Dysgénésies gonadiques et métabolisme osseux

Gonadal dysgenesis is defined as congenital hypogonadism related to abnormalities of the sex chromosomes. Because sex steroids play a central role in the acquisition and maintenance of bone mass, studies have been done to investigate bone status in patients with gonadal dysgenesis, particularly Turner's syndrome and Klinefelter's syndrome, which are the two most common types. The severe estrogen deficiency characteristic of Turner's syndrome (44, X0) is associated with a significant bone mass decrease ascribable to increased bone turnover, as shown by histological studies and assays of bone turnover markers. Estrogen therapy is followed by a significant bone mass gain and a return to normal of bone turnover markers, suggesting that it is the estrogen deficiency rather than the chromosomal abnormality that causes the bone mass deficiency, although abnormalities in the renal metabolism of vitamin D have been reported. Combined therapy with estrogens and growth hormone seems beneficial during the prepubertal period. In Klinefelter's syndrome (47XXY),  serum testosterone levels are at the lower end of the normal range and dihydrotestosterone levels are low. Histological studies show depressed osteoblast function and a decrease in 5-alpha-reductase activity responsible for partial tissue resistance to androgens. Assays of bone turnover markers show evidence of increased bone turnover. The bone deficiency is most marked at the femoral neck and seems correlated with serum testosterone and estradiol levels. Androgen therapy has favorable effects on the bone only if it is started before puberty. Recent data suggest that estrogens may contribute to the development of demineralization in KS and that bisphosphonate therapy may be beneficial.     

A longitudinal study of the effect of subcutaneous estrogen replacement on bone in young women with Turner's syndrome.

It is desirable that young women with primary ovarian failure achieve normal peak bone mass to reduce the subsequent risk of osteoporosis, and that there are management strategies to replace bone that is already lost. While estrogen (E2) is generally considered to prevent bone loss by suppressing bone resorption, it is now recognized that estrogen also exerts an anabolic effect on the human skeleton. In this study, we tested whether estrogen could increase bone mass in women with primary ovarian failure. We studied the mechanism underlying this by analyzing biochemical markers of bone turnover and iliac crest biopsy specimens obtained before and 3 years after E2 replacement. Twenty-one women with Turner's syndrome, aged 20-40 years, were studied. The T scores of bone mineral density at lumbar spine and proximal femur at baseline were -1.4 and -1.1, respectively. Hormone replacement was given as subcutaneous E2 implants (50 mg every 6 months) with oral medroxy progesterone. Serum E2 levels increased incrementally from 87.5 pM at baseline to 323, 506, 647, and 713 pM after 6 months and 1, 2, and 3 years of hormone replacement therapy (HRT), respectively. The bone mineral density at the lumbar spine and proximal femur increased after 3 years to T scores of -0.2 and -0.4, respectively. The cancellous bone volume increased significantly from 13.4% to 18.8%. There was a decrease in activation frequency, but the active formation period was increased by HRT. There was a significant increase in the wall thickness from 33.4 microm at baseline to 40.9 microm after 3 years of HRT, reflecting an increase in bone formed at individual remodeling units. Although there was an early increase in biochemical markers of bone formation, these declined thereafter. Our results show that estrogen is capable of exerting an anabolic effect in the skeleton of young women with Turner's syndrome and low bone mass.     

Skeletal size and bone mineral content in Turner's syndrome: Relation to karyotype,estrogen treatment,physical fitness,and bone turnover

Summary Bone mineral content (BMC), bone mineral density, and metacarpal dimensions were studied in 50 women with Turner's syndrome aged 21–45 years in relation to karyotype, estrogen treatment, physical fitness, and biochemical markers of bone turnover. No differences were found between the 25 women with karyotype 45,X and women with other karyotypes. Forty-six women had received estrogen. Significant partial correlations were found between bone mineral density of the forearm and duration of estrogen treatment and physical fitness. BMC of the lumbar spine corrected for vertebral height (BMC(C)_spine) was directly correlated with duration of estrogen treatment and height, marginally correlated with physical fitness, and inversely correlated with age. Outer metacarpal width was positively correlated with duration of estrogen treatment, age at initiation of therapy, and body weight. The diameter of medullary space showed negative correlation with physical fitness and height, and positive correlation with age at initiation of estrogen treatment. Cortical thickness was positively correlated with duration of estrogen treatment, physical fitness, and height. No convincing effects of estrogen could be demonstrated in women below the age of 30. Above the age of 30, all bone mineral measurements were markedly elevated in women treated for longer than the average of this age group. BMC(C)_spine was inversely correlated with biochemical markers of bone formation. Our results demonstrate that estrogen treatment and physical fitness are important determinants of bone mineral status in Turner's syndrome and add to the evidence that estrogen treatment increases BMC in Turner's syndrome.     

Estrogen Deficiency is a Potential Cause for Osteopenia in Adult Male Patients with Noonan's Syndrome

Osteopenia is frequently observed in patients with Turner's syndrome. By contrast, there is no report concerning bone metabolism in patients with Noonan's syndrome which comprises Turner's phenotypic characteristics without any sex chromosome abnormalities. In the present investigation, we determined bone mineral density (BMD) as well as serum and urine indices of bone turnover in two male patients with Noonan's syndrome. Both patients showed remarkably decreased BMD, measured at two sites on the lumbar spine (L2-L4) and the distal end of the radius using dual energy X-ray absorptiometry (DXA). Urinary pyridinoline (PYD) and deoxypyridinoline (DPD) concentrations were significantly elevated in both patients, and serum osteocalcin and carboxyterminal propeptide of type I procollagen (PICP) concentrations were elevated in one patient. Surprisingly, both patients had a low level of serum 17β-estradiol compared with control males, whereas they had normal levels of serum testosterone and dihydrotestosterone. Conjugated estrogens (Premarin 0.625 mg/day) were continued to be administered to these patients, followed up for 12 months. Urinary PYD and DPD concentrations gradually decreased, followed by an increase in their BMD. This is the first report that male patients with Noonan's syndrome showed osteopenia associated with increased bone resorption. Our data indicate that hypoestrogenism plays a potentially significant role in the abnormal bone metabolism in these patients. Received: 11 May 1999 / Accepted: 30 September 1999     

Bone demineralization, biochemical indices of bone remodeling, and estrogen replacement therapy in adults with Turner's syndrome

The study centered on a controversy about whether long-term estrogen replacement therapy may ameliorate the osteoporosis seen in patients with Turner's syndrome. This study comprised 26 adult patients with Turner's syndrome (9 treated and 17 untreated or insufficiently treated) and 12 adult women with pure gonadal dysgenesis (8 untreated and 4 treated). A low bone density below -2 standard deviations from the age- and sex-matched predicted normal mean was documented by dual-photon absorptiometry of the lumbar spine in all the untreated and insufficiently treated patients, but only in 6 treated patients. The biochemical indices of bone resorption (urinary hydroxyproline excretion and plasma tartrate-resistant acid phosphatase activity), as well as osteoblastic function (serum osteocalcin and bone alkaline phosphatase isoenzyme), were significantly increased in untreated and insufficiently treated patients compared with treated patients. A significant negative correlation was found between biochemically documented osteoresorption and spinal bone mineral density corrected for age of the patients. Significant positive correlations were found between serum osteocalcin and bone alkaline phosphatase isoenzyme and between biochemical indices of bone resorption and formation. Although in the patients there was an evidence of a high bone remodeling rate, the rate of bone mass loss seemed to be low, comparable with that seen in oophorectomized women who had already passed their accelerated phase of bone loss. The results indicate that long-term hormonal replacement therapy is justified in gonadal dysgenesis, regardless of the karyotype of the patient, to prevent further bone mass loss.     

Loss of bone mass in patients with Klinefelter's syndrome despite sufficient testosterone replacement

To determine whether testosterone replacement therapy reverses the detrimental effects of hypogonadism on bone density, we measured the total body, lumbar spine and proximal femur bone mineral density (BMD) by dual-energy X-ray absorptiometry in 14 patients with Klinefelter's syndrome on long-term testosterone replacement therapy and compared the results with 14 age- and sex-matched normal controls. Seven of the patients were receiving oral testosterone undecanoate thrice daily (240 mg/day) and the others were having intramuscular testosterone enanthate injections once every 3 weeks (250 mg/injection). Their serum testosterone levels were maintained within the normal limits (10–40 nmol/l). We showed that patients on testosterone replacement had decreased amount of bone density in the left femoral neck when compared with the controls (p<0.01). Similar decreases were also observed in the left Ward's triangle (p<0.01) and in the left trochanter (p<0.05). There were no significant differences in the total body and the lumbar spine measurements in these two groups of subjects. No correlation was found between the BMD values of femur and the duration of testosterone treatment in the patients with Klinefelter's syndrome. The type of testosterone treatment was also not associated with significant differences in BMD. In conclusion, sufficient testosterone replacement with currently available methods does not reverse the decrease in bone mass associated with hypogonadism in patients with Klinefelter's syndrome.     

Skeletal effects of long-term estrogen and testosterone replacement treatment in a man with congenital aromatase deficiency: evidences of a priming effect of estrogen for sex steroids action on bone

The relative contribution of each sex steroid (i.e. estrogen and androgen) on bone in men and the relationships among sex steroids and changes in BMD and bone strength are still unknown. A defective BMD of bone tissue is constantly present in men with aromatase deficiency. This study evaluates the effects of different regimens of treatment with sex steroids over 7.3 years follow-up on BMD in an adult man affected by aromatase deficiency and by a concomitant mild hypogonadism, as previously described. The aim of the study is to provide additional data on the relative roles of androgens and estrogens in male bone metabolism. The effects of testosterone (T) treatment alone and estrogen (tE₂) treatment alone as well as the effects of the combined treatment with testosterone and estradiol (T plus tE₂) on areal BMD (aBMD) at dual-energy X-ray absorptiometry (DXA) and the effects of T plus tE₂ on volumetric BMD (vBMD), particular at cortical site, measured by peripheral quantitative computed tomography (pQCT), are investigated. Hormones and markers of bone turnover were monitored during all phases of the study. Treatment with tE₂ normalized serum estradiol, but only the combined treatment with T plus tE₂ normalized both serum estradiol and testosterone. Markers of bone turnover reached a pattern close to normality during T plus tE₂. The aBMD was little modified by T, but increased more during tE₂. T plus tE₂ resulted in a further increase in both aBMD at DXA and vBMD at pQCT. Cortical thickness increased during T plus tE₂ both in radius and tibia. Only the combined treatment led to optimal parameters of aBMD suggesting that testosterone needs estrogens as a permissive factor for a direct androgen anabolic action on bone in men.     

Hypogonadotrophic variant of Klinefelter's syndrome. A case report

A 16-year-old boy with 47,XXY chromosomal complement (Klinefelter's syndrome) presented with delayed puberty and apparent gonadotrophin deficiency. Despite an inadequate growth hormone response to insulin-induced hypoglycaemia and to L-dopa administration, his somatic growth was appropriate for his delay in pubertal development, increasing markedly on testosterone treatment. Patients with Klinefelter's syndrome may have abnormalities of neuro-endocrine regulation.     

Effects of raloxifene, a selective estrogen receptor modulator, on bone turnover markers and serum sex steroid and lipid levels in elderly men.

Several lines of evidence implicate estrogen deficiency as a cause of bone loss in elderly men. Thus, in 50 elderly men (mean age +/- SD, 69.1 +/- 6.0 years), we performed a randomized blinded study to assess the effect of 6 months of treatment with 60 mg/day of raloxifene (a selective estrogen receptor modulator [SERM] that has an agonist effect on bone but is not feminizing) versus placebo on bone turnover markers. The mean changes in bone turnover markers, serum sex steroid, or lipid levels with treatment did not differ between groups. However, changes in urinary cross-linked N-telopeptide of type I collagen (NTX) excretion were related directly to the baseline serum estradiol level in the raloxifene (r = 0.57; p = 0.004) but not in the placebo-treated (r = 0.15; p = 0.485) men (p = 0.015 for the difference between groups). Moreover, the men in whom NTX excretion decreased after raloxifene treatment had significantly lower baseline estradiol levels (mean +/- SEM, 22 +/- 2 pg/ml) than the men in whom urinary NTX excretion didn't change or increased after raloxifene therapy (30 +/- 3 pg/ml; p = 0.03), and no such difference was found in the placebo group. Thus, raloxifene has no significant effect on bone turnover markers or lipid levels in elderly men. However, the association noted between baseline estradiol levels and the change in urine NTX excretion in the raloxifene-treated men suggests that a subset of men with low estradiol levels may respond to raloxifene or other SERMs, and further studies are needed to directly test this possibility.     

Effect of aromatase inhibition on bone metabolism in elderly hypogonadal men

Both estrogens and androgens play important roles in skeletal development and maintenance in men. The relative importance of estrogens and androgens in male bone metabolism, however, remains undefined. Anastrozole is an oral aromatase inhibitor that decreases estrogen production and increases androgen production in men. Currently, anastrozole is being investigated as a potential agent for the treatment of hypogonadism in aging men. Because anastrozole lowers estrogen levels and raises androgen levels, its effect on bone metabolism is difficult to predict. To assess the effects of anastrozole on bone turnover, we randomized 37 elderly (ages 62–74) mildly hypogonadal men (serum testosterone <350 ng/dl) to receive either anastrozole 1 mg daily ( n =12), anastrozole 1 mg twice weekly ( n =11), or daily placebo ( n =14) for 12 weeks. Serum gonadal steroid levels, serum and urine biochemical markers of bone turnover, serum osteoprotegerin, and total body bone mineral density were measured at baseline and week 12. Mean serum levels of total and bioavailable testosterone increased substantially in both treated groups. Specifically, mean ± SD bioavailable testosterone levels increased from 99±31 ng/dl to 207±65 ng/dl in the group receiving 1 mg of anastrozole daily and from 115±37 ng/dl to 178±55 ng/dl in the subjects receiving 1 mg of anastrozole twice weekly ( p <0.001 vs placebo for both groups). Serum estradiol levels decreased modestly in both treated groups (from 26±8 pg/ml to 17±6 pg/ml in the daily treatment group and from 27±8 pg/ml to 17±5 pg/ml in the twice-weekly treatment group, p <0.001 vs placebo for both groups). Despite these hormonal changes, no increases in biochemical markers of bone resorption were observed. Specifically, mean serum N-telopeptide and urinary deoxypyridinoline concentrations remained stable in both treated groups over the 12-week treatment period. Similarly, serum biochemical markers of bone formation (osteocalcin and amino-terminal propeptide of type 1 collagen), serum osteoprotegerin, and total body bone mineral density did not change. These data demonstrate that although short-term administration of anastrozole decreases serum estradiol levels in elderly men with mild hypogonadism, this intervention does not adversely affect bone metabolism over a 12-week period. This lack of an effect may be due to the concomitant increase in testosterone production, the relative modest effect on estradiol production, or a combination of both factors. These results suggest that anastrozole therapy is unlikely to have an adverse effect on bone metabolism when taken over extended periods and may prove to be a valuable method of normalizing testosterone production in older men.     

Testosterone replacement therapy and prostate/seminal vesicle volume in Klinefelter's syndrome

Volume of prostate and seminal vesicles was measured in patients with Klinefelter's syndrome by means of transrectal ultrasonography before and after testosterone replacement therapy. Continuous suppression of plasma gonadotropin levels was not observed, and plasma levels of testosterone did not maintain the normal range. However, volume of prostate (p less than 0.001) and seminal vesicles (p less than 0.05) increased significantly after testosterone replacement therapy. Volume determination of prostate and seminal vesicles by means of transrectal ultrasonography is an available parameter for evaluating the adequacy of testosterone replacement therapy in Klinefelter's syndrome.     

Skeletal demineralization in Turner's syndrome

The bone mineral status of 17 girls with Turner's syndrome was evaluated by single photon absorptiometry. Bone mineral content (BMC) was 25.4% below that predicted by normalization for age, sex, height, weight, and bone width. Only 25% of this demineralization could be attributed to delayed skeletal maturation. Bones of girls who received estrogen replacement therapy were less demineralized than those of the others. The bone mineral deficit became less pronounced with advancing age. It could not be determined if the apparent effect of estrogens was related to age or if the apparent improvement with age was really due to an effect of estrogen treatment. For 8 subjects followed longitudinally there was no significant change in the BMC deficit.     

Skeletal demineralization in Turner's syndrome

Summary The bone mineral status of 17 girls with Turner's syndrome was evaluated by single photon absorptiometry. Bone mineral content (BMC) was 25.4% below that predicted by normalization for age, sex, height, weight, and bone width. Only 25% of this demineralization could be attributed to delayed skeletal maturation. Bones of girls who received estrogen replacement therapy were less demineralized than those of the others. The bone mineral deficit became less pronounced with advancing age. It could not be determined if the apparent effect of estrogens was related to age or if the apparent improvement with age was really due to an effect of estrogen treatment. For 8 subjects followed longitudinally there was no significant change in the BMC deficit.     

Evidence that type I osteoporosis results from enhanced responsiveness of bone to estrogen deficiency

Type I osteoporosis occurs within 20 years after menopause and is associated with excessive cancellous bone loss and fractures of the vertebrae and distal radius. We have suggested that it may be caused by estrogen deficiency plus some additional factor predisposing to excessive bone loss. One such factor might be a greater degree of sex steroid deficiency, a possibility that could not be previously excluded because assays of sufficient sensitivity have only recently become available. Thus, we studied 36 women with vertebral fractures due to typical high turnover type I postmenopausal osteoporosis and 36 normal postmenopausal women using new ultrasensitive assays with detection limits of 1 pg/ml for estradiol, 5 pg/ml for estrone and 5 ng/dl for testosterone to test if type I osteoporosis results from enhanced responsiveness of bone to estrogen deficiency. Mean levels of serum sex steroids were identical in both groups, but bone turnover was increased by up to 55% in the women with type I osteoporosis. Moreover, compared with controls, the osteoporotic women had a 51% higher (P<0.01) serum osteoprotegerin level, which was likely a compensatory response to the increased bone turnover. In the osteoporotic women, 1-year treatment with transdermal estrogen in 14 women reduced total deoxypyridinoline, an index of bone resorption, by 58% as compared with placebo treatment in 17 women (P<0.001). Thus, as compared to controls, postmenopausal osteoporotic women had comparable sex steroid levels but higher bone turnover levels that were responsive to estrogen therapy. This is consistent with the hypothesis that the greater bone loss in type I osteoporosis is the result of impaired responsiveness of bone to low postmenopausal levels of sex steroids.     

Endogenous estrogen levels and the effects of ultra-low-dose transdermal estradiol therapy on bone turnover and BMD in postmenopausal women.

In a randomized controlled trial of a 0.014 mg/d transdermal estradiol patch, serum bone turnover markers decreased to a greater degree in postmenopausal women with lower versus higher endogenous estradiol levels. This suggests that the protective effects of ultra-low-dose estrogen therapy on the postmenopausal skeletal health may depend critically on women's endogenous estrogen levels before treatment. INTRODUCTION: Postmenopausal women with very low or undetectable estradiol levels have lower BMD, increased bone turnover, and increased risk of hip and vertebral fracture. We assessed whether the effects of ultra-low-dose 0.014 mg/d transdermal estradiol (Menostar; Berlex, Montvale, NJ, USA) on bone turnover and BMD are influenced by endogenous estradiol levels. MATERIALS AND METHODS: We analyzed data from postmenopausal women (mean age, 66 yr) randomized to an 0.014-mg/d transdermal estradiol patch or placebo in the ultra-low-dose transdermal estrogen (ULTRA) trial. The free estradiol index (FEI), calculated as the ratio of total estradiol (by mass spectometry) to sex hormone-binding globulin (SHBG; by immunoradiometric assay) x 100, was used to estimate bioavailable estradiol at baseline. Among the 382 women who adhered to >or=80% of study medication, we examined change in serum osteocalcin and bone-specific alkaline phosphatase levels at 12 mo and total hip and lumbar spine BMD at 24 mo in each quintile of FEI. RESULTS: Compared with women in the highest quintile of FEI, those in the lowest quintile of FEI had a 26% greater reduction in bone-specific alkaline phosphatase and 15% greater reduction in osteocalcin in response to ultra-low estradiol treatment (p for trend across quintiles < 0.05). There was a trend toward greater improvement in total hip BMD (p = 0.06) but not spine BMD (p = 0.90) in those with lower versus higher FEI levels. CONCLUSIONS: The beneficial effects of ultra-low-dose 0.014-mg/d transdermal estrogen therapy on skeletal health may depend critically on women's endogenous estrogen levels before treatment.     

Serum osteoprotegerin and sex steroid levels in patients with prostate cancer

The relationship between sex steroids and osteoprotegerin (OPG) in patients with prostate cancer is not well established. Our aim was to evaluate serum OPG levels in patients with prostate cancer and its relationship with sex steroids, bone mineral density, bone turnover markers, and fractures. We performed a cross-sectional study including 91 patients with prostate cancer. We determined: bone mineral density by dual-energy x-ray absorptiometry, bone turnover markers, serum levels of sex steroids and osteoprotegerin, and prevalent radiographic vertebral fractures. Serum OPG levels were higher in patients with vertebral fractures (8.02 ± 2.0 vs 4.91 ± 0.28 pmol/L; P < .05). OPG level and the duration of hormonal therapy were related (r = 0.299, P = .004), but this association did not persist after adjustment for age. In patients without androgen deprivation therapy, serum OPG levels were correlated with the levels of total testosterone (r = 0.508, P = .001) and bioavailable testosterone (r = 0.311, P = .037). In patients receiving androgen deprivation therapy, serum OPG levels were correlated with levels of total estradiol (r = 0.199, P = .18), bioavailable estradiol (r = 0.37, P = .009), and free estradiol (r = 0.349, P = .016). In conclusion, in patients with prostate cancer treated with androgen deprivation therapy, serum OPG levels were correlated with the levels of total estradiol, bioavailable estradiol, and free estradiol. Our hypothesis is that in patients with androgen deprivation therapy, the higher relative estrogen levels could stimulate OPG production in response to the higher resorption state. Future prospective studies are needed to clarify the role of OPG in androgen deprivation therapy-mediated bone loss.     

Bone mass, bone turnover, vitamin D, and estrogen receptor gene polymorphisms in male to female transsexuals: effects of estrogenic treatment on bone metabolism of the male.

The effect of chronic administration of estrogens on bone and mineral metabolism in men is not known. We have studied the effect of chronic administration of estrogens on bone mineral metabolism in a group of transsexual (TS) Canarian men, who were taking estrogens for a minimum of 3 years. This is a cross-sectional study of cases and controls and we studied biochemical markers of bone remodeling, bone mineral density (BMD), and selected biochemical and hormonal features. TS subjects had shorter stature than controls, and after adjusting for height and weight, we found that they had lower values for serum-free testosterone and higher values for BMD, both in the lumbar spine and in femoral neck. Biochemistry, bone remodeling markers, and calcitropic hormone values were similar in both groups. Finally, the distributions of vitamin D receptor (BsmI) and estrogen receptor (ER-Pvu and ER-Xba) polymorphisms were also similar in both groups. We conclude that the chronic administration of estrogens in men may produce an increase in serum estradiol, a decrease in free testosterone levels, and an increase in BMD-both in lumbar spine and in femoral neck. We found no association between the transsexual phenotype and the distribution of vitamin D receptor (BsmI) and estrogen receptor (ER-Pvu and ER-Xba).     

Changes in bone turnover following gonadotropin-releasing hormone (GnRH) agonist administration and estrogen treatment in cynomolgus monkeys: a short-term model for evaluation of antiresorptive therapy

In this study we determine the early time course of estrogen deficiency-induced bone loss in the cynomolgus monkey and examine the potential of this method for evaluating antiresorptive therapies. In two groups of animals, estrogen deficiency was induced by the administration of a gonadotropin-releasing hormone agonist (GnRHa) and bone turnover was measured using biochemical markers. Two weeks after receiving GnRHa, serum estradiol decreased to below the detection limit in most animals and remained there through 6 months or until estrogen replacement started (months 4-6). Relative to untreated animals, urinary deoxypyridinoline (dPyr), as well as C- and N-telopeptides of type I collagen, were significantly elevated 4 weeks after receiving GnRHa. Serum osteocalcin increased in GnRHa-treated animals as early as week 4 and the level was significantly higher than in untreated control animals from weeks 8-24. Estradiol treatment returned all measures of bone turnover to control levels within 2 weeks. The use of biochemical markers as surrogates of bone turnover and loss was validated by measurement of bone mineral density (BMD), which showed a significant reduction at 6 months in estrogen-deficient animals. However, lumbar BMD in animals that received GnRHa and estradiol was similar to that in animals that had not received GnRHa. In conclusion, a monthly depot injection of GnRHa resulted in increased bone turnover due to estrogen deficiency, as early as 4 weeks after treatment. Estrogen administration returned bone turnover to control levels in 2 weeks. This method represents a valid model for evaluating antiresorptive agents in the short term in a nonhuman primate. Furthermore, the data suggest that changes in biochemical markers in response to antiresorptive therapy in humans may be detectable at much earlier timepoints than commonly used.     

Testosterone Therapy in Klinefelter''s Syndrome (A Prolonged Observation)/Testosteron-Therapie des Klinefelter-Syndroms (Eine langfristige Beobachtung)

Clinical observations and pituitary gonadal hormone data was gathered in six patients with Klinefelter's Syndrome during a prolonged period of time. The secondary sex characteristics increased and the gynecomastia generally disappeared. Personality changes were also noted. In half of the patients, the abnormal level of luteinizing and follicular stimulating hormone remained elevated. An enlarged sella turcica was discovered in one patient. It is concluded that testosterone therapy is beneficial in all patients with Klinefelter's Syndrome.