Molecular Assessment of Proadipogenic Effects for Common-Use Contraceptives and Their Mixtures.

Hormonal contraceptives are widely prescribed due to their effectiveness and convenience and have become an integral part of family planning strategies worldwide. In the United States, approximately 65% of reproductive-aged women are estimated to be using contraceptive options, with approximately 33% using one or a combination of hormonal contraceptives. While these methods have undeniably contributed to improved reproductive health, recent studies have raised concerns regarding their potential effect on metabolic health. Despite widespread anecdotal reports, epidemiological research has been mixed as to whether hormonal contraceptives contribute to metabolic health effects. As such, the goals of this study were to assess the adipogenic activity of common hormonal contraceptive chemicals and their mixtures. Five different models of adipogenesis were used to provide a rigorous assessment of metabolism-disrupting effects. Interestingly, every individual contraceptive (both estrogens and progestins) and each mixture promoted significant adipogenesis (eg, triglyceride accumulation and/or preadipocyte proliferation). These effects appeared to be mediated in part through estrogen receptor signaling, particularly for the contraceptive mixtures, as cotreatment with fulvestrant acted to inhibit contraceptive-mediated proadipogenic effects on triglyceride accumulation. In conclusion, this research provides valuable insights into the complex interactions between hormonal contraceptives and adipocyte development. The results suggest that both progestins and estrogens within these contraceptives can influence adipogenesis, and the specific effects may vary based on the receptor disruption profiles. Further research is warranted to establish translation of these findings to in vivo models and to further assess causal mechanisms underlying these effects.

A comparative assessment of reference genes in mouse brown adipocyte differentiation and thermogenesis in vitro.

Adipogenic differentiation and thermogenesis in brown adipose tissue (BAT) undergo dynamic processes, altering phenotypes and gene expressions. Proper reference genes in gene expression analysis are crucial to mitigate experimental variances and ensure PCR efficacy. Unreliable reference genes can lead to erroneous gene expression quantification, resulting in data misinterpretation. This study focused on identifying suitable reference genes for mouse brown adipocyte research, utilizing brown adipocytes from the Ucp1-luciferase ThermoMouse model. Comparative analysis of gene expression data under adipogenesis and thermogenesis conditions was conducted, validating 13 housekeeping genes through various algorithms, including DeltaCq, BestKeeper, geNorm, Normfinder, and RefFinder. Tbp and Rer1 emerged as optimal references for Ucp1 and Pparg expression in brown adipogenesis, while Tbp and Ubc were ideal for the expression analysis of these target genes in thermogenesis. Conversely, certain conventional references, including Actb, Tubb5, and Gapdh, proved unstable as reference genes under both conditions. These findings stress the critical consideration of reference gene selection in gene expression analysis within specific biological systems to ensure accurate conclusions.

Caveolae-associated protein 3 promotes adipogenic differentiation of porcine preadipocytes by promoting extracellular signal-regulated kinase phosphorylation.

Fat deposition is one of the key factors affecting the economic development of pig husbandry. The aim of this study was to investigate the expression characteristics of caveolae-associated protein 3 (CAVIN3) and to elucidate its effect and mechanism on adipogenic differentiation of porcine preadipocytes. Cell transfection, quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot, and oil red O staining were used to detect the effect of CAVIN3 on the differentiation of porcine preadipocytes. The results showed that CAVIN3 was expressed in various tissues, with higher expression in adipose tissue, differentially expressed during cell adipogenic differentiation, and mainly distributed in the cytoplasm. Functional studies showed that, after CAVIN3 interference in preadipocytes, the expression of adipogenic factors and the content of lipid droplets were significantly decreased (p < 0.05). The results were reversed after CAVIN3 was overexpressed. The mechanism research showed that LY3214996 inhibited the extracellular signal-regulated kinase (ERK) phosphorylation and further inhibited lipogenic factors expression. Overexpression of CAVIN3 attenuates the inhibitory effect of LY3214996 on ERK phosphorylation and attenuates its inhibitory effect on adipogenic differentiation. Therefore, this study demonstrated that CAVIN3 promotes the differentiation of porcine preadipocytes by promoting ERK phosphorylation. The present study can lay a theoretical foundation for further studying the molecular mechanism of porcine fat deposition.

Discovery and functional assessment of a novel adipocyte population driven by intracellular Wnt/ß-catenin signaling in mammals.

Wnt/ß-catenin signaling has been well established as a potent inhibitor of adipogenesis. Here, we identified a population of adipocytes that exhibit persistent activity of Wnt/ß-catenin signaling, as revealed by the Tcf/Lef-GFP reporter allele, in embryonic and adult mouse fat depots, named as Wnt+ adipocytes. We showed that this ß-catenin-mediated signaling activation in these cells is Wnt ligand- and receptor-independent but relies on AKT/mTOR pathway and is essential for cell survival. Such adipocytes are distinct from classical ones in transcriptomic and genomic signatures and can be induced from various sources of mesenchymal stromal cells including human cells. Genetic lineage-tracing and targeted cell ablation studies revealed that these adipocytes convert into beige adipocytes directly and are also required for beige fat recruitment under thermal challenge, demonstrating both cell autonomous and non-cell autonomous roles in adaptive thermogenesis. Furthermore, mice bearing targeted ablation of these adipocytes exhibited glucose intolerance, while mice receiving exogenously supplied such cells manifested enhanced glucose utilization. Our studies uncover a unique adipocyte population in regulating beiging in adipose tissues and systemic glucose homeostasis.

Adipogenesis of ear mesenchymal stem cells (EMSCs): adipose biomarker-based assessment of genetic variation, adipocyte function, and brown/brite differentiation.

Ear mesenchymal stem cells (EMSCs) have been investigated to differentiate into adipocytes, chondrocytes, and muscle cells in vitro. However, the factors controlling adipogenesis of this stem cell population in vitro, function, and type of adipocytes raised from them are still unclear. Here we found that genetics have a modest effect on adipogenic capacity of EMSCs. Adipocytes differentiated from EMSCs have a potential function in lipid metabolism as indicated by expression of lipogenic genes and this function of EMSC adipocytes is regulated by genetics. EMSCs failed to be differentiated into brite/brown adipocytes due to their lack of a thermogenic program, but adipocytes raised from EMSCs showed a fate of white adipocytes. Overall, our data suggest that EMSCs differentiate into functional white adipocytes in vitro and this is genetic-dependent.

Adipocyte-specific deletion of PIP5K1c reduces diet-induced obesity and insulin resistance by increasing energy expenditure.

BACKGROUND: Phosphatidylinositol 4-phosphate 5-kinase type I c (PIP5K1c) catalyses the synthesis of phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) by phosphorylating phosphatidylinositol 4 phosphate, which plays multiple roles in regulating focal adhesion formation, invasion, and cell migration signal transduction cascades. Here, a new physiological mechanism of PIP5K1c in adipocytes and systemic metabolism is reported. METHODS: Adipose-specific conditional knockout mice were generated to delete the PIP5K1c gene in adipocytes. In addition, in vitro research investigated the effect of PIP5K1c deletion on adipogenesis. RESULTS: Deletion of PIP5K1c in adipocytes significantly alleviated high fat diet (HFD)-induced obesity, hyperlipidaemia, hepatic steatosis, and insulin resistance. PIP5K1c deficiency in adipocytes also decreased adipocyte volume in HFD-induced obese mice, whereas no significant differences were observed in body weight and adipose tissue weight under normal chow diet conditions. PIP5K1c knockout in adipocytes significantly enhanced energy expenditure, which protected mice from HFD-induced weight gain. In addition, adipogenesis was markedly impaired in mouse stromal vascular fraction (SVF) from PIP5K1c-deleted mice. CONCLUSION: Under HFD conditions, PIP5K1c regulates adipogenesis and adipose tissue homeostasis. Together, these data indicate that PIP5K1c could be a novel potential target for regulating fat accumulation, which could provide novel insight into the treatment of obesity.

Coelogin ameliorates metabolic dyshomeostasis by regulating adipogenesis and enhancing energy expenditure in adipose tissue.

Obesity and associated metabolic disorders are heading up with an alarming rate in developing nations. One of highly sought solution for metabolic disorders is to identify natural molecule with an ability to reduce obesity and increase insulin sensitivity. Coelogin (CLN) is a phenanthrene derivative isolated from the ethanolic extract of Coelogyne cristata. In our constant efforts to identify novel anti-dyslipidemic and anti-adipogenic compounds using CFPMA (common feature pharmacophore model using known anti-adipogenic compounds) model, predicted possible anti-adipogenic activity of CLN. In vitro results showed significant inhibition of adipogenesis in 3T3-L1 and C3H10T1/2 cell by CLN. It arrests the cell cycle in G1 phase of interphase and inhibits mitotic clonal expansion to regulate adipogenesis. CLN elicits insulin sensitizing effect in mature adipocytes. During extracellular flux assessment studies, it increases oxidative respiration and energy expenditure in adipocytes. In vivo, CLN reversed HFD-induced dyslipidemia as well as insulin resistance in C57BL/6 mice. It promoted the expression of genes involved in improved mitochondrial function and fatty acid oxidation in eWAT. CLN restored energy expenditure and increased the capacity of energy utilization in HFD fed mice. Taken together, the study indicated beneficial effects of CLN in combating obesity-associated metabolic complications.

Organophosphorus pesticides exert estrogen receptor agonistic effect determined using Organization for Economic Cooperation and Development PBTG455, and induce estrogen receptor-dependent adipogenesis of 3T3-L1 adipocytes.

Various chemicals containing pesticides can induce adipogenesis and cause obesity. Organophosphorus pesticides have been used for pest control. Here, we investigated the estrogen receptor (ER)-dependent adipogenesis-inducing effect of representative organophosphorus pesticides (OPs), diazinon, phoxim, terbufos and tolclofos-methyl in 3T3-L1 adipocytes. Four OPs exhibited ER agonistic effect, determined using the OECD Performance Based Test Guideline No. 455; in vitro ER stably transfected transactivation assay using ERα-HeLa-9903 cell line, through binding affinity to ERα. Additionally, they increased lipid droplet accumulation in a dose-dependent manner, which was suppressed by ICI182,780, a well-known ER antagonist. Four OPs treatment induced peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and perilipin expression. Furthermore, PPARγ, C/EBPα and perilipin expression was inhibited by co-treatment with ICI182,780. The increased mRNA expression of lipoprotein lipase and fatty acid synthase by four OPs was suppressed by co-treatment with ICI182,780. These results indicated that diazinon, phoxim, terbufos, and tolclofos-methyl might have adipogenesis-inducing effect mediated by interacting with ER.

In vitro assessment of anti-fibrotic drug activity does not predict in vivo efficacy in murine models of Duchenne muscular dystrophy.

AIM: Fibrosis is the most common complication from chronic diseases, and yet no therapy capable of mitigating its effects is available. Our goal is to unveil specific signaling regulating the fibrogenic process and to identify potential small molecule candidates that block fibrogenic differentiation of fibro/adipogenic progenitors. METHOD: We performed a large-scale drug screen using muscle-resident fibro/adipogenic progenitors from a mouse model expressing EGFP under the Collagen1a1 promotor. We first confirmed that the EGFP was expressed in response to TGFß1 stimulation in vitro. Then we treated cells with TGFß1 alone or with drugs from two libraries of known compounds. The drugs ability to block the fibrogenic differentiation was quantified by imaging and flow cytometry. From a two-rounds screening, positive hits were tested in vivo in the mice model for the Duchenne Muscular Dystrophy (mdx mice). The histopathology of the muscles was assessed with picrosirius red (fibrosis) and laminin staining (myofiber size). KEY FINDINGS: From the in vitro drug screening, we identified 21 drugs and tested 3 in vivo on the mdx mice. None of the three drugs significantly improved muscle histopathology. SIGNIFICANCE: The in vitro drug screen identified various efficient compounds, none of them strongly inhibited fibrosis in skeletal muscle of mdx mice. To explain these observations, we hypothesize that in Duchenne Muscular Dystrophy, in which fibrosis is a secondary event due to chronic degeneration and inflammation, the drugs tested could have adverse effect on regeneration or inflammation, balancing off any positive effects and leading to the absence of significant results.

A cost-effective three-dimensional culture platform functionally mimics the adipose tissue microenvironment surrounding the kidney.

There is an increasing interest in studying the crosstalk between tumor-associated adipose tissue and tumor progression. In proximity to the primary site of kidney tumors, perinephric adipose tissue has direct contact with cancer cells when kidney cancer becomes invasive. To mimic the perinephric adipose tissue microenvironment, we applied the liquid overlay-based technique, which cost-effectively generated functional adipocyte spheroids using mesenchymal stem cells isolated from human perinephric adipose tissue. Thereafter, we co-cultured adipocyte spheroids with unpolarized macrophages and discovered an M2 phenotype skew in macrophages. Moreover, we discovered that, in the presence of adipocyte spheroids, M2 macrophages exhibited stronger invasive capacity than M1 macrophages. We further showed that the perinephric adipose tissue sampled from metastatic kidney cancer exhibited high expression of M2 macrophages. In conclusion, the liquid overlay-based technique can generate a novel three-dimensional platform enabling investigation of the interactions of adipocytes and other types of cells in a tumor microenvironment.

A simple, efficient and economical method for isolating and culturing human umbilical cord blood­derived mesenchymal stromal cells.

Mesenchymal stromal cells (MSCs) hold broad therapeutic potential in various diseases, however, it is difficult to produce sufficient numbers of MSCs for clinical application, therefore, improved culture systems are required. The present study aimed to develop a novel method for isolating and culturing human umbilical cord blood­derived mesenchymal stromal cells (hUCB­MSCs). A sequential culture method was developed that uses two types of culture media to optimize the isolation and culture of hUCB­MSCs. First, DMEM supplemented with mesenchymal stem cell growth supplement was used to improve the colony formation and primary culture success rates of hUCB­MSCs. Then, after removing the heterogeneous cell population, ordinary DMEM was used from the fourth passage. This method obtained hUCB­MSCs with high culture efficiency and at a greatly reduced cost. The optimal culture conditions were determined and the hUCB­MSCs were phenotypically characterized after passaging. Taken together, this simple, efficient and economical method can produce a large number of high­quality hUCB­MSCs in <1 month, therefore facilitating the future clinical applications of hUCB­MSCs.

Assessment of adipogenic, antioxidant, and anti-inflammatory properties of whole and whey bovine colostrum.

Bovine colostrum (BC) has been used for nutraceutical purposes for animals and humans. Bovine colostrum is a complex heterogeneous product and its antimicrobial activity, antioxidant potential, and growth factors can vary depending on age and species of the cow as well as their environment. Bovine colostrum preparation in skimmed or whey fractions can also alter properties of BC. Our goal was to compare cumulative anti-inflammatory, antioxidant, and adipogenic properties of natural (whole) versus whey BC. We compared properties of whole and whey BC in 3T3-L1 preadipocytes permanently transfected with reporters responding to changes in inflammatory (NfκbRE/green fluorescent protein), anti-inflammatory (Nrf2/YFP), and adipogenic (Fabp4/cyan fluorescent protein) status in cells. Interleukin-6 secretion in these cells was measured by ELISA. Whole and whey BC induce IL-6 secretion from 3T3-L1 fibroblasts; however, whey preparation stimulated less IL-6 secretion. Cumulative inflammatory nuclear factor (NF)κB activation in the presence of lipopolysaccharide was reduced by both whole (-27%) and whey BC (-22%) compared with lipopolysaccharide-treated cells (100%). Treatment with whole BC was more effective in the reduction of NFκB activation compared with whey BC and occurred in a dose-dependent manner. In consonance with decreased NFκB activation, the Nrf2 promoter activity was also reduced in response to whole (-27%) and whey (-13%) treatments compared with nontreated cells (100%). Whole and whey BC suppressed adipogenesis, measured as induction of Fabp4, by -27 and -13%, respectively, compared with nontreated 3T3-L1 fibroblasts (100%). Our results showed distinct differences in properties of whey and whole BC that could be used to attain reduced adipogenic or cumulative inflammatory responses.

Complete Assessment of Multilineage Differentiation Potential of Human Skeletal Muscle-Derived Mesenchymal Stem/Stromal Cells.

The minimal criteria for mesenchymal stem/stromal cell (MSC) identification set by the International Society for Cellular Therapy include plastic adherence, presence and absence of a set of surface antigens and in vitro multilineage differentiation. This differentiation is assessed through stimulation of MSCs with defined combination and concentration of growth factors towards specific lineages and histological confirmation of the presence of differentiated cells. Here we provide protocols for multilineage differentiation, namely, osteogenesis, adipogenesis, chondrogenesis and myogenesis. We also provide their respective histological analyses.

Role of peroxisome proliferator-activated receptor gamma Pro12Ala polymorphism in human adipose tissue: assessment of adipogenesis and adipocyte glucose and lipid turnover.

The protective mechanisms of peroxisome proliferator-activated receptor gamma (PPARγ) Pro12Ala polymorphism in type 2 diabetes (T2D) are unclear. We obtained subcutaneous adipose tissue (AT) before and 3 h after oral glucose (OGTT) in carriers and non-carriers of the Ala allele (12 Pro/Pro, 15 Pro/Ala, and 13 Ala/Ala). Adipogenesis, adipocyte glucose uptake and lipolysis as well as PPARγ target gene expression were investigated and compared between the genotype groups. During fasting and post-OGTT, neither basal nor insulin-stimulated adipocyte glucose uptake differed between genotypes. Compared to fasting, a decreased hormone-sensitive lipase gene expression in Pro/Pro (p < 0.05) was accompanied with a higher antilipolytic effect of insulin post-OGTT (p < 0.01). The adipocyte size was similar across groups. Preadipocyte differentiation rates between Pro/Pro and Ala/Ala were unchanged. In conclusion, no major differences in AT differentiation, glucose uptake, lipolysis or expression of PPARγ target genes were observed between different PPARγ Pro12Ala genotypes. Albeit small, our study may suggest that other pathways in AT or effects exerted in other tissues might contribute to the Pro12Ala-mediated protection against T2D.

Comparative assessment of metal-specific adipogenic activity in zinc and vanadium-citrates through associated gene expression.

Diabetes mellitus comprises a group of metabolic abnormalities due to insulin deficiency and/or resistance. Obesity contributes to diabetes, with a strong causal relationship existing between diabetes and insulin resistance, especially in patients with Diabetes mellitus II. Adipocytes emerge as key constituents of adipose tissue physiology. In their pre-mature form to mature state transformation, adipocytes fully exemplify one of the key adipogenic actions of insulin. Poised to a) gain insight into adipogenesis leading to antidiabetic factors, and b) investigate adipogenesis through careful examination of insulin contributions to interwoven mechanistic pathways, a systematic comparative study was launched involving well-defined metal-citrates (zinc and vanadium), the chemical reactivity of which was in line with their chemistry under physiological conditions. Selection of the specific compounds was based on their common aqueous coordination chemistry involving the physiological chelator citric acid. Cellular maturation of pre-adipocytes to their mature form was pursued in the presence-absence of insulin and employment of closely linked genetic targets, key to adipocyte maturation (Peroxisome proliferator-activated receptor gamma (PPAR-γ), Glucose transporter 1,3,4 (GLUT 1,3,4), Adiponectin (ADIPOQ), Glucokinase (GCK), and Insulin receptor (INS-R)). The results show a) distinct adipogenic biological profiles for the metalloforms involved in a dose-, time- and nature-dependent manner, and b) metal ion-specific adipogenic response-signals at the same or higher level than insulin toward all selected targets. Collectively, the foundations have been established for future exploitation of the distinct metal-specific adipogenic factors contributing to the functional maturation of adipose tissue and their use toward hyperglycemic control in Diabetes mellitus.

Loss of P2X7 receptor function dampens whole body energy expenditure and fatty acid oxidation.

The established role of ATP-responsive P2X7 receptor in inflammatory, neurodegenerative, and immune diseases is now expanding to include several aspects of metabolic dysregulation. Indeed, P2X7 receptors are involved in ß cell function, insulin secretion, and liability to diabetes, and loss of P2X7 function may increase the risk of hepatic steatosis and disrupt adipogenesis. Recently, body weight gain, abnormal lipid accumulation, adipocyte hyperplasia, increased fat mass, and ectopic fat distribution have been found in P2X7 KO mice. Here, we hypothesized that such clinical picture of dysregulated lipid metabolism might be the result of altered in vivo energy metabolism. By indirect calorimetry, we assessed 24 h of energy expenditure (EE) and respiratory exchange ratio (RER) as quotient of carbohydrate to fat oxidation in P2X7 KO mice. Moreover, we assessed the same parameters in aged-matched WT counterparts that underwent a 7-day treatment with the P2X7 antagonist A804598. We found that loss of P2X7 function elicits a severe decrease of EE that was less pronounced in A804598-treated mice. In parallel, P2X7KO mice show a drastic increase of RER, thus indicating the occurrence of a greater ratio of carbohydrate to fat oxidation. Decreased EE and fat oxidation is predictive of body weight gain, which was here confirmed. Taken together, our data provide evidence that P2X7 loss of function produces defective energy homeostasis that, together with disrupted adipogenesis, might help to explain accumulation of adipose tissue and contribute to disclose the potential role of P2X7 in metabolic diseases.

Antidiabetic Naphthoquinones and Their Plant Resources in Thailand.

Diabetes mellitus is the seventh leading cause of death globally. Ninety percent of the diabetic population suffers from type-2 diabetes, which still needs an effective, safe and economical oral hypoglycemic therapy. Plants are rich sources of various therapeutic molecules. More than 400 medicinal plants of interesting phytochemical diversity have been reported for their antidiabetic potential. Naphthoquinones are a group of phytochemicals, which have a wide range of pharmacological potential, including antidiabetic activity. Naphthoquinones exert their antidiabetic effects through various mechanisms such as the inhibition of α-glucosidase and protein tyrosine phosphatase 1B, increased glucose uptake in myocytes and adipocytes via glucose transporter type 4 (GLUT4) and GLUT2 translocations, enhanced peroxisome proliferator-activated receptor gamma (PPARγ) ligand activity, and by normalizing carbohydrate metabolizing enzymes in the liver. Moreover, naphthoquinone inhibits adipogenesis by both upstream and downstream regulation to control obesity, which is one of the important risk factors for diabetes. Naturally occurring naphthoquinones, as well as their plant sources, are therefore of interest for exploring their antidiabetic potential. The present review aims to overview the antidiabetic potential of naphthoquinones and their plant resources in Thailand.

Hmox1 promotes osteogenic differentiation at the expense of reduced adipogenic differentiation induced by BMP9 in C3H10T1/2 cells.

Mesenchymal stem cells (MSCs) are multipotent progenitors that can differentiate into a variety of cell types under proper stimuli. Bone morphogenetic protein 9 (BMP9) is able to simultaneously induce both adipogenic and osteogenic differentiation of MSCs although the regulatory molecules involved remain to be fully identified and characterized. Heme oxygenase 1 (Hmox1) plays an essential role not only in fat metabolism, but also in bone development. In the present study, we investigated the functional role of Hmox1 in BMP9-induced osteogenic/adipogenic differentiation in MSCs line C3H10T1/2 and probed the possible mechanism involved. We found that BMP9 promoted the endogenous expression of Hmox1 in C3H10T1/2 cells. Overexpression of Hmox1 or cobalt protoporphyrin (CoPP), an inducer of Hmox1, increased BMP9-induced osteogenic differentiation in vitro. Subcutaneous stem cell implantation in nude mice further confirmed that Hmox1 potentiated BMP9-induced ectopic bone formation in vivo. In contrast, Hmox1 reduced BMP9-induced adipogenic differentiation in C3H10T1/2 cells. Although had no obvious effect on BMP9-induced Smad1/5/8 phosphorylation, Hmox1 enhanced phosphorylation of p38, and AKT, while decreased phosphorylation of ERK1/2. Furthermore, Hmox1 increased total ß-catenin protein level, and promoted the nuclear translocation of ß-catenin in C3H10T1/2 cells. Taken together, our study strongly suggests that Hmox1 is likely to potentiate osteogenic differentiation and yet decrease adipogenic differentiation induced by BMP9 possibly through regulation of multiple signaling pathways.

Cellular Mechanisms Driving Sex Differences in Adipose Tissue Biology and Body Shape in Humans and Mouse Models.

Sex differences in adipose tissue distribution and the metabolic, endocrine, and immune functions of different anatomical fat depots have been described, but they are incompletely documented in the literature. It is becoming increasingly clear that adipose depots serve distinct functions in males and females and have specific physiological roles. However, the mechanisms that regulate the size and function of specific adipose tissues in men and women remain poorly understood. New insights from mouse models have advanced our understanding of depot differences in adipose growth and remodeling via the proliferation and differentiation of adipose progenitors that can expand adipocyte number in the tissue or simply replace dysfunctional older and larger adipocytes. A limited ability of a depot to expand or remodel can lead to excessive adipocyte hypertrophy, which is often correlated with metabolic dysfunction. However, the relationship of adipocyte size and function varies by depot and sex. For example, femoral adipose tissues of premenopausal women appear to have a greater capacity for adipose expansion via hyperplasia and hypertrophy; although larger, these gluteal-femoral adipocytes remain insulin sensitive. The microenvironment of specific depots, including the composition of the extracellular matrix and cellular composition, as well as cell-autonomous genetic differences, influences sex- and depot-dependent metabolic and growth properties. Although there are some species differences, studies of the molecular and physiological determinants of sex differences in adipocyte growth and function in humans and rodents are both needed for understanding sex differences in health and disease.