Insulin in combination with pioglitazone prevents advanced cachexia in 256-Walker tumor-bearing rats: effect is greater than treatment alone and is associated with improved insulin sensitivity

BACKGROUND

Insulin (INS) resistance and hypoinsulinemia commonly observed in cancer-carrying, can contribute to cachexia. However, the effects of INS and INS sensitizers, such as pioglitazone (PIO), particularly when used in combination therapy, on cancer cachexia have not been evaluated sufficiently. We investigated the effects of INS and PIO, at various doses, either isolated or combined, on cachexia in Walker-256 tumor-bearing rats (TB rats).

METHODS

INS or INS + PIO were administered in TB rats, for 6 or 12 days, starting from the day of tumor cells inoculation.

RESULTS

INS at 18 or 27 U/kg (12-days treatment), but not 9 U/kg, reduced fat loss and slightly prevented weight loss. However, INS 18 U/kg + PIO 5, 10, 20, or 40 mg/kg (6 or 12-day treatment) reduced fat loss and markedly prevented weight loss but did not affect muscle wasting. While TB rats lost weight (37.9% in 12 days), TB rats treated with INS 18 U/kg + PIO 5 mg/kg showed pronounced weight gain (73.7%), which was greater than the sum (synergism) of the weight gains promoted by isolated treatments with INS 18 U/kg (14.7%) or PIO 5 mg/kg (13.1%). The beneficial effect of the INS 18 U/kg + PIO 5 mg/kg on weight loss was associated with improved INS sensitivity, as indicated by the higher blood glucose clearance constant (kITT), decreased levels of free fatty acids and triacylglycerols (INS resistance-inducing factors) in the blood, and increased expression of p-Akt (INS signaling pathway protein) in adipose tissue.

CONCLUSIONS

The combined treatment with INS 18 U/kg + PIO 5 mg/kg was more effective in preventing advanced cachexia in TB rats than each treatment alone, emerging as the best approach, considering the lower dosage and higher efficacy. This combination completely preserved adipose mass and markedly reduced weight loss through a synergistic mechanism linked to improved insulin sensitivity. These findings provide new insights into the importance of drug combinations in effectively combating fat loss in advanced cachexia.

The effectiveness of high-intensity interval training on body composition of rodent models of obesity: A systematic review and meta-analysis

The present systematic review was compiled to analyze the effectiveness of High-intensity interval training (HIIT) protocols on the body composition of rodents with obesity. Databases were searched until February 2021 for experimental trials in rodents with a minimum duration of four weeks of HIIT and endpoints associated with obesity. The data were analyzed by meta-analysis performed for comparisons of body composition. Sensitivity analysis was performed to investigate the consistency of individual researches. Of all of the 524 studies found, only 14 were included. The analysis showed a significant reduction in body weight ([CI 95%: -8.35; -1.98] P ≤ 0.01), adiposity index ([IC 95%: -1.04; -0.80] P ≤ 0.01), and fat pads ([IC 95%: -0.59; -0.06] P ≤ 0.01). HIIT performed on treadmill or water was effective to reduce body weight (P < 0.05). In conclusion, HIIT attenuated both body weight and adiposity induced either by HFD (high-fat diet) or by GOM (genetic obese model), thereby inducing positive changes in body composition.

Concurrent training remodels the subcutaneous adipose tissue extracellular matrix of people living with HIV: a non-randomized clinical trial

Evaluate the effect of 12wks of concurrent training (CT) in extracellular matrix (ECM) of subcutaneous adipose tissue (SAT) in people living with HIV/aids (PLWHA). To the non-randomized clinical trial 19 participants, 11 healthy (HIV-) and 18 PLWHA under the use of highly active antiretroviral therapy (HAART) for at least 1 year (HIV+). All participants engaged in a moderate-intensity CT program for 12 weeks, three times a week. Before and after CT, aerobic and strength performance were assessed, as well as anthropometry and biochemical blood profile. Also, SAT biopsies were carried out for histologic and morphometric analysis. The statistical analysis was carried out with R Studio, using descriptive and inferential analysis, ANOVA test and mixed-effect model were utilized (P<0.05). HIV+ showed higher levels of VLDL, TGL, and lower levels of HDL in baseline than HIV- (P<0.05). All groups improved aerobic and strength performance (P<0.05). Both groups presented reduced adipocyte sizes after CT (P<0,05). Lastly, HIV+ presented smaller adipocytes and higher elastic fiber deposition in baseline and decreased after training only in HIV+, matching similarly to HIV- group. Thus, CT in PLWHA promoted a decrease in size heterogeneity of adipocytes and elastic fiber deposition, remodeling ECM and improving SAT fibrosis profile. Brazilian Clinical Trials Registry (UTN: U1111-1214-3022) Novelty • Adipose tissue fibrosis is improved by training in people living with HIV. • Concurrent training remodels adipose tissue extracellular matrix.

Effects of exercise modality and intensity on the CD4 count in people with HIV: a systematic review and meta-analysis

The purpose of this study was to assess the effect of training modality and exercise intensity on the modulation of lymphocytes CD4 count in people living with HIV (PLWH). A search for randomised controlled trials was performed using five databases (PubMed/Medline, Cochrane, LILACS, Scielo and CAPES). Meta-analyses of mean differences (MD) were conducted using a random-effects model to compare the effects of training modality and intensity on CD4 count. The CD4 count comparing physical training vs. control group (MD of CD4 was 54.58 cell/ml³ [CI 95% 15.58-93.59], p =< 0.01). In according to the subgroup analysis, only aerobic exercise has proved to have a significant effect on CD4 (MD 79.91 cell/ml³ [CI 95% 19.30-140.52], p =< 0.01). When exercise intensities were stratified, only intense training proved to have a significant effect on CD4 (MD 64.87 cell/ml³ [CI 95% 15.79-113.95], p =< 0.01). In meta-regression analysis showed that the aerobic training, as well, high the intensity training were predictors significant to the improvement of CD4 (p =< 0.01). Exercise training is an important strategy to assist in the treatment of PLWH. The aerobic training modality and the high intensity training were able to promote improve the modulation of CD4 count chronically in PLWH.

Resistance exercise training induces subcutaneous and visceral adipose tissue browning in Swiss mice

Aerobic exercise training (AER) may promote several adaptations in white adipose tissue (WAT), including a phenotypic change known as browning. The present study aimed at assessing if resistance exercise training (RES) would be as efficient as AER in inducing a brown-like adipocyte reprogramming in WAT. Thirty Swiss male mice were randomly divided into 3 groups with 10 animals each: 1) sedentary (SED), 2) AER, and 3) RES. After the adaptation training, an incremental test was performed at the beginning of each week to adjust training load. Mice were submitted to 8 wk of AER or RES. After the experimental period, inguinal and retroperitoneal WAT (iWAT and rpWAT) and brown adipose tissue (BAT) were collected. The prescription of AER and RES was effective in increasing the performance of both groups. Also, RES presented a lower body weight than AER/SED. AER and RES reduced the area of iWAT and rpWAT adipocytes and the lipid area of BAT, induced an increase of vascular endothelial growth factor (VEGF) and cluster of differentiation 31 (CD31) and uncoupling protein 1 (UCP-1), and increased the expression of selective genes of brown and beige phenotype in adipocytes after 8 wk. In general, we demonstrated here that AER and RES training similarly induced the browning of iWAT and rpWAT.NEW & NOTEWORTHY Aerobic exercise training (AER) induces the browning of white adipose tissue, turning adipocytes multilocular, highly vascularized and expressing uncoupling protein 1 (UCP-1). The current study compared the efficiency of resistance to aerobic exercise training to promote a brown-like phenotype. Our results suggest that both types of training similarly induce subcutaneous and visceral adipose tissue browning.

Adverse effects of chronic treatment with the Main subclasses of highly active antiretroviral therapy: a systematic review

OBJECTIVES

The aim of the review was to elucidate the adverse effects of chronic treatment with the main subclasses of highly active antiretroviral therapy (HAART).

METHODS

A systematic review was carried out using the methods recommended in the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P). Searches of articles in MEDLINE, SCIELO, Web of Science and LILACS were conducted from January to October 2018 based on the following descriptors and keywords: 'HIV' [AND]; 'AIDS' [OR]; 'HAART' [AND]; 'Highly Active Antiretroviral Therapy' [OR]; 'Adverse Effects' [AND]. All articles selected described the biochemical changes produced by, and the main adverse effects of, using one or more of the following HAART subclasses: nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and other new drugs. The selected articles included patients living with HIV (PLWH) initiating or continuing any type of HAART. The results are presented qualitatively and discussed.

RESULTS

Twenty-one articles found in the searches were selected for the review, and they included a total of 5626 participants. Seven of the studies investigated mainly NRTIs, three studies mainly NNRTIs, eight studies predominantly PIs, and three studies other antiretroviral drugs as the main treatment. The most common adverse effects on biochemical parameters were the emergence of anaemia for NRTIs as well as NNRTIs and PIs, and plasma lipid alterations caused by their prolonged use. In general, it was found that biological differences among individuals can cause differences in adverse effects, such as virological and treatment failure.

CONCLUSIONS

One or more occurrences of adverse effects of the chronic utilization of drugs were found for all subclasses of HAART, and certain combinations of drugs from different subclasses were also found to be associated with adverse events.

LLC tumor cells-derivated factors reduces adipogenesis in co-culture system

Cancer cachexia (CC) is a multifactorial syndrome with an unknown etiology. The primary symptom is the progressive reduction of the body weight. Recently, down-regulation of adipogenic and lipogenic genes were demonstrated to be early affected during cachexia progression in adipose tissue (AT), resulting in AT remodeling. Thus, this study aimed to evaluate in a co-culture system the influence of the Lewis Lung Carcinoma (LLC) tumor cells (c/c-LLC) in an established pre-adipocyte cell line 3T3-L1 adipogenic capacity. c/c-LLC in the presence of 3T3-L1 caused a reduction in lipids accumulation, suggesting that secretory tumor cells products may affect adipogenesis. Interestingly, a very early (day 2) down-regulation of proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), followed by late genes (day 4 and 8), adiponectin, perilipin, and fatty acid-binding protein 4 (FABP4). Caspase-3 expression was increased on the last day of cell differentiation; it occurred in the expression of pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α). Overall, our results suggest that LLC secretory products impair adipocyte differentiation in a co-culture system and increased apoptosis. In summary, our study has shown the inhibition of the adipogenic process in the 3T3-L1 co-culture system with LLC cells.

Effect of combined training on body composition and metabolic variables in people living with HIV: A randomized clinical trial

PURPOSE

The aim of this study was to conduct a randomized clinical trial to assess the effects of 16 weeks of combined training on body composition, lipid profile, adiponectin, C-reactive protein (CRP), and leptin levels in people living with HIV/AIDS (PLWHA).

METHODS

Fifty-eight HIV-infected individuals were randomized into a training group (T) or a control group (C). Combined training consisted of aerobic and resistance exercises performed at the same training session, applied at a frequency of three times a week for a total of 16 weeks. Waist circumference, body mass, body fat percentage (%fat), fat mass, lipid profile, adiponectin, CRP, and leptin levels were measured pre- and post-training in both groups.

RESULTS

Sixteen weeks of combined training decreased (P < 0.05) body fat in different body segments in PLWHA. Lipodystrophic PLWHA experienced greater reduction in body fat in the android region than non-lipodystrophic PLWHA after combined training. Lipid profile and circulating levels of adiponectin, leptin, and CRP remained unchanged.

CONCLUSIONS

Sixteen weeks of combined training was effective to reduce body fat in different body segments, without altering plasma lipid and cytokine levels.

Exercise improves cytokine profile in HIV-infected people: A randomized clinical trial

PURPOSE

Verify the effects of concurrent training on cytokines in people living with HIV under antiretroviral therapy (ART) treatment.

METHODS

This was a blinded, parallel-group, clinical trial, where 49 participants, divided in two groups, either control group or concurrent training group, took part in the intervention. The control group performed recreational activities and concurrent training group participated of 16-week, 3 times per week of heart rate guided-aerobic plus resistance training for major muscular groups. Cytokines (interleukins 4, 5, 6, 8, 10, tumor necrosis factor-α, interferon-γ, and granulocyte-macrophage colony-stimulating factor) were measured before and after 16-week experimental period using flow cytometry.

RESULTS

From 49 participants who took part in the intervention, 28 completed the program and had data analyzed. There was a significant interaction for IL-8, which increased for control group: 7.1±5.1 vs. 8.1±6.0 and a decrease for concurrent training: 8.0±4.4 vs. 5.4±2.3. In addition, magnitude-based inference showed a likely beneficial effect for the training group when compared to the control group for IL-8, IL-5, and IL-10. The difference perceptual: mean and [CI 90%] between delta of difference within groups was -43.1 [-64.0 to -10.0] and -6.6 [-14.7 to 2.3], respectively.

CONCLUSION

Short-term exercise is able to decrease the levels of IL-5, IL-8, and IL-10 in HIV-infected people undergoing ART.

RESPOSTAS AGUDAS DO EXERCÍCIO FÍSICO EM PESSOAS INFECTADAS PELO HIV: UMA REVISÃO SISTEMÁTICA

RESUMO O treinamento físico é uma estratégia importante para a saúde de pessoas que vivem com HIV/AIDS; contudo, suas respostas a curto prazo ainda não foram amplamente estudadas, o que limita o entendimento dos efeitos e da segurança da prescrição do treinamento para essa população. Portanto, objetivou-se revisar sistematicamente as respostas agudas decorrentes do exercício físico em pessoas com HIV sobre variáveis fisiológicas e imunológicas. Para isso, foi realizada uma revisão sistemática a partir de trabalhos indexados nas seguintes bases de dados: Medline, Lilacs, Scielo, Web of Science e Science Direct. Os descritores utilizados foram: acquired immunodeficiency syndrome, HIV, AIDS, seropositive, acute session, short, physical activity, exercise, training. As buscas foram realizadas em fevereiro de 2015 e atualizadas em dezembro de 2015 e foram conduzidas sem restrição de datas de publicação ou idioma específico. Foram incluídos para esta revisão artigos que avaliaram as respostas agudas decorrentes de algum modelo de prescrição de treinamento físico envolvendo exercícios aeróbicos, com pesos ou combinados (exercícios aeróbicos e com pesos) relacionados com variáveis fisiológicas e imunológicas em pessoas infectadas pelo HIV. Foram encontrados 2.422 títulos, dos quais, após exclusão das duplicatas e a aplicação dos critérios de elegibilidade, foram selecionados sete artigos para síntese qualitativa. De acordo com os resultados reportados pelos estudos há evidências de que, imediatamente após a realização do exercício físico, ocorre um aumento do número de células circulantes, incluindo leucócitos totais, neutrófilos, monócitos e linfócitos T CD8+ em pessoas infectadas pelo HIV. Além disso, também se observaram alterações significantes nas concentrações de lactato, triglicerídeos, epinefrina e norepinefrina imediatamente após a realização do treinamento aeróbico, independentemente do uso de TARV e/ou de hiperlactatemia. No entanto, não há evidências suficientes para afirmar que o treinamento físico seja totalmente seguro e eficaz para esta população.

Creatine supplementation in trained rats causes changes in myenteric neurons and intestinal wall morphometry

Creatine is widely used by athletes as an ergogenic resource. The aim of this study was to evaluate the influence of creatine supplementation on the duodenum of rats submitted to physical training. The number and myenteric neuronal cell bodies as well mucosal and muscular tunic morphometry were evaluated. Control animals received a standard chow for 8 weeks, and the treated ones received the standard chow for 4 weeks and were later fed with the same chow but added with 2% creatine. Animals were divided in groups: sedentary, sedentary supplemented with creatine, trained and trained supplemented with creatine. The training consisted in treadmill running for 8 weeks. Duodenal samples were either processed for whole mount preparations or for paraffin embedding and hematoxylin-eosin staining for histological and morphometric studies of the mucosa, the muscular tunic and myenteric neurons. It was observed that neither creatine nor physical training alone promoted alterations in muscular tunic thickness, villus height or crypts depth, however, a reduction in these parameters was observed when both were associated. The number of myenteric neurons was unchanged, but the neuronal cell body area was reduced in trained animals but not when training and creatine was associated, suggesting a neuroprotector role of this substance.

Heterogeneous time-dependent response of adipose tissue during the development of cancer cachexia

Cancer cachexia induces loss of fat mass that accounts for a large part of the dramatic weight loss observed both in humans and in animal models; however, the literature does not provide consistent information regarding the set point of weight loss and how the different visceral adipose tissue depots contribute to this symptom. To evaluate that, 8-week-old male Wistar rats were subcutaneously inoculated with 1 ml (2×10(7)) of tumour cells (Walker 256). Samples of different visceral white adipose tissue (WAT) depots were collected at days 0, 4, 7 and 14 and stored at -80 °C (seven to ten animals/each day per group). Mesenteric and retroperitoneal depot mass was decreased to the greatest extent on day 14 compared with day 0. Gene and protein expression of PPARγ2 (PPARG) fell significantly following tumour implantation in all three adipose tissue depots while C/EBPα (CEBPA) and SREBP-1c (SREBF1) expression decreased over time only in epididymal and retroperitoneal depots. Decreased adipogenic gene expression and morphological disruption of visceral WAT are further supported by the dramatic reduction in mRNA and protein levels of perilipin. Classical markers of inflammation and macrophage infiltration (f4/80, CD68 and MIF-1α) in WAT were significantly increased in the later stage of cachexia (although showing a incremental pattern along the course of cachexia) and presented a depot-specific regulation. These results indicate that impairment in the lipid-storing function of adipose tissue occurs at different times and that the mesenteric adipose tissue is more resistant to the 'fat-reducing effect' than the other visceral depots during cancer cachexia progression.

Adipose tissue inflammation and cancer cachexia: possible role of nuclear transcription factors

Cancer cachexia is a multifaceted syndrome whose aetiology is extremely complex and is directly related to poor patient prognosis and survival. Changes in lipid metabolism in cancer cachexia result in marked reduction of total fat mass, increased lipolysis, total oxidation of fatty acids, hyperlipidaemia, hypertriglyceridaemia, and hypercholesterolaemia. These changes are believed to be induced by inflammatory mediators, such as tumour necrosis factor-α (TNF-α) and other factors. Attention has recently been drawn to the current theory that cachexia is a chronic inflammatory state, mainly caused by the host's reaction to the tumour. Changes in expression of numerous inflammatory mediators, notably in white adipose tissue (WAT), may trigger several changes in WAT homeostasis. The inhibition of adipocyte differentiation by PPARγ is paralleled by the appearance of smaller adipocytes, which may partially account for the inhibitory effect of PPARγ on inflammatory gene expression. Furthermore, inflammatory modulation and/or inhibition seems to be dependent on the IKK/NF-κB pathway, suggesting that a possible interaction between NF-κB and PPARγ is required to modulate WAT inflammation induced by cancer cachexia. In this article, current literature on the possible mechanisms of NF-κB and PPARγ regulation of WAT cells during cancer cachexia are discussed. This review aims to assess the role of a possible interaction between NF-κB and PPARγ in the setting of cancer cachexia as well as its significant role as a potential modulator of chronic inflammation that could be explored therapeutically.

Adipocyte differentiation is inhibited by melatonin through the regulation of C/EBPbeta transcriptional activity

Considering that melatonin has been implicated in body weight control, this work investigated whether this effect involves the regulation of adipogenesis. 3T3-L1 preadipocytes were induced to differentiate in the absence or presence of melatonin (10(-3) m). Swiss-3T3 cells ectopically and conditionally (Tet-off system) over-expressing the 34 kDa C/EBPbeta isoform (Swiss-LAP cells) were employed as a tool to assess the mechanisms of action at the molecular level. Protein markers of the adipogenic phenotype were analyzed by Western blot. At 36 hr of differentiation of 3T3-L1 preadipocytes, a reduction of PPARgamma expression was detected followed by a further reduction, at day 4, of perilipin, aP2 and adiponectin protein expression in melatonin-treated cells. Real-time PCR analysis also showed a decrease of PPARgamma (60%), C/EBPalpha (75%), adiponectin (30%) and aP2 (40%) mRNA expression. Finally, we transfected Swiss LAP cells with a C/EBPalpha gene promoter/reporter construct in which luciferase expression is enhanced in response to C/EBPbeta activity. Culture of such transfected cells in the absence of tetracycline led to a 2.5-fold activation of the C/EBPalpha promoter. However, when treated with melatonin, the level of C/EBPalpha promoter activation by C/EBPbeta was reduced by 50% (P = 0.05, n = 6). In addition, this inhibitory effect of melatonin was also reflected in the phenotype of the cells, since their capacity to accumulate lipids droplets was reduced as confirmed by the poor staining with Oil Red O. In conclusion, melatonin at a concentration of 10(-3 ) m works as a negative regulator of adipogenesis acting in part by inhibiting the activity of a critical adipogenic transcription factor, C/EBPbeta.

Melatonin and the circadian entrainment of metabolic and hormonal activities in primary isolated adipocytes

The aim of this work was to investigate the effect of the in vitro circadian-like exposure to melatonin [in the presence or absence of insulin (Ins)] on the metabolism and clock gene expression in adipocytes. To simulate the cyclic characteristics of the daily melatonin profile, isolated rat adipocytes were exposed in a circadian-like pattern to melatonin added to the incubating medium for 12 hr (mimicking the night), followed by an equal period without melatonin (mimicking the day) combined or not with Ins. This intermittent incubation was interrupted when four and a half 24-hr cycles were fulfilled. At the end, either during the induced night (melatonin present) or the induced day (melatonin absent), the rates of lipolysis and D-[U-(14)C]-glucose incorporation into lipids were estimated, in addition to the determination of lipogenic [glucose-6-phosphate dehydrogenase and fatty acid synthase (FAS)] and lipolytic (hormone sensitive lipase) enzymes and clock gene (Bmal-1b, Clock, Per-1 and Cry-1) mRNA expression. The leptin release was also measured. During the induced night, the following effects were observed: an increase in the mRNA expression of Clock, Per-1 and FAS; a rise in lipogenic response and leptin secretion; and a decrease in the lipolytic activity. The intermittent exposure of adipocytes to melatonin temporally and rhythmically synchronized their metabolic and hormonal function in a circadian fashion, mimicking what is observed in vivo in animals during the daily light-dark cycle. Therefore, this work helps to clarify the physiological relevance of the circadian pattern of melatonin secretion and its interactions with Ins, contributing to a better understanding of the adipocyte biology.

Melatonin enhances leptin expression by rat adipocytes in the presence of insulin

Leptin and melatonin play an important role in the regulation of body mass and energy balance. Both hormones show a circadian rhythm, with increasing values at night. In addition, melatonin receptors were recently described in adipocytes, where leptin is synthesized. Here, we investigated the influence of melatonin and its interaction with insulin and dexamethasone on leptin expression. Isolated rat adipocytes were incubated with melatonin (1 nM) alone or in combination with insulin (5 nM) and/or dexamethasone (7 nM) for 6 h. Melatonin or insulin alone did not affect leptin expression, but together they increased it by 120%. Dexamethasone increased leptin mRNA content (105%), and this effect was not enhanced by melatonin. Simultaneous treatment with the three hormones provoked a further increase in leptin release (250%) and leptin mRNA (100%). Melatonin prevented the forskolin-induced inhibition (95%) of leptin expression. In addition, melatonin's ability to stimulate leptin release (in the presence of insulin) was completely blocked by pertussis toxin and luzindole. To gain further insight into the molecular basis of melatonin and insulin synergism, the insulin-signaling pathway was investigated. Melatonin increased the insulin-induced insulin receptor-beta tyrosine phosphorylation, which led to an increased serine phosphorylation of the downstream convergent protein Akt. We concluded that melatonin interacts with insulin and upregulates insulin-stimulated leptin expression. These effects are caused by melatonin binding to the pertussis toxin-sensitive G(i) protein-coupled membrane receptor (MT1 subtype) and the cross talk with insulin, since insulin receptor and its convergent target Akt are coactivated by melatonin.

Pinealectomy alters adipose tissue adaptability to fasting in rats

This study investigated the effects of pinealectomy and fasting on rat adipose tissue metabolism, as well as on profiles of the hormones directly involved in its regulation (insulin, leptin, and corticosterone). Pinealectomized (PINX) and sham-operated (CONTROL) adult male Wistar rats were killed 6 weeks after surgery, in either fed or fasted (12 and 36 hours) states. Blood samples (for glucose and hormone determinations) and peri-epididymal adipocytes (for in vitro insulin-stimulated glucose uptake, oxidation, and incorporation into lipids) were collected. Pineal ablation decreased insulin-stimulated glucose uptake in adipocytes of both fed and fasted animals without affecting insulin-binding capacity. Pinealectomy attenuated the reduction in the ability to oxidize glucose in both basal and insulin-stimulated states during fasting. This alteration in the ability of adipocytes to oxidize glucose appeared together with a decrease in insulin-induced glucose incorporation into lipids in PINX animals. Additionally, pinealectomized rats showed higher corticosterone levels in both fed and fasted states, and a lower leptinemia with 36 hours of fasting, in comparison to CONTROLs. In conclusion, our data reinforce the hypothesis that the pineal gland has a role in the modulation of adipocyte metabolism, and its absence alters metabolic adaptation to fasting in rats.