Juvenile stress enhances anxiety and alters corticosteroid receptor expression in adulthood

BACKGROUND

Exposure to stress in early life is correlated with the development of anxiety disorders in adulthood. The underlying mechanisms are not fully understood, but an imbalance in corticosteroid receptor (CR) expression in the limbic system, particularly the hippocampus, has been implicated in the etiology of anxiety disorders. However, little is known about how prepubertal stress in the so called "juvenile" period might alter the expression of these receptors.

AIMS

Therefore, the aim of this study was to investigate how stress experienced in the juvenile phase of life altered hippocampal expression of CRs and anxiety behaviors in adulthood.

MATERIALS AND METHODS

We used a rodent model to assess the effects of juvenile stress on hippocampal CR expression, and performance in three behavioral tests of anxiety in adulthood.

RESULTS

Juvenile stress (JS) increased anxiety-like behavior on the elevated plus maze, increased mineralocorticoid receptor (MR) expression, and decreased the ratio of glucocorticoid receptor (GR) to MR expression in the hippocampus of adult animals. Females demonstrated lower levels of anxiety-type behavior and increased activity in three behavioral tests, and had greater expression of GR and GR:MR ratio than males, regardless of treatment.

DISCUSSION AND CONCLUSION

These results demonstrate that JS can alter the expression and balance of CRs, providing a potential mechanism for the corresponding increase in anxiety behavior observed in adulthood. Further evidence for the role of CR expression in anxiety is provided by sex differences in anxiety behavior and corresponding alterations in CR expression.

The effects of an obesogenic diet during pregnancy on fetal growth and placental gene expression are gestation dependent

Exposure to overnutrition in utero may increase offspring cardiometabolic disease risk. A mouse model of maternal exposure to an obesogenic diet (DIO) was used to determine effects on fetal and placental weight and gene expression in mid- and late gestation. DIO altered placental gene expression in mid-gestation without differences in fetal or placental weights. Weight gain was attenuated in DIO dams in late gestation and male pup weight was reduced, however there were no persistent changes in placental gene expression. Differences in maternal weight gain and/or specific dietary components may impact on fetal and placental growth and later disease risk.

Maternal obesity has little effect on the immediate offspring but impacts on the next generation

Maternal obesity during pregnancy has been linked to an increased risk of obesity and cardiometabolic disease in the offspring, a phenomenon attributed to developmental programming. Programming effects may be transmissible across generations through both maternal and paternal inheritance, although the mechanisms remain unclear. Using a mouse model, we explored the effects of moderate maternal diet-induced obesity (DIO) on weight gain and glucose-insulin homeostasis in first-generation (F1) and second-generation offspring. DIO was associated with insulin resistance, hyperglycemia and dyslipidemia before pregnancy. Birth weight was reduced in female offspring of DIO mothers (by 6%, P = .039), and DIO offspring were heavier than controls at weaning (males by 47%, females by 27%), however there were no differences in glucose tolerance, plasma lipids, or hepatic gene expression at 6 months. Despite the relative lack of effects in the F1, we found clear fetal growth restriction and persistent metabolic changes in otherwise unmanipulated second-generation offspring with effects on birth weight, insulin levels, and hepatic gene expression that were transmitted through both maternal and paternal lines. This suggests that the consequences of the current dietary obesity epidemic may also have an impact on the descendants of obese individuals, even when the phenotype of the F1 appears largely unaffected.

Obesogens and obesity--an alternative view?

It is accepted that diet is a major contributor to the obesity epidemic, but environmental 'obesogenic' chemicals have also been suggested recently as playing a role, based on in vitro, animal and epidemiological studies. Using two such 'obesogen' examples (bisphenol A, certain phthalate esters), we argue that their association with obesity and obesity-related disorders in humans could be circumstantial, and thus non-causal, because a Western style diet increases exposure to these compounds. This possibility needs to be addressed before further (confounded) epidemiological studies on 'obesogens' are undertaken.

What is the evidence in humans that DNA methylation changes link events in utero and later life disease?

Development in utero is now recognized as crucial to determining later life disease susceptibility. Whilst mechanisms are poorly understood, there has been considerable interest in the potential role of epigenetic processes in intra-uterine programming of disease. Epigenetic modifications include various mechanisms that influence chromatin structure and gene expression. Here, we review emerging data from human studies that altered DNA methylation links intra-uterine events with later life disease. Further research in this field is needed to determine whether altered DNA methylation in target tissues can be used as a biomarker for the early identification of and intervention in individuals most at risk of later life disease.

Sex-specific effects of prenatal stress on glucose homoeostasis and peripheral metabolism in rats

Glucocorticoid overexposure during pregnancy programmes offspring physiology and predisposes to later disease. However, any impact of ethologically relevant maternal stress is less clear, yet of physiological importance. Here, we investigated in rats the short- and long-term effects in adult offspring of repeated social stress (exposure to an aggressive lactating female) during late pregnancy on glucose regulation following stress, glucose-insulin homoeostasis and peripheral expression of genes important in regulating glucose and lipid metabolism and glucocorticoid action. Prenatal stress (PNS) was associated with reduced birth weight in female, but not male, offspring. The increase in blood glucose with restraint was exaggerated in adult PNS males compared with controls, but not in females. Oral glucose tolerance testing showed no effects on plasma glucose or insulin concentrations in either sex at 3 months; however, at 6 months, PNS females were hyperinsulinaemic following an oral glucose load. In PNS males, plasma triglyceride concentrations were increased, with reduced hepatic mRNA expression of 5α-reductase and peroxisome proliferator-activated receptor α (Pparα (Ppara)) and a strong trend towards reduced peroxisome proliferator-activated receptor gamma coactivator 1α (Pgc1α (Ppargc1a)) and Pparγ (Pparg) expression, whereas only Pgc1α mRNA was affected in PNS females. Conversely, in subcutaneous fat, PNS reduced mRNA expression of 11β-hydroxysteroid dehydrogenase type 1 (11βhsd1), phosphoenolpyruvate carboxykinase (Pepck (Pck1)), adipose triglyceride lipase (Atgl) and diglyceride acyltransferase 2 (Dgat2) in females, but only Pepck mRNA expression was reduced in PNS males. Thus, prenatal social stress differentially programmes glucose homoeostasis and peripheral metabolism in male and female offspring. These long-term alterations in physiology may increase susceptibility to metabolic disease.

An unbalanced maternal diet in pregnancy associates with offspring epigenetic changes in genes controlling glucocorticoid action and foetal growth

OBJECTIVE

In epidemiological studies, adverse early-life conditions associate with subsequent cardiometabolic disease. Hypothesized causes include maternal malnutrition, foetal glucocorticoid overexposure and reduced growth factors. Animal studies suggest a role for epigenetic processes in maintaining early-life effects into adulthood, but human relevance is unknown. We aimed to investigate relationships between an unbalanced maternal diet in pregnancy, neonatal and adult anthropometric variables with methylation at key genes controlling tissue glucocorticoid action and foetal growth.

DESIGN

We studied 34 individuals aged 40 from the Motherwell cohort study whose mothers ate an unbalanced diet in pregnancy, previously linked with elevated blood pressure and cortisol in adult offspring.

MEASUREMENTS

DNA methylation at 11β-hydroxysteroid dehydrogenase type 2 (HSD2), glucocorticoid receptor (GR) and insulin-like growth factor 2 (IGF2) was measured by pyrosequencing on buffy coat DNA.

RESULTS

Methylation at specific CpGs in the HSD2 promoter and at one of the IGF2 differentially methylated regions (H19 ICR) correlated with neonatal anthropometric variables. CpG methylation within HSD2, GR and H19 ICR was positively associated with increased adiposity and blood pressure in adulthood. Methylation at GR (exon 1F) was increased in offspring of mothers with the most unbalanced diets in pregnancy.

CONCLUSIONS

Alterations in DNA methylation at genes important in regulating circulating cortisol levels, tissue glucocorticoid action, blood pressure and foetal growth are present in adulthood in association with both early-life parameters and cardiometabolic risk factors. The data indicate a persisting epigenetic link between early-life maternal diet and/or foetal growth and cardiovascular disease risk in humans.

Glucocorticoids as mediators of developmental programming effects

Epidemiological evidence suggests that exposure to an adverse environment in early life is associated with an increased risk of cardio-metabolic and behavioral disorders in adulthood, a phenomenon termed 'early life programming'. One major hypothesis for early life programming is fetal glucocorticoid overexposure. In animal studies, prenatal glucocorticoid excess as a consequence of maternal stress or through exogenous administration to the mother or fetus is associated with programming effects on cardiovascular and metabolic systems and on the brain. These effects can be transmitted to subsequent generations. Studies in humans provide some evidence that prenatal glucocorticoid exposure may exert similar programming effects on glucose/insulin homeostasis, blood pressure and neurodevelopment. The mechanisms by which glucocorticoids mediate these effects are unclear but may include a role for epigenetic modifications. This review discusses the evidence for glucocorticoid programming in animal models and in humans.

Proposed role for COUP-TFII in regulating fetal Leydig cell steroidogenesis, perturbation of which leads to masculinization disorders in rodents

Reproductive disorders that are common/increasing in prevalence in human males may arise because of deficient androgen production/action during a fetal ‘masculinization programming window’. We identify a potentially important role for Chicken Ovalbumin Upstream Promoter-Transcription Factor II (COUP-TFII) in Leydig cell (LC) steroidogenesis that may partly explain this. In rats, fetal LC size and intratesticular testosterone (ITT) increased ∼3-fold between e15.5-e21.5 which associated with a progressive decrease in the percentage of LC expressing COUP-TFII. Exposure of fetuses to dibutyl phthalate (DBP), which induces masculinization disorders, dose-dependently prevented the age-related decrease in LC COUP-TFII expression and the normal increases in LC size and ITT. We show that nuclear COUP-TFII expression in fetal rat LC relates inversely to LC expression of steroidogenic factor-1 (SF-1)-dependent genes (StAR, Cyp11a1, Cyp17a1) with overlapping binding sites for SF-1 and COUP-TFII in their promoter regions, but does not affect an SF-1 dependent LC gene (3β-HSD) without overlapping sites. We also show that once COUP-TFII expression in LC has switched off, it is re-induced by DBP exposure, coincident with suppression of ITT. Furthermore, other treatments that reduce fetal ITT in rats (dexamethasone, diethylstilbestrol (DES)) also maintain/induce LC nuclear expression of COUP-TFII. In contrast to rats, in mice DBP neither causes persistence of fetal LC COUP-TFII nor reduces ITT, whereas DES-exposure of mice maintains COUP-TFII expression in fetal LC and decreases ITT, as in rats. These findings suggest that lifting of repression by COUP-TFII may be an important mechanism that promotes increased testosterone production by fetal LC to drive masculinization. As we also show an age-related decline in expression of COUP-TFII in human fetal LC, this mechanism may also be functional in humans, and its susceptibility to disruption by environmental chemicals, stress and pregnancy hormones could explain the origin of some human male reproductive disorders.

Effect of androgen treatment during foetal and/or neonatal life on ovarian function in prepubertal and adult rats

We investigated the effects of different windows of testosterone propionate (TP) treatment during foetal and neonatal life in female rats to determine whether and when excess androgen exposure would cause disruption of adult reproductive function. Animals were killed prepubertally at d25 and as adults at d90. Plasma samples were taken for hormone analysis and ovaries serial sectioned for morphometric analyses. In prepubertal animals, only foetal+postnatal and late postnatal TP resulted in increased body weights, and an increase in transitory, but reduced antral follicle numbers without affecting total follicle populations. Treatment with TP during both foetal+postnatal life resulted in the development of streak ovaries with activated follicles containing oocytes that only progressed to a small antral (smA) stage and inactive uteri. TP exposure during foetal or late postnatal life had no effect upon adult reproductive function or the total follicle population, although there was a reduction in the primordial follicle pool. In contrast, TP treatment during full postnatal life (d1-25) resulted in anovulation in adults (d90). These animals were heavier, had a greater ovarian stromal compartment, no differences in follicle thecal cell area, but reduced numbers of anti-Mullerian hormone-positive smA follicles when compared with controls. Significantly reduced uterine weights lead reduced follicle oestradiol production. These results support the concept that androgen programming of adult female reproductive function occurs only during specific time windows in foetal and neonatal life with implications for the development of polycystic ovary syndrome in women.

Transmission of programming effects across generations

Numerous epidemiological studies have shown that exposure to an adverse environment in early life is associated with a substantially increased risk of later disease; a phenomenon termed 'early life programming'. There is increasing evidence that these effects may not be limited to the first, directly exposed generation but may also be transmissible to subsequent generations through non-genomic mechanisms. There are a number of mechanisms which may underpin the intergenerational transmission of the programmed phenotype, including persistence of the abnormal environment across generations, programmed effects on maternal physiology and the transmission of epigenetic information through the germline. In this review we discuss the evidence for these mechanisms in human and animal studies and the potential importance of this field for child health.

Multigenerational programming in the glucocorticoid programmed rat is associated with generation-specific and parent of origin effects

Exposure to an adverse early life environment is associated with increased cardio-metabolic disease risk, a phenomenon termed "programming." The effects of this are not limited to the exposed first (F1) generation but can be transmissible to a second generation (F2) through male and female lines. Using a three generation animal model of programming by initial prenatal glucocorticoid overexposure we have identified effects on fetal and placental weight in both the F1 and F2 offspring. However, the expression of candidate imprinted genes in the fetus and placenta differed between the F1 and F2, with marked parent-of-origin effects in F2. Since DNA methylation at imprinted genes is maintained at fertilization, they are potential templates for the transmission of programming effects across generations. Although we detected alterations in DNA methylation at differentially methylated regions (DMRs) of the key prenatal growth factor Igf2 in F1 and F2 fetal liver, the changes in DNA methylation at these DMRs do not appear to underlie the transmission of effects on Igf2 expression through sperm. Thus, multigenerational programming effects on birth weight and disease risk is associated with different processes in F1 and F2. These findings have implications for the pathogenesis and future attempts to stratify therapies for the "developmental component" of cardiometabolic disease.

Maternal cigarette smoking and effects on androgen action in male offspring: unexpected effects on second-trimester anogenital distance

INTRODUCTION

Fertility, sperm counts, and testis weights are reduced in men whose mothers smoked in pregnancy. Animal studies suggest this could be due to impaired androgen action. Anogenital distance (AGD) provides a readout of fetal androgen exposure and is reduced by in utero exposure to harmful chemicals in rodents. This study assessed whether maternal cigarette smoking disturbs AGD in the second trimester human fetus.

MATERIALS AND METHODS

Morphological indices, including AGD, and circulating cotinine concentrations were measured in 83 electively terminated, normally progressing, second-trimester fetuses between 11 and 20 wk gestation.

RESULTS

A gender difference in AGD (1.4-fold longer in males) was already apparent at 11-13 wk, rising to 2.00-fold longer in males at 17-20 wk gestation. In males, AGD and AGD normalized against ponderal index (a measure of fetal leanness) were significantly increased by maternal smoking (1.19- and 1.31-fold, respectively). The difference between smoke-exposed and nonexposed male AGD was greatest at 11-13 wk (1.25-fold) but had declined to 1.01-fold by 17-20 wk gestation. AGD in females was not affected by maternal cigarette smoking.

CONCLUSIONS

Androgen programming of masculinization occurs before 11-13 wk gestation in the human because AGD is already significantly longer in male fetuses by that stage. AGD reaches the 2-fold difference reported for the neonate by 17-20 wk gestation. Significantly longer AGD in smoke-exposed males was surprising and may indicate increased androgen exposure in the early programming window. Convergence of AGD by late second trimester suggests, however, that by birth, male AGD may be shorter in smoke-exposed individuals.

Evaluation of pituitary function after traumatic brain injury in childhood

OBJECTIVES

Post-traumatic hypopituitarism is well described amongst adult traumatic brain injury (TBI) survivors. We aimed to determine the prevalence and clinical significance of pituitary dysfunction after head injury in childhood.

DESIGN

Retrospective exploratory study.

PATIENTS

33 survivors of accidental head injury (27 boys). Mean (range) age at study was 13·4 years (5·4-21·7 years) and median (range) interval since injury 4·3 years (1·4-7·8 years). Functional outcome at study: 15 good recovery, 16 moderate disability, two severe disability.

MEASUREMENTS

Early morning urine osmolality and basal hormone evaluation were followed by the gonadotrophin releasing hormone (GnRH) and insulin tolerance (n = 25) or glucagon tests (if previous seizures, n = 8). Subjects were not primed. Head injury details were extracted from patient records.

RESULTS

No subject had short stature (mean height SD score +0·50, range -1·57 to +3·00). Suboptimal GH responses (<5 μg/l) occurred in six peri-pubertal boys (one with slow growth on follow-up) and one postpubertal adolescent (peak GH 3·2 μg/l). Median peak cortisol responses to insulin tolerance or glucagon tests were 538 and 562 nm. Nine of twenty-five and two of eight subjects had suboptimal responses, respectively, two with high basal cortisol levels. None required routine glucocorticoid replacement. In three, steroid cover was recommended for moderate/severe illness or injury. One boy was prolactin deficient. Other basal endocrine results and GnRH-stimulated LH and FSH were appropriate for age, sex and pubertal stage. Abnormal endocrine findings were unrelated to the severity or other characteristics of TBI or functional outcome.

CONCLUSIONS

No clinically significant endocrinopathy was identified amongst survivors of accidental childhood TBI, although minor pituitary hormone abnormalities were observed.

Impact of maternal obesity on offspring obesity and cardiometabolic disease risk

The prevalence of obesity among pregnant women is increasing. In addition to the short-term complications of obesity during pregnancy in both mother and child, it is now recognised that maternal obesity has long-term adverse outcomes for the health of her offspring in later life. Evidence from both animal and human studies indicates that maternal obesity increases the risk for the offspring in developing obesity and altering body composition in child- and adulthood and, additionally, it also has an impact on the offspring's cardiometabolic health with dysregulation of metabolism including glucose/insulin homoeostasis, and development of hypertension and vascular dysfunction. Potential mechanisms include effects on the development and function of adipose tissue, pancreas, muscle, liver, the vasculature and the brain. Further studies are required to elucidate the mechanisms underpinning the programming of disease risk in the offspring as a consequence of maternal obesity. The ultimate aim is to identify potential targets, which may be amenable to prevention or early intervention in order to improve the health of this and future generations.

Prenatal dexamethasone programs expression of genes in liver and adipose tissue and increased hepatic lipid accumulation but not obesity on a high-fat diet

The association between low birth weight and cardiovascular disease is amplified by the development of obesity. We explored the effects of postnatal high-fat (HF) feeding in dexamethasone (Dex)-programmed rats, in which prenatal glucocorticoid overexposure is associated with reduced birth weight and adult glucose intolerance. Male Wistar rats exposed to Dex or vehicle (Veh) during the last week of gestation were weaned onto HF or control diets for 6 months. Dex-exposed animals were of lower birth weight and showed catch-up growth by 7 wk. There were no differences in obesity or hyperinsulinaemia between Dex-HF and Veh-HF animals. However, Dex-HF animals had increased hepatic triglyceride content compared with Veh-HF animals. mRNA transcript profiles in adipose tissue revealed depot-specific changes in the expression of genes involved in fatty acid esterification and triglyceride synthesis and storage with prenatal Dex exposure. Thus, antenatal glucocorticoid overexposure in rats does not confer increased sensitivity to HF diet-induced obesity, but increases susceptibility to fatty liver. This may be due to depot-specific-programmed alterations in fat metabolism in adipose tissue.

Intergenerational transmission of programmed effects: public health consequences

Epidemiological studies have shown that the environment experienced in early life can 'programme' susceptibility to later disease. Furthermore, there is increasing evidence that these effects can be transmissible to subsequent generations through non-genomic mechanisms, with profound implications for human populations. Several mechanisms can underpin the intergenerational transmission of the programmed phenotype, including persistence of the abnormal environment across generations, maternal effects and the transmission of epigenetic information through the germline. In this review, we discuss the evidence for these mechanisms in human and animal studies and the potential importance of this field for human health.

Androgen action in the masculinization programming window and development of male reproductive organs

We have shown previously that deficient androgen action within a masculinization programming window (MPW; e15.5-e18.5 in rats) is important in the origin of male reproductive disorders and in programming male reproductive organ size, but that androgen action postnatally may be important to achieve this size. To further investigate importance of the MPW, we used two rat models, in which foetal androgen production or action was impaired during the MPW by exposing in utero to either di(n-butyl) phthalate (DBP) or to flutamide. Reduced anogenital distance (AGD) was used as a monitor of androgen production/action during the MPW. Offspring were evaluated in early puberty (Pnd25) to establish if reproductive organ size was altered. The testes, penis, ventral prostate (VP) and seminal vesicles (SV) were weighed and penis length measured. Both DBP and flutamide exposure in the MPW significantly reduced penis, VP and SV size along with AGD at Pnd25; AGD and organ size were highly correlated. In DBP-, but not flutamide-, exposed animals, testis weight was also reduced and correlated with AGD. Intratesticular testosterone was also measured in control and DBP-exposed males during (e17.5) or after (e21.5) the MPW and related to AGD at e21.5. To evaluate the importance of postnatal androgen action in reproductive organ growth, the effect of combinations of prenatal and postnatal maternal treatments on AGD and penis size at Pnd25 was evaluated. In prenatally DBP-exposed animals, further postnatal exposure to either DBP or flutamide significantly reduced AGD and penis size in comparison with prenatal DBP exposure alone. In comparison, rats exposed postnatally to testosterone propionate after prenatal vehicle-exposure showed considerable increase in these parameters vs. controls. In conclusion, we show that the size of all male reproductive organs is programmed by androgen exposure in the MPW, but that growth towards this size is dependent on androgen action postnatally.

Glucocorticoids amplify dibutyl phthalate-induced disruption of testosterone production and male reproductive development

Common male reproductive abnormalities including cryptorchidism, hypospadias, and low sperm counts may comprise a testicular dysgenesis syndrome (TDS), resulting from fetal testis dysfunction during a critical developmental period involving reduced androgen production/action. The recent increase in TDS prevalence suggests environmental/lifestyle factors may be etiologically important. The developing fetus is exposed to multimodal challenges, and we hypothesized that exposure to a combination of factors rather than single agents may be important in the pathogenesis of TDS. We experimentally induced fetal testis dysfunction in rats via treatment of pregnant females daily from embryonic day (e) 13.5 to e21.5 with vehicle, 100 or 500 mg/kg . d dibutyl phthalate (DBP), 0.1 mg/kg . d dexamethasone (Dex), or a combination of DBP + Dex. In adulthood, penile length/normality, testis weight/descent, prostate weight, and plasma testosterone levels were measured plus anogenital distance (AGD) as a measure of androgen action within the masculinization programming window. Intratesticular testosterone and steroidogenic enzyme gene expression were measured in fetal testes at e17.5. High-dose DBP reduced fetal intratesticular testosterone and steroidogenic gene expression; induced mild hypospadias (31%) and cryptorchidism (53%); and reduced penile length, AGD, and testis and prostate weight in adulthood. Dex alone had no effect except to reduce birth weight but amplified the adverse effects of 500 mg/kg . d DBP and exacerbated the effects of 100 mg/kg . d DBP. All adverse effects were highly correlated to AGD, emphasizing the etiological importance of the masculinization programming window. These findings suggest that exposure to common environmental chemicals in combination with, for example, maternal stress, may increase the risk of common male reproductive abnormalities, with implications for human populations.

Primary care fellowship in diabetes: an innovative program in postgraduate diabetes education

BACKGROUND

To address the need of caring for the growing number of patients with diabetes, East Carolina University implemented a 1-year fellowship in diabetes. Most of the region has been designated as Health Professional Shortage Areas.

DESCRIPTION

The objective of the fellowship is to educate primary care physicians to serve as regional specialists in diabetes. The program is administered by physicians, educators, and representatives of the university's affiliated teaching hospital. The curriculum includes clinical, didactic, and experiential learning strategies in outpatient and inpatient settings. Adult and pediatric endocrinologists, obstetricians, and generalists mentor and evaluate the fellows.

EVALUATION

This innovative training program has improved the availability of high-quality diabetes care for underserved patients in the region. Mean glycemic control in fellows' patients improved and other clinical endpoints were also met.

CONCLUSIONS

A 1-year diabetes fellowship is a replicable solution to address the need for diabetes care specialists.

Relationship between androgen action in the "male programming window," fetal sertoli cell number, and adult testis size in the rat

Fetal androgen action is an important determinant of Sertoli cell (SC) number at birth. Androgens "program" reproductive tract development in rats between embryonic d (e) 15.5 and e17.5 ("male programming window"), and this is reflected for life by anogenital distance (AGD). We investigated if androgen regulation of SC number/proliferation was also programmed by androgens in this window. Pregnant rats were treated in various fetal time windows with vehicle (control) or 500 mg/kg.d di(n-butyl) phthalate (DBP), which suppresses fetal intratesticular testosterone (ITT). ITT and SC number/proliferation index were determined at e17.5 or e21.5; AGD was also determined at e21.5. In controls, SC number increased 11-fold and ITT by 10-fold from e17.5-e21.5. In animals exposed daily to DBP from e13.5, SC number was reduced by approximately 50% at e21.5, but increased 6-fold, as did ITT, from e17.5-e21.5; DBP had no effect on ITT at e15.5, reduced ITT by 50% at e17.5, and by more than 75% at e19.5-21.5. DBP exposure just in the male programming window did not alter SC number at e17.5 or 21.5 but reduced AGD. DBP treatment beyond e19.5 caused major reductions in SC number/proliferation index and ITT at e21.5. Only DBP treatments that included the male programming window led to reduced AGD at e21.5, but SC number was clearly not programmed in this window. Nevertheless, testis weight correlated highly (P<0.001) with AGD at e21.5, and postnatal d 25 and 90 in animals exposed in utero to vehicle or DBP (e13.5-e21.5). Thus, AGD may predict adult testis size but probably not through a direct relationship with SC number.

Mechanisms underlying the role of glucocorticoids in the early life programming of adult disease

Compelling epidemiological evidence suggests that exposure to an adverse intrauterine environment, manifested by low-birth weight, is associated with cardiometabolic and behavioural disorders in adulthood. These observations have led to the concept of ‘fetal programming’. The molecular mechanisms that underlie this relationship remain unclear, but are being extensively investigated using a number of experimental models. One major hypothesis for early life physiological programming implicates fetal overexposure to stress (glucocorticoid) hormones. Several animal studies have shown that prenatal glucocorticoid excess, either from endogenous overproduction with maternal stress or through exogenous administration to the mother or fetus, reduces birth weight and causes lifelong hypertension, hyperglycaemia and behavioural abnormality in the offspring. Intriguingly, these effects are transmitted across generations without further exposure to glucocorticoids, which suggests an epigenetic mechanism. These animal observations could have huge implications if extrapolated to humans, where glucocorticoids have extensive therapeutic use in obstetric and neonatal practice.

Effect of alendronate treatment on bone mineral density in male patients with osteoporosis

OBJECTIVE

To assess the efficacy of alendronate therapy on bone mineral density (BMD) at the lumbar spine and hip in men with osteoporosis.

METHODS

Medical records of male patients with osteoporosis, who had undergone follow-up in the Endocrinology Clinic at the National Naval Medical Center, were reviewed, and nine patients treated with alendronate for at least 1 year were identified. Patients were excluded from analysis if they had evidence of osteomalacia or if baseline and follow-up BMD results on the same dual-energy x-ray absorptiometry (DEXA) densitometer, at least 10 months apart, were not available. DEXA BMD results at the lumbar spine and hip, before and after at least 10 months of alendronate treatment, were analyzed for significant differences. Patients were also receiving calcium supplementation (1,000 to 1,500 mg/day), and all but one patient received vitamin D (400 to 800 U/day).

RESULTS

Lumbar spine BMD increased by 6.4 +/- 1.8% per year with alendronate treatment (P = 0.008). A mean absolute gain of 0.052 +/- 0.010 g/cm 2 (P = 0.005) in lumbar spine BMD was noted for the entire study group (N = 9), after a mean duration of treatment of 14 +/- 1 months. The mean lumbar spine BMD Z score improved by 0.40 +/- 0.09 (P = 0.002) with alendronate therapy. The femoral neck BMD also increased by 4.5 +/- 1.4% per year with alendronate treatment (P = 0.013). The mean absolute gain in femoral neck BMD was 0.028 +/- 0.009 g/cm 2 (P = 0.013) for the study group (N = 9) after 14 +/- 1 months of therapy. The mean femoral neck BMD Z score improved 0.30 +/- 0.08 (P = 0.005) with treatment. BMD gains at the greater trochanter of 3.2 +/- 1.5% per year (P = 0.067) and at Ward's triangle of 9.1 +/- 4.2% per year (P = 0.061) were not statistically significant. Two patients discontinued alendronate treatment after 1 year because of epigastric or retrosternal pain.

CONCLUSION

Oral alendronate treatment, given in combination with calcium supplementation and physiologic doses of vitamin D, resulted in significant improvements in lumbar spine and femoral neck BMD after a 14-month period in this small group of men with osteoporosis. Although controlled, prospective trials involving larger numbers of male patients with fracture incidence data are needed before definitive conclusions can be made, alendronate treatment seems to be effective in improving BMD in men with osteoporosis, similar to its efficacy in women.