Combination of Capsaicin and Hesperidin Reduces the Effectiveness of Each Compound To Decrease the Adipocyte Size and To Induce Browning Features in Adipose Tissue of Western Diet Fed Rats.

We explored the potential of hesperidin and capsaicin, separately and in combination, to induce white adipose tissue (WAT) browning and to help body weight management in Western diet-fed rats. Adult male Wistar rats were fed for 8 weeks with Western diet and treated daily with hesperidin (100 mg/kg/day), capsaicin (4 mg/kg/day), hesperidin (100 mg/kg/day) + capsaicin (4 mg/kg/day), or the vehicle. Hesperidin and capsaicin separately, but not (or to a lesser extent) the combination, resulted in a decreased size of adipocytes and induced emergence of multilocular brown-like adipocytes positive for UCP1 and CIDEA in retroperitoneal WAT. Expression levels of browning markers, such as Prdm16, in inguinal WAT also increased with capsaicin treatment compared with the vehicle (145% ± 17% vs 92% ± 21%, P < 0.05), but no significant effects were found with the combination (106% ± 12%). Thus, the combination of both bioactives reduces the effectiveness of each compound to decrease the adipocyte size and induce WAT browning.

Leptin Intake at Physiological Doses Throughout Lactation in Male Wistar Rats Normalizes the Decreased Density of Tyrosine Hydroxylase-Immunoreactive Fibers in the Stomach Caused by Mild Gestational Calorie Restriction.

Introduction: Gestational under nutrition in rats has been shown to decrease expression of sympathetic innervation markers in peripheral tissues of offspring, including the stomach. This has been linked to lower gastric secretion and decreased circulating levels of ghrelin. Considering the critical role of leptin intake during lactation in preventing obesity and reversing adverse developmental programming effects, we aimed to find out whether leptin supplementation may reverse the above mentioned alterations caused by mild gestational calorie restriction. Methods: Three groups of male rats were studied at a juvenile age (25 days old) and during adulthood (3 and 6 months old): the offspring of ad libitum fed dams (controls), the offspring of dams that were diet restricted (20%) from days 1 to 12 of gestation (CR), and CR rats supplemented with a daily oral dose of leptin (equivalent to 5 times the average amount they could receive each day from maternal milk) throughout lactation (CR-Leptin). The density of TyrOH-immunoreactive (TyrOH+) fibers and the levels of Tyrosine hydroxylase (TyrOH)-used as potential markers of functional sympathetic innervation-were measured in stomach. Plasma leptin and ghrelin levels were also determined. Results: Twenty five-day-old CR rats, but not CR-Leptin rats, displayed lower density of TyrOH+ fibers (-46%) and TyrOH levels (-47%) in stomach compared to controls. Alterations in CR animals were mitigated at 6 months of age, and differences were not significant. Adult CR-Leptin animals showed higher plasma ghrelin levels than CR animals, particularly at 3 months (+16%), and a lower leptin/ghrelin ratio (-28 and -37% at 3 and 6 months, respectively). Conclusion: Leptin intake during lactation is able to reverse the alterations in the density of TyrOH+ fibers in the stomach and normalize the increased leptin/ghrelin ratio linked to a mild gestational calorie restriction in rats, supporting the relevance of leptin as an essential nutrient during lactation.

Gender-Associated Impact of Early Leucine Supplementation on Adult Predisposition to Obesity in Rats.

Early nutrition plays an important role in development and may constitute a relevant contributor to the onset of obesity in adulthood. The aim of this study was to evaluate the long-term impact of maternal leucine (Leu) supplementation during lactation on progeny in rats. A chow diet, supplemented with 2% Leu, was supplied during lactation (21 days) and, from weaning onwards, was replaced by a standard chow diet. Then, at adulthood (6 months of age), this was replaced with hypercaloric diets (either with high-fat (HF) or high-carbohydrate (HC) content), for two months, to induce obesity. Female offspring from Leu-supplemented dams showed higher increases in body weight and in body fat (62%) than their respective controls; whereas males were somehow protected (15% less fat than the corresponding controls). This profile in Leu-females was associated with altered neuronal architecture at the paraventricular nucleus (PVN), involving neuropeptide Y (NPY) fibers and impaired expression of neuropeptides and factors of the mTOR signaling pathway in the hypothalamus. Interestingly, leptin and adiponectin expression in adipose tissue at weaning and at the time before the onset of obesity could be defined as early biomarkers of metabolic disturbance, predisposing towards adult obesity under the appropriate environment.

Pectin supplementation in rats mitigates age-related impairment in insulin and leptin sensitivity independently of reducing food intake.

SCOPE: This study investigates whether pectin supplementation in adult rats can ameliorate age-associated disturbances in peripheral insulin and leptin actions. METHODS AND RESULTS: Seven-month-old male Wistar rats were divided into three groups: control (rats fed ad libitum a standard-diet), pectin (rats fed ad libitum a standard-diet supplemented with 10% pectin), and pair-fed (rats pair-fed to the pectin group). They were sacrificed after 1 month. Pectin and pair-fed rats showed lower body weight gain and food intake than controls and underwent a decrease in leptin levels and an increase in adiponectin levels. Pectin-treated animals, but not pair-fed ones, showed lower body-fat content and HOMA-IR index after dietary intervention. Compared to controls, pectin-treated rats showed a decline in the expression of genes related to energy uptake (WAT) and lipogenesis (WAT and liver), and increased expression levels of lipolysis- and fatty-acid oxidation-related genes (liver). Some of the changes were not evidenced in the pair-fed group. These effects appear to be associated with improved leptin signaling. CONCLUSION: Ten percent pectin supplementation for 1 month in adult rats decreases body-fat content and ameliorates age-related insulin and leptin resistance more intensely than what could be attributed to the decrease in energy intake, overall contributing to better metabolic health.

Blood cell transcriptomic-based early biomarkers of adverse programming effects of gestational calorie restriction and their reversibility by leptin supplementation.

The challenge of preventing major chronic diseases requires reliable, early biomarkers. Gestational mild undernutrition in rats is enough to program the offspring to develop later pathologies; the intake of leptin, a breastmilk component, during lactation may reverse these programming effects. We used these models to identify, in peripheral blood mononuclear cells (PBMCs), transcriptomic-based early biomarkers of programmed susceptibility to later disorders, and explored their response to neonatal leptin intake. Microarray analysis was performed in PBMCs from the offspring of control and 20% gestational calorie-restricted dams (CR), and CR-rats supplemented with physiological doses of leptin throughout lactation. Notably, leptin supplementation normalised 218 of the 224 mRNA-levels identified in PBMCs associated to undernutrition during pregnancy. These markers may be useful for early identification and subsequent monitoring of individuals who are at risk of later diseases and would specifically benefit from the intake of appropriate amounts of leptin during lactation.

Oral leptin treatment in suckling rats ameliorates detrimental effects in hypothalamic structure and function caused by maternal caloric restriction during gestation.

A poor prenatal environment brings about perturbations in leptin surge and hypothalamic circuitry that program impaired ability to regulate energy homeostasis in adulthood. Here, using a rat model of moderate maternal caloric restriction during gestation, we aimed to investigate whether leptin supplementation with physiological doses throughout lactation is able to ameliorate the adverse developmental malprogramming effects exerted in offspring hypothalamus structure and function. Three groups of male and female rats were studied: the offspring of ad libitum fed dams (controls), the offspring of 20% calorie restricted dams during the first part of pregnancy (CR), and CR rats supplemented with physiological doses of leptin throughout lactation (CR-Leptin). Animals were sacrificed on postnatal day 25. Morphometric and immunohistochemical studies on arcuate (ARC) and paraventicular (PVN) nucleus were performed and hypothalamic expression levels of selected genes were determined. In CR males, leptin treatment restored, at least in part, the number of immunoreactive neuropeptide Y (NPY(+)) cells in ARC, the total number of cells in PVN, hypothalamic NPY, cocaine- and amphetamine-regulated transcript (CART) and suppressor of cytokine signalling-3 (SOCS-3) mRNA levels, and plasma leptin levels, which were decreased in CR animals. CR-Leptin males showed higher hypothalamic long-form leptin receptor (ObRb) mRNA levels, compared to control and CR animals. In CR females, leptin treatment reverted the increased number of cells in ARC and cell density in ARC and PVN, and reduced hypothalamic SOCS-3 mRNA expression to levels similar to controls. Leptin treatment also reverted the increased relative area of NPY(+) fibers in the PVN occurring in CR animals. In conclusion, leptin supplementation throughout lactation is able to revert, at least partly, most of the developmental effects on hypothalamic structure and function caused by moderate maternal caloric restriction during gestation, and hence making this metabolic malprogramming reversible to some extent.

Maternal dietary fat affects milk fatty acid profile and impacts on weight gain and thermogenic capacity of suckling rats.

We aimed to assess the effects of maternal supplementation with the main fat sources used in the human Western diet (olive oil, butter, margarine) on milk FA composition and on plasma FA profile of offspring, and to determine whether it may influence body-weight-gain (BWG) and adiposity of offspring during the suckling period. Wistar rats were supplemented with the different fat sources from day 14 of gestation and throughout lactation. Olive oil-supplemented dams showed the highest proportion of oleic-acid in milk, with no changes in plasma. Their offspring also showed the highest proportion of this FA in plasma, lower BWG during the suckling period, and higher levels of UCP1 in brown adipose tissue (BAT) at weaning. Margarine-supplemented dams showed the highest percentage of PUFA in milk, and a similar tendency was found in plasma of their offspring. Butter-supplemented dams displayed higher proportion of saturated FA (SFA) in milk compared to other fat-supplemented dams, but lower than controls. Control offspring also showed higher proportion of SFA in plasma and greater BWG during the suckling period than fat-supplemented groups. Significant correlations were found between the relative content of some milk FA and BWG of offspring, in particular, oleic-acid levels correlated negatively with BWG and positively with UCP1 levels. These results show that maternal dietary source of fat affects milk FA composition and circulating FA profile, as could be expected, but also BWG and thermogenic capacity of offspring during the suckling period. An effect of oleic-acid stimulating BAT thermogenic capacity of suckling pups is proposed.

Metabolic programming of sirtuin 1 (SIRT1) expression by moderate energy restriction during gestation in rats may be related to obesity susceptibility in later life.

In rats, 20% gestational energy restriction programmes offspring for higher food intake, which in adulthood results in higher body weight in males but not in females. Here, we aimed to assess whether the effects of moderate energy restriction during gestation and the sex-related outcomes on adult body weight may be related to the metabolic programming of sirtuin expression in different tissues. For this purpose, 25-d-old offspring of control and 20% energy-restricted (ER) rats (from days 1-12 of pregnancy) were studied. Body weight and the weight of white adipose tissue (WAT) depots and liver were recorded and mRNA expression of sirtuin 1 (SIRT1) and selected genes in the WAT, liver, muscle and hypothalamus were analysed. No differences were found in body weight or the weight of WAT and liver between the control and ER animals. A similar pattern of SIRT1 mRNA expression was found in the WAT, liver and skeletal muscle of ER animals, but in a sex-dependent manner: ER males showed lower SIRT1 mRNA levels than the controls, while no differences were found in females. A sex-different pattern was also observed in the hypothalamus. ER males, but not females, also showed lower mRNA levels of adipose TAG lipase (ATGL) and uncoupling protein 2 in WAT and of sterol response element binding protein 1c and stearoyl-CoA desaturase-1 in the liver. Both sexes of ER animals showed lower mRNA levels of 5' adenosine monophosphate-activated protein kinase and ATGL in the liver. In conclusion, moderate maternal energy restriction during gestation programmes a particular, sex-dependent gene expression profile of SIRT1 in different peripheral tissues, which may be related to obesity predisposition in adulthood; therefore SIRT1 expression emerges as a potential early biomarker of obesity susceptibility.

Maternal supplementation with an excess of different fat sources during pregnancy and lactation differentially affects feeding behavior in offspring: putative role of the leptin system.

SCOPE: This study investigates the lasting effects of maternal supplementation with different fat sources during pregnancy and lactation on feeding behavior and energy homeostasis of their offspring, and its relation to hypothetical effects in the development of main central structures involved in leptin signaling. METHODS AND RESULTS: Offspring of dams supplemented with olive oil, butter, or margarine during late pregnancy and lactation were fed with normal fat (NF) diet until 4-month-old, and then with NF or high fat (HF) diet until 6-month-old. Results showed that 21-day-old margarine group pups presented a higher cell number in the arcuate nucleus (ARC) (females) and higher hypothalamic ObRb/SOCS3 mRNA ratio (males). In adulthood, and under HF diet, they displayed a lower body weight (both genders) and body fat (males) than the butter group, a lower preference for fat food (both genders), and lower leptin levels than the olive oil (both genders) and butter (males) groups. CONCLUSIONS: Maternal supplementation with different fat sources during the perinatal period may affect the development of hypothalamic structures and hence predisposition to obesity. Margarine, compared with other fats, may program the offspring for increased leptin sensitivity and a lower preference for fat food, thus providing relative protection against body weight gain in adulthood, particularly under an obesogenic environment.

Impaired insulin and leptin sensitivity in the offspring of moderate caloric-restricted dams during gestation is early programmed.

We aimed to assess the mechanisms responsible for hyperphagia and metabolic alterations caused by maternal moderate caloric restriction during gestation. Male and female offspring of control and 20% caloric-restricted rats (CR) were studied. They were fed a normal-fat diet until 4 months of age and then moved to a high-fat diet until 6 months of age. Blood parameters and expression of selected genes in hypothalamus, retroperitoneal white adipose tissue (rWAT) and liver were analyzed at 25 days and 6 months of age. Plasma leptin was measured during suckling. Levels of proteins involved in insulin and leptin signaling were determined at 6 months of age. CR ate more calories than controls, but only males gained more weight. A peak in plasma leptin was found in 9-day-old controls, but was absent in CR. Twenty-five-day-old CR showed lower insulin receptor mRNA levels in hypothalamus, rWAT and liver, and long-form leptin receptor (ObRb) in hypothalamus. At the age of 6 months, homeostatic model assessment for insulin resistance index was higher in CR than controls, and CR males also displayed hyperleptinemia. Adult CR also showed lower ObRb mRNA levels in the hypothalamus (only females, but both showed altered neuropeptide Y/proopiomelanocortin mRNA ratio), rWAT and liver (males), and a decrease of protein kinase C zeta levels in rWAT (females) and liver (males) and of phosphorylated signal transducer and activator of transcription 3 in liver (females). These results suggest that CR animals are programmed for insulin and central leptin resistance, which may explain the dysregulation of appetite and other metabolic alterations, favoring obesity development, although only manifested in males. These early programming effects could be associated with the absence of leptin surge during lactation.

The different satiating capacity of CHO and fats can be mediated by different effects on leptin and ghrelin systems.

Leptin and ghrelin are known to be the main hormones involved in the control of food intake, with opposite effects. Here we aimed to assess whether changes in leptin and ghrelin systems can be involved in the different satiating capacities of carbohydrates (CHO) and fat. Adult male Wistar rats were studied under 24h fasting conditions and after 24h fasting followed by a 12h re-feeding period with 64 kcal of CHO or fat, consisting of a mixture of wheat starch and sucrose or bacon, respectively. Serum levels of leptin and ghrelin, and mRNA levels of leptin and ObRb in the retroperitoneal and inguinal adipose tissue and of NPY, POMC, ObRb and GSHR in the hypothalamus were measured. CHO re-feeding resulted in higher leptin mRNA expression levels in the retroperitoneal adipose tissue and in higher circulating leptin levels compared with those after fat re-feeding. Moreover, circulating ghrelin levels and ghrelin/leptin ratio were significantly higher after fat re-feeding compared with CHO re-feeding, and hypothalamic expression levels of ghrelin receptor increased after fat, but not after CHO, re-feeding. Hence, expression levels of hypothalamic neuropeptides involved in food intake control and regulated by these hormones, particularly the orexigenic NPY and the anorexigenic pro-opiomelanocortin (POMC)-derived alpha-melanocyte-stimulating hormone, were also differently affected by CHO and fat re-feeding, resulting in a significantly lower NPY/POMC ratio after CHO re-feeding than after fat re-feeding. In conclusion, different effects on the leptin and ghrelin systems can account, at least in part, for the lower satiating capacity of fat compared to CHO.

Effects of beta-carotene supplementation on adipose tissue thermogenic capacity in ferrets (Mustela putorius furo).

We previously described that the intake of pharmacological doses of beta-carotene (BC) resulted in higher body weight gain in the ferret (Mustela putorius furo), an animal model that resembles human subjects in terms of intestinal BC absorption and metabolism. These results were some way unexpected considering the condition of BC as a vitamin A precursor and the previous data in rodents showing these compounds as thermogenic activators. Here, we aimed to characterise in the ferret whether the mentioned changes in body weight could be explained by changes in adipose tissue thermogenic capacity. We studied the effects of 6-month supplementation with BC (0.8 and 3.2 mg/kg per d) on adipose tissue morphology and uncoupling protein-1 (UCP1) content. BC supplementation resulted in higher body weight (the high dose), induced depot- and dose-dependent hypertrophy of white adipocytes, decreased the amount of brown-like multilocular adipocytes in the retroperitoneal depot and decreased UCP1 content in different fat depots. To ascertain whether BC effects could be mediated by retinoic acid (RA), 1 week supplementation with RA (0.25 and 25 mg/kg per d) was also studied. RA treatment resulted in a slight decrease in adiposity, decreased cell lipid accumulation and increased UCP1 content, suggesting that the effects of BC on thermogenic capacity are not through RA. In conclusion, RA, but not BC, may have in the ferret comparable effects with those described in rodents, whereas differences concerning BC and RA treatments may be attributable to the different BC metabolism in the present animal model with a lower conversion of BC to RA compared with rodents.

Induction of NPY/AgRP orexigenic peptide expression in rat hypothalamus is an early event in fasting: relationship with circulating leptin, insulin and glucose.

Hypothalamus is crucial in the control of energy intake and expenditure in mammals, presenting two interconnected populations of neurons producing orexigenic NPY/AgRP (neuropeptide Y; agouti related peptide) and anorexigenic POMC/CART (pro-opiomelanocortin; cocaine and amphetamine regulated transcript) neuropeptides. We aimed to shed more light on the response and sensitivity in the production of these neuropeptides to face nutritional changes, particularly food deprivation, and on the signals that regulate them. Male Wistar rats were fasted for 0, 4, 8 and 24h and refed for 3h after 8h fasting. mRNA levels of gastric and adipose tissue (retroperitoneal, mesenteric and inguinal) leptin, and of hypothalamic NPY, AgRP, POMC, CART, leptin receptor, SOCS3 (suppressor of cytokine signaling 3) and insulin receptor were analyzed. Gastric and circulating leptin, and circulating insulin, glucose and ghrelin were also determined. The only neuropeptide mRNAs that responded (increasing) to the short-term periods of fasting used were those of NPY (transiently) and AgRP, and these changes were accompanied by an increase in leptin receptor mRNA levels and by a decrease in adipose and gastric leptin expression and in the circulating levels of leptin, insulin and glucose, but without changes in circulating ghrelin. The elevation in AgRP and leptin receptor mRNA levels and the drop in circulating leptin were not reverted with refeeding. It is suggested that the induction of expression of the orexigenic molecules in NPY/AgRP neurons is an early event upon fasting, related with changes in leptin, insulin and glucose levels, but with the role of leptin signaling in particular.

Sex-associated differences in the leptin and ghrelin systems related with the induction of hyperphagia under high-fat diet exposure in rats.

Leptin and ghrelin are known to be main hormones involved in the control of food intake, with opposing effects. Here we have explored whether changes in the leptin and ghrelin system are involved in the long-term effects of high-fat (HF) diet feeding in rats and whether sex-associated differences exist. Male and female Wistar rats were fed until the age of 6 months with a normal-fat (NF) or an HF-diet. Food intake and body weight were followed. Gastric and serum levels of leptin and ghrelin, and mRNA levels of leptin (in stomach and adipose tissue), ghrelin (in stomach), and NPY, POMC, and leptin and ghrelin receptors (OB-Rb and GHS-R) (in the hypothalamus) were measured. In both males and females, total caloric intake and body weight were greater under the HF-diet feeding. In females, circulating ghrelin levels and leptin mRNA expression in the stomach were higher under HF-diet. HF-diet feeding also resulted in higher hypothalamic NPY/POMC mRNA levels, more marked in females, and in lower OB-Rb mRNA levels, more marked in males. In addition, in females, serum ghrelin levels correlated positively with hypothalamic NPY mRNA levels, and these with caloric intake. In males, hypothalamic OB-Rb mRNA levels correlated positively with POMC mRNA levels and these correlated negatively with caloric intake and with body weight. These data reflect differences between sexes in the effects of HF-diet feeding on food intake control systems, suggesting an impairment of the anorexigenic leptin-POMC system in males and an over-stimulation of the orexigenic ghrelin-NPY system in females.

Effect of calcium-enriched high-fat diet on calcium, magnesium and zinc retention in mice.

The aim of this work was to assess the effects of a high-fat diet enriched in Ca, which accompanies lower body fat deposition, on mineral depots, as well as to assess the potential role of adaptive thermogenesis in mice. Male mice were fed ad libitum a high-fat (43 %) diet with a Ca content of 4 g/kg from calcium carbonate (control group) or 12 g/kg (42 % from milk powder and the rest from calcium carbonate) (Ca group) for 56 d. Body weight, food intake and urine were periodically collected. Tissue samples were collected when the mice were killed and the composition was determined. Expression of uncoupling proteins was determined by Western blotting. Mineral content was measured by flame atomic absorption spectrometry. Lower body weight gain and fat accretion was found in the Ca group. This could not be attributable to lower gross energy intake or to activation of adaptive thermogenesis. Although significant urine mineral loss was found in the Ca group, preservation of mineral depots in bone was observed. Our data support the fact that adding more Ca to the diet, using a combination of calcium carbonate plus milk powder containing among other things higher Zn and Mg, contributes to counteracting obesity and improving lipid metabolism.

Adiponectin is involved in the protective effect of DHEA against metabolic risk in aged rats.

The aim of the present work was to analyze the effect of dehydroepiandrosterone (DHEA) on several metabolic risk factors, including cardiovascular health and insulin resistance, in aged rats submitted to a high-fat diet. For that, weaned rats were fed on a high-fat diet until 20 months of age. In the last 13 weeks of life, a group (n=11) received the diet supplemented with DHEA (0.5%, w/w), serving the rest (n=10) as controls. Body weight, body fat, serum lipids (triglycerides, total cholesterol and non-esterified fatty acids (NEFA)), HOMA index, n-6/n-3 polyunsaturated fatty acid (PUFA) ratios, serum adiponectin, leptin, resistin and TNF-alpha, as well as adiponectin expression in adipose tissue, were measured. A stepwise discriminant test was used to analyze these variables, and an index of overall metabolic risk was generated from them. DHEA treatment resulted in a significantly lower overall metabolic risk index, as generated by the discriminant test (P<0.01). The DHEA group had lower body fat and n-6/n-3 polyunsaturated fatty acid (PUFA) ratios than the control group (P<0.01), and the same trends were observed for serum cholesterol, triglycerides and HOMA index; in contrast, adiponectin expression in adipose tissue increased in DHEA-treated rats (P<0.05). The discriminant analysis revealed that adiponectin, both from serum and adipose tissue, was the most influencing factor, followed by n-6/n-3 ratios in adipose tissue, and by body fat. Our results then suggest that adiponectin is involved in the protective effect of DHEA against metabolic risk demonstrated in the present work.

Effects of 6-month daily supplementation with oral beta-carotene in combination or not with benzo[a]pyrene on cell-cycle markers in the lung of ferrets.

Epidemiological studies have demonstrated that people who eat more fruits and vegetables (rich in carotenoids) and people who have higher serum beta-carotene (BC) levels have a lower risk of cancer, particularly lung cancer. However, the two main human intervention studies of BC supplementation (the ATBC and the CARET trials) revealed an increased risk of lung cancer among smokers and asbestos workers. Previous studies carried out in the ferret have reported that BC effects are related to dose. Here, we treated ferrets with two concentrations of oral BC (0.8 and 3.2 mg/kg body weight per day) for 6 months, using BC in a formulation also containing dl-alpha-tocopherol and ascorbyl palmitate. The effect of the smoke-derived carcinogenic agent benzo[a]pyrene (BP), with or without low-dose BC, was also analysed. We determined the protein levels and mRNA expression levels of activator protein 1 (c-Jun and c-Fos), c-Myc, cyclin D1, proliferating cellular nuclear antigen and retinoic acid receptor beta. We did not find higher levels of cell proliferation markers in the lung of ferrets treated with BC or signals of squamous metaplasia lesions either. On the other hand, although no evident signals of pulmonary carcinogenesis were observed in animals exposed to BP, BC supplementation in these animals may prevent against excess cell proliferation, since this reestablishes Jun protein and cyclin D1 mRNA levels in the lung of BP-exposed animals. In summary, these results show that the combination of BC with alpha-tocopherol and ascorbyl palmitate does not induce pro-oxidant effects in the lung of ferrets.

Morphology of ferret subcutaneous adipose tissue after 6-month daily supplementation with oral beta-carotene.

Adipose tissue is an important retinoid depot and retinoids are known to influence white and brown adipocyte metabolism. Identifying nutrients that can affect the biological activity of the adipose organ would be of great medical interest in the light of the current obesity epidemic and related disorders in developed countries. The vast majority of mammal studies of chronic administration of oral beta-carotene have used murine models, while few have employed mammals exhibiting uptake and processing of intestinal beta-carotene similar to those of humans. While rodents transform practically all ingested beta-carotene into retinol, in ferrets, as in humans, part of the beta-carotene is absorbed and released into the circulation intact. We studied the effects of 6-month daily administration of two doses of oral beta-carotene (0.8 or 3.2 mg/kg/day) on ferret body weight, size of body fat depots, and, using morphological and morphometric methods, on subcutaneous (inguinal) white adipose tissue (WAT). Because of the oral mode of administration, liver, stomach, and small and large intestine were also studied. Control animals received the vehicle. Data show that at the end of treatment the higher dose induced significantly higher body weight compared with controls and significantly higher inguinal fat depot compared with animals treated with the lower dose. In addition, chronic treatment with beta-carotene induced a dose-dependent hypertrophy of white adipocytes and increased neoangiogenesis in subcutaneous WAT in all treated ferrets. Vasculogenesis was independent of adipocyte hypertrophy. We also found focally evident liver steatosis in the ferrets treated with the higher dose of beta-carotene. The other gastrointestinal tract organs studied were not significantly different from those of control animals.

Gastric leptin: a putative role in the short-term regulation of food intake.

The discovery of the production of leptin by the stomach, in addition to its production by adipose tissue, has initiated new investigation into the possible role of this protein in the digestive physiology, in particular in the short-term control of energy balance. Leptin has been identified in the lower half of the stomach glands both in the pepsinogen granules of chief cells and in the granules of a specific endocrine cell type, suggesting that leptin action is exerted by both exocrine and endocrine pathways. Gastric leptin is sensitive to the nutritional state, being rapidly mobilized in response to food intake following fasting, or after the administration of satiety factors; this suggests a role for this protein in the short-term regulation of feeding, acting in collaboration with satiety peptides such as cholecystokinin. Leptin, produced by gastric cells and by adipocytes, could act on both acute and chronic regulation of feeding behaviour respectively, giving information to the brain on the availability of external (food) and internal (fat depots) energy resources, thus participating in short- and long-term satiation.