Circadian variation of serum leptin in healthy and diabetic men

Impact of metabolic syndrome on bone mineral density in men over 50 and postmenopausal women according to U.S. survey results

Metabolic Syndrome (MetS) and bone mineral density (BMD) have shown a controversial link in some studies. This research aims to study their association in males over 50 and postmenopausal females using National Health and Nutrition Examination Survey (NHANES) data. Postmenopausal females and males over 50 were included in the study. MetS was defined by the National Cholesterol Education Program Adult Treatment Panel III guidelines. BMD values were measured at the thoracic spine, lumbar spine, and pelvis as the primary outcome. Weighted multivariate general linear models have been employed to explore the status of BMD in patients with MetS. Additionally, interaction tests and subgroup analyses were conducted. Utilizing the NHANES database from 2003 to 2006 and 2011-2018, we included 1924 participants, with 1029 males and 895 females. In postmenopausal women, after adjusting for covariates, we found a positive correlation between MetS and pelvic (β: 0.030 [95%CI 0.003, 0.06]) and thoracic (β: 0.030 [95%CI 0.01, 0.06]) BMD, though not for lumbar spine BMD (β: 0.020 [95%CI - 0.01, 0.05]). In males over 50 years old, MetS was positively correlated with BMD in both Model 1 (without adjusting for covariates) and Model 2 (considering age and ethnicity). Specifically, Model 2 revealed a positive correlation between MetS and BMD at the pelvis (β: 0.046 [95%CI 0.02, 0.07]), thoracic spine (β: 0.047 [95%CI 0.02, 0.07]), and lumbar spine (β: 0.040 [95%CI 0.02, 0.06]). Subgroup analysis demonstrated that the relationship between MetS and BMD remained consistent in all strata, underscoring the stability of the findings. In postmenopausal women, after adjusting for all covariates, a significant positive correlation was observed between MetS and BMD in the pelvis and thoracic spine, whereas this correlation was not significant for lumbar spine BMD. Conversely, in males, positive correlations between MetS and BMD at the lumbar spine, thoracic spine, and pelvis were identified in Model 2, which adjusted for age and ethnicity; however, these correlations disappeared after fully adjusting for all covariates. These findings highlight the potential moderating role of gender in the impact of MetS on BMD.

Association of type 2 Diabetes Mellitus and bone mineral density: a two-sample Mendelian randomization study

BACKGROUND

Observational studies have suggested that type 2 Diabetes Mellitus (DM2) is a potentially modifiable risk factor for lower BMD, but the causal relationship is unclear. This study aimed to examine whether the association of DM2 with lower BMD levels was causal by using Mendelian randomization (MR) analyses.

METHODS

We collected genome-wide association study data for DM2 and BMD of total body and different skeletal sites from the IEU database. Subsequently, we performed a two-sample Mendelian randomization analysis using the Two Sample MR package.

RESULTS

We identified a positive association between DM2 risk (61,714 DM2 cases and 596,424 controls) and total BMD, and other skeletal sites BMD, such as femoral neck BMD, ultra-distal forearm BMD and heel BMD. However, non-significant trends were observed for the effects of DM2 on lumbar-spine BMD.

CONCLUSION

In two-sample MR analyses, there was positive causal relationship between DM2 and BMD in both overall samples. In summary, while observational analyses consistently indicate a strong association between DM2 and low BMD, our MR analysis introduces a nuanced perspective. Contrary to the robust association observed in observational studies, our MR analysis suggests a significant link between DM2 and elevated BMD.

Harnessing the Power of Leptin: The Biochemical Link Connecting Obesity, Diabetes, and Cognitive Decline

In this review, the current understanding of leptin’s role in energy balance, glycemic regulation, and cognitive function is examined, and its involvement in maintaining the homeostatic “harmony” of these physiologies is explored. The effects of exercise on circulating leptin levels are summarized, and the results of clinical application of leptin to metabolic disease and neurologic dysfunction are reviewed. Finally, pre-clinical evidence is presented which suggests that synthetic peptide leptin mimetics may be useful in resolving not only the leptin resistance associated with common obesity and other elements of metabolic syndrome, but also the peripheral insulin resistance characterizing type 2 diabetes mellitus, and the central insulin resistance associated with certain neurologic deficits in humans.

Probiotics Treatment of Leg Diseases in Broiler Chickens: a Review

Normal development and growth of bones are critical for poultry. With the rapid growth experienced by broiler chickens, higher incidences of leg weakness and lameness are common problems in adolescent meat-type poultry that present huge economic and welfare issues. Leg disorders such as angular bone deformities and tibial dyschondroplasia have become common in broilers and are associated with poor growth, high mortality rates, increased carcass condemnation, and downgrading at slaughter. Probiotics have shown promise for a variety of health purposes, including preventing diarrhea, elevating carcass quality, and promoting growth of the poultry. In addition, recent studies have indicated that probiotics can maintain the homeostasis of the gut microbiota and improve the health of the gastrointestinal tract, which confers a potentially beneficial effect on bone health. This review mainly describes the occurrence of broiler leg disease and the role of probiotics in bone health through regulating the gut microbiota and improving intestinal function, thus providing a relevant theoretical basis for probiotics to hinder the development of skeletal disorders in broiler chickens.

Moderate Weight Loss Modifies Leptin and Ghrelin Synthesis Rhythms but Not the Subjective Sensations of Appetite in Obesity Patients

Obesity is characterized by a resistance to appetite-regulating hormones, leading to a misalignment between the physiological signals and the perceived hunger/satiety signal. A disruption of the synthesis rhythm may explain this situation. The aim of this study was to evaluate the effect of dietary-induced weight loss on the daily rhythms of leptin and ghrelin and its influence on the daily variability of the appetite sensations of patients with obesity. Twenty subjects with obesity underwent a hypocaloric dietary intervention for 12 weeks. Plasma leptin and ghrelin were analyzed at baseline and at the end of the intervention and in 13 normal-weight controls. Appetite ratings were analyzed. Weight loss decreased leptin synthesis (pauc < 0.001) but not the rhythm characteristics, except the mean variability value (pmesor = 0.020). By contrast, the mean ghrelin level increased after weight loss. The rhythm characteristics were also modified until a rhythm similar to the normal-weight subjects was reached. The amount of variability of leptin and ghrelin was correlated with the effectiveness of the dietary intervention (p < 0.020 and p < 0.001, respectively). Losing weight partially restores the daily rhythms of leptin and modifies the ghrelin rhythms, but appetite sensations are barely modified, thus confirming that these hormones cannot exercise their physiological function properly.

The yo-yo effect of Ramadan fasting on overweight/obese individuals in Indonesian: A prospective study

BACKGROUND: Ramadan fasting has been associated with a significant body weight, fat mass and waist-hip circumference reduction. However, this is mostly followed by weight regain in 2 weeks after the fasting is stopped. Currently there is no explanation on how this rebound phenomena occurred. OBJECTIVE: The aim of this study was to examine the role of lifestyle and hormonal background on weight regain after Ramadan fasting in overweight individuals. METHODS: This was an observational study with prospective cohort design. Subjects were overweight/obese men and women adults with age between 21 and 56 years old. Body weight, percent fat, fat free mass and hip-waist circumference were measured before (week 0), 28 days after Ramadan fasting (week 4) and 2 weeks after the end of Ramadan (week 6). In addition, data on lifestyle factors such as dietary intake and physical activity were collected in those time points. Leptin was measured before and at the end of Ramadan fasting period. RESULTS: Body weight was significantly reduced at the end of Ramadan (week 4, p < 0,0001) and increased after Ramadan (week 6, p < 0,0001). Leptin was significantly reduced after Ramadan (p = 0,018) and we found that leptin level at the end of Ramadan was associated with percent body weight reduction (p = 0,011). CONCLUSION: We conducted a study to understand Ramadan fasting yo-yo effect in overweight and obese individuals and this study showed that dietary factor prior to the fasting has a significant impact on overweight/obese individual.

Diabetes, diabetic complications, and fracture risk

Diabetes and osteoporosis are both common diseases with increasing prevalences in the aging population. There is increasing evidence corroborating an association between diabetes mellitus and bone. This review will discuss the disease complications of diabetes on the skeleton, highlighting findings from epidemiological, molecular, and imaging studies in animal models and humans. Compared to control subjects, decreased bone mineral density (BMD) has been observed in type 1 diabetes mellitus, while on average, higher BMD has been found in type 2 diabetes; nonetheless, patients with both types of diabetes are seemingly at increased risk of fractures. Conventional diagnostics such as DXA measurements and the current fracture risk assessment tool (FRAX) risk prediction algorithm for estimating risk of osteoporotic fractures are not sufficient in the case of diabetes. A deterioration in bone microarchitecture and an inefficient distribution of bone mass with insufficiency of repair and adaptation mechanisms appear to be factors of relevance. A highly complex and heterogeneous molecular pathophysiology underlies diabetes-related bone disease, involving hormonal, immune, and perhaps genetic pathways. The detrimental effects of chronically elevated glucose levels on bone should be added to the more well-known complications of diabetes.

Assessment of Maxillary and Mandibular Bone Density in Controlled Type II Diabetes: A Computed Tomography Study

This study was undertaken to compare the bone density in nondiabetic and controlled type II diabetes patients using spiral computed tomography. A group of 40 edentulous men, comprising of 20 nondiabetics and 20 controlled type II diabetics between the ages of 50-65 years, were enrolled in the study. Glycemic control of the diabetic patients was assessed by glycosylated hemoglobin level. The controlled diabetic group had an HbA1c level between 6.1-8%. A radiographic stent was prepared by using chemically cured resin. Bone densities at trabecular, buccal, and lingual cortical regions of maxillary and mandibular edentulous arches were measured by a tomography machine. Mean bone density measurements were recorded in Hounsfield units. The data thus obtained from 10 sites of maxillary and mandibular arches were tabulated and analyzed using SPSS statistical software. This study showed no significant changes in bone density between the controlled diabetic and nondiabetic subjects. Within the limitation of this study, it can be concluded that bone density does not seem to be affected in controlled type II diabetics.

Plasma leptin and energy expenditure during prolonged, moderate intensity, treadmill exercise

BACKGROUND

Current literature shows conflicting results regarding the possible direct role of exercise on leptin concentrations, mainly because of a non-homogeneous level of energy expenditure (EE) and the lack of standardization of energy balance.

AIM

The aim of the study was to evaluate the effect of exercise duration and its corresponding EE on leptin levels, during prolonged treadmill exercise, in a well-controlled laboratory setting.

MATERIALS AND METHODS

Seven young trained males underwent a 4-h treadmill exercise. The starting intensity was set at 65% of maximal oxygen consumption. At the start of the test and throughout the exercise, venous blood samples were drawn for the assays of leptin, glucose, free fatty acids (FFA), cortisol, epinephrine (E) and norepinephrine (NE). Hourly and total EE was monitored with gas analysis.

RESULTS

Plasma leptin levels decreased from 1.10±0.15 to 0.85±0.26 μg/l (p<0.01) at the end of the exercise, reaching a significant reduction already after the second hour. FFA and cortisol showed a progressive significant increase, while glucose did not significantly change throughout the test. Plasma E and NE significantly increased at all sampling times compared to basal values (48.1±30.3 to 352.3±187.7 pg/ml, p<0.001 and 238.1±118.9 to 1798.7±413.5 pg/ml, p<0.001). The random-effects model for panel data analysis showed negative correlation between leptin, NE and the values of progressive EE (r2=0.745, p<0.05).

CONCLUSIONS

Our data demonstrate that, during a prolonged moderate intensity exercise, leptin decrease is significantly related to the total EE. Further, NE concentrations seem to play an important role in the inhibition of leptin secretion.

The relationship between hand osteoarthritis and serum leptin concentration in participants of the Third National Health and Nutrition Examination Survey

Introduction

Leptin has been suspected to contribute to the development of osteoarthritis (OA). However, this hypothesis has not been tested in large-scale hand OA cohorts. Our study aimed to determine whether there is a cross-sectional relationship between serum leptin levels and hand OA in a population-based sample of US adults.

Method

We used the Third National Health and Nutrition Examination Survey (NHANES III), a national cross-sectional population-based survey, to study the relationship between hand OA and serum leptin concentration. We applied previously established classification criteria for hand OA. Patients with rheumatoid arthritis were excluded. Potential confounders included sex, body mass index, the presence of polyarticular OA, diabetes, and total cholesterol. We estimated unadjusted mean leptin concentration by hand OA status and by all confounders. We further developed a linear regression model to assess mean leptin levels, adjusted for appropriate confounders.

Results

Of 2,477 subjects in the NHANES III sample that had a hand examination and did not have rheumatoid arthritis, 1,056 (42.6%) had a leptin measurement and were included in the analysis. Subjects with and without leptin measurement had similar demographic characteristics. We did not find any significant differences in mean serum leptin levels in subjects with symptomatic hand OA (7.38 ng/ml in males (95% confidence interval (CI) = 5.31, 9.46) and 21.55 ng/ml in females (95% CI = 17.08, 26.02)), asymptomatic hand OA (6.69 ng/ml in males (95% CI = 5.19, 8.18) and 17.09 ng/ml in females (95% CI = 15.00, 19.18)), and no hand OA (8.22 ng/ml in males (95% CI = 7.47, 8.97) and 20.77 ng/ml in females (95% CI = 18.01, 23.53)) in the unadjusted analysis. In a multivariable linear regression model that included variables of hand OA status, age, race/ethnicity, and obesity status, we found no statistically significant association between serum leptin and hand OA status.

Conclusions

In this cross-sectional study of a large representative US cohort, we did not find any evidence to support the hypothesis that serum leptin is associated with hand OA.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm²) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case–control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA_1C were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Effect of atorvastatin and fenofibric acid on adipokine release from visceral and subcutaneous adipose tissue of patients with mixed dyslipidemia and normolipidemic subjects

Because of methodological limitations and conflicting results of studies conducted thus far, the possible involvement of human adipose tissue in pleiotropic effects of statins and fibrates requires better understanding. Samples of visceral and subcutaneous adipose tissue obtained from 23 mixed dyslipidemic patients and 23 normolipidemic subjects were treated in vitro for 48 h with atorvastatin, fenofibric acid or both these agents. Visceral and subcutaneous fat of mixed dyslipidemic patients released more leptin, resistin, interleukin-6, tumor necrosis factor alpha (TNFalpha and plasminogen activator inhibitor-1 (PAI-1), and less adiponectin than respective adipose tissue of patients without lipid abnormalities. In both groups of patients, visceral and subcutaneous tissue varied in the amount of secreted adipokines. In dyslipidemic patients both drugs administered alone affected adipose tissue adiponectin and resistin secretion. Additionally, atorvastatin decreased PAI-1 while fenofibric acid reduced leptin release. A combined administration of atorvastatin and fenofibric acid changed the release of all studied markers by visceral fat but did not affect interleukin-6 and TNFalpha release by subcutaneous tissue. In normolipidemic subjects the effect on adipokine release was more pronounced in visceral fat, in which it was strongest if the drugs were given together. Adipose tissue hormonal activity differs between mixed dyslipidemic and normolipidemic patients and between visceral and subcutaneous adipose tissue. Atorvastatin and fenofibrate exhibit their pleiotropic effects in part by changing the adipokine release by human adipose tissue, regardless of its origin. These effects are stronger in patients with mixed dyslipidemia and are particularly pronounced if atorvastatin and fenofibric acid are given together.

Making circadian cancer therapy practical

Practical circadian therapy for the cancer patient involves 3 spheres of intervention-improving lifestyle, optimizing internal biochemical milieu, and adjusting treatment times. The potential value of improving overall circadian functioning is shown in the work of Mormont et al in which pronounced rest-activity rhythms were associated with better survival in colorectal cancer patients receiving chronomodulated chemotherapy. Lifestyle interventions that may improve circadian functioning involve diet, physical activity, and mind-body therapies. A diet that is anti-inflammatory and has appropriate carbohydrate intake, as well as regular meal timing, encourages normal circadian cycles. Adequate daytime physical activity encourages restful sleep, and morning light exposure during exercise may entrain melatonin rhythms. Meditation and other mind-body therapies can reduce anxiety and depression that may disrupt sleep. Aspects of the biochemical milieu that specifically disrupt circadian functioning are inflammation and stress hormones. Inflammation and cytokine disruption can be addressed with diet, herbs, and other natural substances. Chronomodulation of chemotherapy in a US clinical setting will be discussed. A series of 12 cases will be presented of patients who experienced grade 3 to 4 toxicities with various chemotherapy regimens for colorectal cancer. When rechallenged with the same regimens administered chronotherapeutically, none of the patients experienced grade 3 to 4 toxicity. Integrating all the above treatment modalities has the potential to improve both the quality of life and disease outcomes in cancer patients.

Fat as an endocrine organ: influence of exercise

The prevalence of diabetes and obesity continues to increase. It is therefore important to identify the pathophysiology underlying these disorders. An inability of insulin to stimulate glucose uptake, i.e., insulin resistance, appears to be a common link between diabetes and obesity. The identification of various adipocyte-secreted cytokines (adipocytokines) that influence satiety, energy balance, and insulin sensitivity provide a novel target for the treatment of these disorders. Adipocytokines are differentially expressed with obesity and diabetes, making them a strong candidate for linking insulin resistance to these pathological conditions. This review explores the role of adipocytokines in insulin action and examines the effect of exercise training on adipocytokine content.

Circadian phase difference of leptin in android versus gynoid obesity

A circadian rhythm in serum leptin, measured every 4 h for 24 h, characterizes normal-weight women (N = 14), and women with gynoid (N = 17) or android (N = 26) obesity, peaking around midnight (P < 0.05), but differing by about 3 h between android and gynoid women (P < 0.01). Obesity is associated with a higher MESOR (rhythm-adjusted mean; P < 0.001) and a smaller relative circadian amplitude (P < 0.05). Gynoid obesity is associated with a larger circadian amplitude of cortisol (P < 0.05), whereas android obesity is associated with a larger circadian amplitude and a higher MESOR of insulin (P < 0.05). Understanding putative mechanisms underlying different body fat distribution may lead to improved chronotherapeutic measures.

Plasma leptin and exercise: recent findings

It is established that plasma leptin is associated with satiety and that leptin stimulates lipid metabolism, and increases energy expenditure. These effects implicate leptin as a major regulator of energy homeostasis, which may serve to limit excess energy storage. As plasma leptin concentrations are tightly coupled with fat mass in humans, decreases in adipose mass with weight loss coincide with decreased concentrations of circulating leptin. However, due to many confounding factors, the effects of exercise on circulating leptin are less clear. The data from investigations examining single exercise bouts suggest that serum leptin concentrations are unaltered by short duration (41 minutes or less), non-exhaustive exercise, but may be affected by short duration, exhaustive exercise. More convincingly, studies investigating long duration exercise bouts indicate that serum leptin concentrations are reduced with exercise durations ranging from one to multiple hours. These findings raise speculation that exercise-associated reductions in leptin may be due to alterations in nutrient availability or nutrient flux at the level of the adipocytes, the primary site of leptin production and secretion. Thus, one purpose of this review is to discuss the effects of exercise on circulating leptin concentrations with special emphasis on studies that have examined single exercise bouts that are associated with high levels of energy expenditure and energy deficit. In addition, a 'nutrient sensing pathway' (the hexosamine biosynthetic pathway), which regulates leptin gene expression, will be discussed as a possible mechanism by which exercise-induced energy deficit may modulate serum leptin concentrations.

Plasma agouti-related protein level: a possible correlation with fasted and fed states in humans and rats

We measured plasma concentrations of agouti-related protein (AGRP) in humans and rats and determined whether these were affected by ingestion of a meal after fasting. In 17 healthy human subjects, the mean plasma concentration of AGRP was lower in the fed state than in the fasted state. Two hours after a breakfast meal, AGRP levels dropped by 39%. By contrast, a continued fast for 2 h increased the average AGRP concentration by 73%. In rats with diet-induced obesity, refeeding resulted in a 50% decrease in plasma AGRP concentrations following a fasting-refeeding protocol. Our results support the notion that plasma AGRP may serve as a biomarker for the transition from a fasted to the satiated state.

Glucocorticoid-induced osteopenia in the mouse as assessed by histomorphometry, microcomputed tomography, and biochemical markers

Glucocorticoids are potent anti-inflammatory molecules used in the treatment of asthma, rheumatoid arthritis, inflammatory bowel disease, and other inflammatory and dermatological diseases, as well as in posttransplantation immunotherapy. Although glucocorticoids have been prescribed for many years, their potential side effects, when administered orally, can prevent their long-term use. The most serious side effect observed in the clinic is glucocorticoid-induced osteoporosis (GIOP). To develop a small animal model to characterize glucocorticoid-induced bone loss, we carried out a series of experiments using BALB/c mice given daily intraperitoneal doses of the synthetic glucocorticoid, dexamethasone. Following dexamethasone treatment, the mice became osteopenic, with highly significant decreases in bone formation rate and mineral apposition rate, as assessed by standard histomorphometry. Moreover, 3 week treatment with dexamethasone resulted in a decrease in trabecular thickness and trabecular number with an increase in surface-to-volume ratio of trabeculae in the distal femur, as measured using microcomputed tomography (micro-CT). The serum bone formation marker, osteocalcin, was dose-dependently decreased in all mice treated with dexamethasone and showed a parallel extent of regulation to the bone formation rate changes. In addition, serum levels of leptin, recently identified as playing a role in the regulation of bone mass, increased following dexamethasone treatment. BALB/c mice therefore represent a useful model system in which the detrimental effects of glucocorticoids on bone can be studied.