). Similarly, there was no difference in tumour volume between hypogonadal and eugonadal women and men. CONCLUSIONS: The results of this study demonstrate that long-term responsiveness to OCT-LAR is similar in women and men. Care should be taken in women with acromegaly and hypogonadism treated with somatostatin analogues and oral oestro-progestinic as in this case GH levels are higher while IGF-I levels are lower than after the somatostatin analogues alone.