Penile size in healthy Nigerian newborns: country-based reference values and international comparisons.

AIM: To establish normal reference values for penile size in Nigerian newborn boys and to compare those values with standards from other populations. METHODS: A total number of 261 healthy newborn boys delivered at gestational ages of 28 weeks or more were enrolled in the study. Penile lengths and widths were measured within 72 h of birth. RESULTS: The mean (±SD) penile length in the 261 Nigerian males studied was 3.4 ± 0.48 cm, while the mean mid-shaft diameter was 1.2 ± 0.14 cm. Compared with data from other populations, Nigerian newborn boys had similar penile sizes to those reported for US Caucasian boys (mean 3.4 cm), but significantly greater penile sizes than those reported for boys from China and Hong Kong (mean 3.0 and 3.1 cm, respectively; both p < 0.001). There was a slight, but significant, difference in size between Nigerian and Malaysian boys, with Malaysian boys having greater penile sizes (mean 3.5 cm; p < 0.05). CONCLUSION: A Nigerian newborn with a penile length of <2.39 cm can be considered to have a micropenis.

Boys with undescended testes: endocrine, volumetric and morphometric studies on testicular function before and after orchidopexy at nine months or three years of age.

CONTEXT: A randomized controlled study was conducted comparing the outcome of surgery for congenital cryptorchidism at 9 months or 3 yr of age. OBJECTIVE: The aim of the study was to investigate whether surgery at 9 months is more beneficial than at 3 yr and to identify early endocrine markers of importance for testicular development. PATIENTS AND METHODS: A total of 213 biopsies were taken at orchidopexy, and the number of germ and Sertoli cells per 100 seminiferous cord cross-sections and the surface area of seminiferous tubules and interstitial tissue were analyzed. Inhibin B, FSH, LH, and testosterone were determined. Testicular volume was assessed by ultrasonography and by a ruler. RESULTS: The number of germ and Sertoli cells and testicular volume at 9 months were significantly larger than at 3 yr. The intraabdominal testes showed the largest germ cell depletion at 3 yr. At both ages, testicular volume correlated to the number of germ and Sertoli cells. None of the hormones measured during the first 6 months of life (LH, FSH, testosterone, and inhibin B) could predict the number of germ or Sertoli cells at either 9 or 36 months of age, nor could hormone levels predict whether spontaneous descent would occur or not. CONCLUSION: Morphometric and volumetric data show that orchidopexy at 9 months is more beneficial for testicular development than an operation at 3 yr of age. Testicular volume was furthermore shown to reflect germ cell numbers in early childhood, whereas endocrine parameters could not predict cellular structure of the testis or its spontaneous descent.

Locally produced estrogen promotes fetal rat metatarsal bone growth; an effect mediated through increased chondrocyte proliferation and decreased apoptosis.

The importance of estrogens for the regulation of longitudinal bone growth is unequivocal. However, any local effect of estrogens in growth plate cartilage has been debated. Recently, several enzymes essential for estrogen synthesis were shown to be expressed in rat growth plate chondrocytes. Local production of 17beta-estradiol (E2) has also been demonstrated in rat costal chondrocytes. We aimed to determine the functional role of locally produced estrogen in growth plate cartilage. The human chondrocyte-like cell line HCS-2/8 was used to study estrogen effects on cell proliferation (3H-labeled thymidine uptake) and apoptosis (cell death detection ELISA kit). Chondrocyte production of E2 was measured by RIA and organ cultures of fetal rat metatarsal bones were used to study the effects of estrogen on longitudinal growth rate. We found that significant amounts of E2 were produced by HCS-2/8 chondrocytes (64.1 +/- 5.3 fmol/3 days/10(6) cells). The aromatase inhibitor letrozole (1 microM) and the pure estrogen receptor antagonist ICI 182,780 (10 microM) inhibited proliferation of HCS-2/8 chondrocytes by 20% (P < 0.01) and almost 50% (P < 0.001), respectively. Treatment with ICI 182,780 (10 microM) increased apoptosis by 228% (P < 0.05). Co-treatment with either caspase-3 or pan-caspase inhibitors completely blocked ICI 182,780-induced apoptosis (P < 0.001 vs ICI 182,780 only). Moreover, both ICI 182,780 (10 microM) and letrozole (1 microM) decreased longitudinal growth of fetal rat metatarsal bones after 7 days of culture (P < 0.01). In conclusion, our data clearly show that chondrocytes endogenously produce E2 and that locally produced estrogen stimulates chondrocyte proliferation and protects from spontaneous apoptosis. In addition, longitudinal growth is promoted by estrogens locally produced within the epiphyseal growth plate.

Growth retardation induced by dexamethasone is associated with increased apoptosis of the growth plate chondrocytes.

Glucocorticoids cause significant growth retardation in mammals and humans and decreased proliferation of chondrocytes has been considered as the main local mechanism. Death by apoptosis is an important regulator of homeostasis in multicellular organisms. Here we chose to study the role of apoptosis in growth retardation caused by glucocorticoid treatment. We treated 7-week-old male rats with dexamethasone (5 mg/kg/day) for 7 days. Apoptosis was studied in tibiae growth plates by the TUNEL method. Immunoreactivity for parathyroid hormone-related peptide (PTHrP), caspase-3, and the anti-apoptotic proteins Bcl-2 and Bcl-x was also studied. Apoptosis was mainly localized in terminal hypertropic chondrocytes (THCs) in both control and dexamethasone-treated animals. Dexamethasone caused an increase in apoptosis which was fourfold in THCs (2.45+/-0.12 vs 0.62+/-0.09 apoptotic cells/mm growth plate, P<0.001), and 18-fold in proliferative chondrocytes (0.18+/-0.04 vs 0.01+/-0.007 apoptotic cells/mm growth plate, P<0.001). Increased apoptosis after dexamethasone treatment was accompanied by increased immunoreactivity for caspase-3 and decreased immunoreactivity for the anti-apoptotic proteins Bcl-2 and Bcl-x, which further supports our apoptosis results. Dexamethasone also decreased the immunoreactivity for PTHrP, suggesting a role in the mechanism by which glucocorticoids induce apoptosis in the growth plate. We conclude that apoptosis is one mechanism involved in growth retardation induced by glucocorticoids. Premature loss of resting/proliferative chondrocytes by apoptosis could contribute to incomplete catch-up seen after prolonged glucocorticoid treatment.

Effect of local heating of rat testes after suppression of spermatogenesis by pretreatment with a GnRH agonist and an anti-androgen.

The effects of local heating of rat testes, in which spermatogenesis had been suppressed with injections of a GnRH agonist and an anti-androgen, were examined. Although the detrimental effects of heating were not as marked as those found in the testes of non-injected rats, the testes in which spermatogenesis was suppressed also showed a significant reduction in mass, the number of spermatozoa, tubular diameter and the percentage of normal tubular cross-sections at day 35 after heating. The results indicate that heating has an effect on cells in the testis other than those shown to be most susceptible to heat, namely pachytene spermatocytes and early spermatids, which were absent or markedly reduced in number when spermatogenesis was suppressed. The long-term effects of heating on the above parameters, as reported in a previous study, were also confirmed. However, in testes in which spermatogenesis was suppressed at the time of heating, there appeared to be no or a reduced long-term impairment of spermatogenesis, as determined by testis mass, the percentage of qualitatively normal tubules and epididymal sperm counts.

Estrogen receptor-alpha and -beta are expressed throughout postnatal development in the rat and rabbit growth plate.

Estrogen regulates skeletal growth and promotes epiphyseal fusion. To explore the mechanisms underlying these effects we investigated the expression of estrogen receptor-alpha (ERalpha) and -beta (ERbeta) in rat and rabbit growth plates during postnatal development, using immunohistochemistry. Immunoreactivity for ERalpha and ERbeta was observed in resting zone and proliferative zone chondrocytes at all ages studied for both rat (7, 14, 28 and 70 days of age) and rabbit (1, 7, 28 and 120 days of age). In the rat distal humerus and the rabbit proximal tibia, expression of both receptors in the hypertrophic zone was minimal at early ages, increasing only at the last time point prior to epiphyseal fusion. Expression was rarely seen in the hypertrophic zone of the rat proximal tibia, a growth plate that does not fuse until late in life. Therefore, we conclude that ERalpha and ERbeta are both expressed in the mammalian growth plate. The temporal and anatomical pattern suggests that ER expression in the hypertrophic zone in particular may play a role in epiphyseal fusion.

Endocrine dysfunction in Prader-Willi syndrome: a review with special reference to GH.

Prader-Willi syndrome is a genetic disorder occurring in 1 in 10,000-16,000 live-born infants. In the general population, approximately 60 people in every 1,000,000 are affected. The condition is characterized by short stature, low lean body mass, muscular hypotonia, mental retardation, behavioral abnormalities, dysmorphic features, and excessive appetite with progressive obesity. Furthermore, morbidity and mortality are high, probably as a result of gross obesity. Most patients have reduced GH secretory capacity and hypogonadotropic hypogonadism, suggesting hypothalamic-pituitary dysfunction. Replacement of GH and/or sex hormones may therefore be beneficial in Prader-Willi syndrome, and several clinical trials have now evaluated GH replacement therapy in affected children. Results of GH treatment have been encouraging: improved growth, increased lean body mass, and reduced fat mass. There was also some evidence of improvements in respiratory function and physical activity. The long-term benefits of GH treatment are, however, still to be established. Similarly, the role of sex hormone replacement therapy needs to be clarified as few data exist on its efficacy and potential benefits. In summary, Prader-Willi syndrome is a disabling condition associated with GH deficiency and hypogonadism. More active treatment of these endocrine disorders is likely to benefit affected individuals.

Reduction of long-term effects of local heating of the testis by treatment of rats with a GnRH agonist and an anti-androgen.

Heating the testes of anaesthetized adult rats to 43 degrees C for 30 min in a waterbath was followed by a large decrease in testis and epididymis mass and number of spermatozoa 35 days later. These parameters had recovered to some extent, but not completely, by days 70 and 97 after heating, but had decreased again in rats examined on day 182. There were no consistent effects of heating on androgen status, as determined by the concentrations of testosterone in blood and testis fluids, or by seminal vesicle mass, and interstitial fluid volume was increased in the heated testes. Treatment of rats with an implant of a GnRH agonist and daily injections of an anti-androgen for 14 days (sufficient in itself to cause large temporary decreases in tissue mass, number of spermatozoa and androgen status) did not reduce the initial decrease in testis mass or number of spermatozoa seen after heating, but reduced the later decreases in mass and number of spermatozoa significantly. These findings indicate that, as well as causing damage to spermatocytes and spermatids, as previously reported, heating also reduces the ability of spermatogonia to repopulate the seminiferous tubules at longer intervals after heating. Furthermore, it appears that this effect on the spermatogonia can be reduced by treating the animals with a GnRH agonist and anti-androgen, a treatment similar to that shown by other authors to improve recovery of the testis from irradiation or drug treatment.

Prenatal dexamethasone treatment of fetuses at risk for congenital adrenal hyperplasia: benefits and concerns.

Virilization due to congenital adrenal hyperplasia (CAH) can effectively be prevented or diminished by prenatal dexamethasone given to the mother. This treatment, which should only be considered in families with a previous child with a virilizing form of the disease, has to start already at 6-7 weeks of gestation. Thus, the treatment has to be given 'blindly' to all mothers at risk until the diagnosis of an affected female can be ascertained by analysis of DNA from a chorionic villous biopsy, which cannot be performed until the 10th week. Since CAH is inherited as an autosomal recessive disease and only affected girls benefit from the treatment, seven out of eight fetuses are treated unnecessarily. This makes it especially important to monitor possible side effects. Adverse effects on brain and kidneys have been shown in animals exposed to large doses of dexamethasone during the second trimester. Too few follow-up human studies are reported to date to allow definite conclusions on possible side effects in man. Therefore, treatment should be done within controlled clinical studies.

Eating behavior in Prader-Willi syndrome, normal weight, and obese control groups.

OBJECTIVE: Hyperphagia in Prader-Willi syndrome (PWS) is hypothesized to be due to hypothalamic dysfunction; thus the study of individuals with PWS might illustrate how hypothalamic dysfunction affects eating behavior. The aim of this study was to document the microstructure of the eating behavior in patients with PWS and to compare it with that of members of obese and normal weight control groups of the same age. STUDY DESIGN: Nine subjects with PWS (age, 10 +/- 4 years), 20 normal weight subjects (age, 12 +/- 3 years), and 20 obese subjects (age, 12 +/- 4 years) were served an excess lunch meal (hash) on a hidden scale built into a table and connected to a computer. The plate of food is placed on top of the scale, and when the food is eaten, the change in food weight is registered continuously. An eating curve is displayed online. After the meal, the eating data are fitted to a polynomial, and the computer calculates the amount of food eaten, time of consumption, eating rate (initial and total), and rate of deceleration. RESULTS: Subjects with PWS were found to have a longer duration of eating (P =.04) and a slower initial eating rate (P =. 01) compared with members of both obese and normal weight groups. In subjects with PWS, 56% of the eating curves were non-decelerating (linear or accelerating) compared with 10% of the normal weight group and 30% of the obese group (P =.02). CONCLUSION: The microstructure of the eating behavior in subjects with PWS differs from that of members of obese and normal weight control groups. Thus the eating behavior found in subjects with PWS might be due to decreased satiation rather than increased hunger.

How can molecular biology contribute to the management of congenital adrenal hyperplasia?

The most common form of congenital adrenal hyperplasia is due to a deficiency of 21-hydroxylase (21OHD) activity and is caused by a mutation in the CYP21 gene. By genotyping patients, new and important information can be gained, including presence or absence of 21OHD in borderline cases, determining the severity of disease and identifying heterozygote carriers. Current management of patients with 21OHD involves administering sufficient glucocorticoids to suppress excess adrenal androgen secretion, but not so much that bone growth and mineralization are impaired. New management strategies have been proposed and include administering only substitution doses of corticosteroids and counteracting side-effects by administering an anti-androgen and aromatase inhibitor. Adrenalectomy has also been proposed. Further investigation into these approaches is necessary.

Characterisation of novel missense mutations in the GH receptor gene causing severe growth retardation.

Two Swedish brothers, 2.5 and 4 years of age, were found to fulfil all the clinical and laboratory characteristics of Laron's syndrome. They were shown to have unique missense mutations in the GH receptor gene. Both of their parents were of normal height, but they both separately carried one of the identified gene alterations. A molecular model of the first receptor alteration suggests that a collapse in three-dimensional receptor structure most likely contributed to the GH insensitivity in these patients.

Androgen and estrogen stimulation of ornithine decarboxylase activity in mouse kidney.

In the present work, the activity of mouse renal ornithine decarboxylase (ODC) from CBA female mice was used as a biological marker to detect (anti)androgenic activity of different groups of endocrine disruptors and steroids. Daily injections of testosterone or dihydrotestosterone (DHT) into 60 day old female mice for 4 days increased renal ODC activity in a dose-dependent manner that reached up to 100-fold (testosterone) or 250-fold (DHT) above the baseline when the highest dose, 200 microg/mouse, was used. Administration of flutamide concurrently with testosterone (75 microg/mouse) caused a potent decrease of ODC induction in a dose-dependent manner, suppressing the enzyme activity at the doses of 0.1 and 0.5 mg/mouse by about 88 and 95%, respectively. In contrast, estradiol at the doses of 0.5 and 1 mg/mouse induced a significant stimulation of renal ODC activity in a dose-dependent manner when it was given alone or in combination with testosterone. Using a sensitive increase in ODC activity in response to androgens as an end point, we did not detect an antiandrogenic effect of several antiandrogens, such as cyproterone acetate, spironolactone, p,p'DDE and vinclozolin. Also, none of these antiandrogens were able to change the basal level of renal ODC activity, with the exception of cyproterone acetate that at a dose of 0.1 mg/mouse stimulated ODC activity. The data obtained suggest that mouse renal ODC from CBA females is not strictly androgen-specific and cannot be used for estimation of antiandrogenic effects of compounds having an affinity to different types of receptors.

Growth hormone treatment increases CO(2) response, ventilation and central inspiratory drive in children with Prader-Willi syndrome.

UNLABELLED: We studied whether the beneficial effects of growth hormone (GH) treatment on growth and body composition in PWS are accompanied by an improvement in respiratory function. We measured resting ventilation, airway occlusion pressure (P(0.1)) and ventilatory response to CO(2) in nine children, aged 7-14 years, before and 6-9 months after the start of GH treatment. During GH treatment, resting ventilation increased by 26%, P(0.1) by 72% and the response to CO(2) by 65% (P < 0.002, <0.04 and <0.02, respectively). This observed increase in ventilatory output was not correlated to changes in body mass index. CONCLUSION: Treatment of children with Prader-Willi syndrome (PWS) seems to have a stimulatory effect on central respiratory structures. The observed increase in ventilation and inspiratory drive may contribute to the improved activity level reported by parents of PWS children during growth hormone therapy.

Disproportional body growth in female estrogen receptor-alpha-inactivated mice.

Estrogens play an important role in the regulation of longitudinal bone growth in man, as demonstrated by recent descriptions of individuals with estrogen insensitivity or aromatase deficiency. Two estrogen receptors, ERalpha and ERbeta, have been cloned. The aim of the present study was to investigate the function of ERalpha in the regulation of body growth and skeletal growth. Adult female mice with inactivated ERalpha (ERalpha-/-) demonstrated an increased body weight compared with wild-type mice (114% of control). However, the length of the appendicular skeleton was decreased in adult ERalpha-/- mice (femur 93% of control). In contrast, the axial skeleton was normal (crown-rump length 98% of control). The decreased growth of the appendicular skeleton was associated with decreased serum levels of IGF-I (77% of control), indicating that the GH/IGF-I axis may be involved in the decreased longitudinal bone growth seen in female ERalpha-/- mice.

Growth hormone treatment of children with Prader-Willi syndrome: effects on glucose and insulin homeostasis. Swedish National Growth Hormone Advisory Group.

Insulin and glucose homeostasis have been studied during growth hormone (GH) treatment in 19 prepubertal children with Prader-Willi syndrome (PWS) and compared with 11 healthy prepubertal obese children. Before treatment, insulin levels in children with PWS were lower (p < 0.01) than in healthy obese children. During GH treatment, fasting insulin levels increased in children with PWS (p < 0.001). Glucose levels were similar for PWS and obese children before treatment. Children with PWS showed a slow glucose disappearance rate (k = 1.7%) which deteriorated (k = 1.3%, p < 0.001) during GH treatment. HbA1c and fasting glucose levels remained normal. Thus, GH treatment of children with PWS resulted in increased insulin blood levels, unchanged fasting glucose and HbA1c but decreased glucose elimination rate after an intravenous glucose test. However, the observed dose-dependent increase in insulin levels during GH treatment, that reached supranormal concentrations in 6/19 patients, and the occurrence of NIDDM in 1 patient during follow-up suggest that close surveillance and low doses of GH should be applied, especially if the PWS patient is very obese.

Beneficial effects of dietary supplementation in a disorder with defective synthesis of cholesterol. A case report of a girl with Smith-Lemli-Opitz syndrome, polyneuropathy and precocious puberty.

In 1993 the Smith-Lemli-Opitz (SLO) syndrome, known as a malformation syndrome characterized by certain stigma, turned out to be a metabolic disease with a defect in the last step of cholesterol biosynthesis. This led to the possibility of identifying affected individuals by biochemical methods and of increasing understanding of pathogenic mechanisms. Hopes of influencing the effects of the metabolic defect by dietary supplementation were raised and reports with some benefits of treatment have been published. This is a report of a 12-y-old girl with the SLO syndrome in an apparently progressive form. In addition to typical signs and well-known symptoms she has a verified polyneuropathy and precocious puberty. She has been treated with cholesterol and bile acids for 3 y, during which time the progressive course has been arrested. A notable effect has been the improvement of her polyneuropathy, verified by measurement of nerve conduction velocities. Possible mechanisms involved in the pathogenesis of her precocious puberty are discussed.

Failure of cortisone acetate treatment in congenital adrenal hyperplasia because of defective 11beta-hydroxysteroid dehydrogenase reductase activity.

Congenital adrenal hyperplasia in children is often treated with cortisone acetate and fludrocortisone. It is known that certain patients with congenital adrenal hyperplasia require very high substitution doses of cortisone acetate, and a few patients do not respond to this treatment at all. A patient with 21-hydroxylase deficiency, for whom elevated pregnanetriol (P3) levels in urine were not suppressed during treatment with cortisone acetate (65 mg/m2 x day), was examined. The activation of cortisone to cortisol was assessed by measuring urinary metabolites of cortisone and cortisol. The patient's inability to respond to treatment with cortisone acetate was found to be caused by a low conversion of cortisone to cortisol, assumed to be secondary to low 11beta-hydroxysteroid dehydrogenase activity (11-oxoreductase deficiency). All exons and exon/intron junctions of the 11beta-hydroxysteroid dehydrogenase type1 gene (HSD11L) were sequenced without finding any mutations, but a genetic lesion in the promoter or other regulatory regions cannot be ruled out. The deficient 11-oxoreductase activity seems to have been congenital, in this case, but can possibly be attributable to a down-regulation of the enzyme activity. The results support the use of hydrocortisone, rather than cortisone acetate, for substitution therapy in adrenal insufficiency.

Demonstration of estrogen receptor-beta immunoreactivity in human growth plate cartilage.

Estrogens affect longitudinal bone growth through their action on endochondral bone formation. Two estrogen receptors are known, the classical estrogen receptor-alpha (ER alpha), newly demonstrated in human growth plate cartilage, and a recently cloned estrogen receptor-beta (ER beta). The present study aimed to localize a possible expression of ER beta protein in human growth plates. Tissue samples were obtained from tibial and femoral growth plates in four female pubertal patients undergoing epiphyseal surgery. Immunohistochemistry, using two different ER beta-specific antibodies, demonstrated positive staining for ER beta in hypertrophic epiphyseal chondrocytes from all patients. No staining was noted in resting or proliferative chondrocytes. These data suggest that in addition to ER alpha, human epiphyseal chondrocytes also express ER beta. The physiological role of ER beta in the regulation of longitudinal bone growth in humans remains to be elucidated.