Ostarine does not enhance the metabolic effect of exercise in obese rats.

Overweight and obesity are associated with severe metabolic disorders and an increased risk of cardiovascular diseases. It is a known fact that physical activity has a positive effect on metabolic parameters, and also reduces the risk of diseases such as diabetes. Some products can enhance the rate of lipolysis and help in improving fat loss. One of these are selective androgen receptor modulators (SARMs) which act as anabolic agents and are also believed to aid in fat-burning. In this study, we investigated whether 30 days of ostarine administration could potentially improve metabolic parameters using the rat model of obesity combined with exercise. We assessed the levels of biochemical and hormonal parameters in serum samples as well as insulin sensitivity indices of tissues. There were significant changes in the metabolic parameters with exercise. However, we did not find any additive effects of ostarine and exercise on most of the parameters tested. Similar results were obtained from the analysis of gene expression and the concentration of leptin and adiponectin. Our results indicated that ostarine had a lowering effect on cholesterol concentration in the serum (P<0.05). Moreover, when combining ostarine and exercise, additive changes were only observed in the levels of total and HDL cholesterol. No significant change was observed in the metabolic parameters of obese rats with the use of ostarine at the dose of 0.4 mg/kg body weight. Since ostarine is known to enhance performance, further research on its effects is needed.

The first insight into black soldier fly meal in brown trout nutrition as an environmentally sustainable fish meal replacement.

Insect meals are considered among the most promising feed materials in fish nutrition due to their sustainability and possibility of fish meal replacement. The present study is the first application of full-fat black soldier fly larvae (BSFL) meal in brown trout (Salmo trutta m. fario) diets. Two experiments were performed on 240 brown trout fingerlings (average body mass 4.85 g) distributed into four groups (12 tanks for the growth performance experiment, 10 fish/tank; and 12 metabolic tanks for the digestibility test, 10 fish/tank). The experimental group design was conducted as follows: control diet, with no BSFL and 35% fish meal, and experimental diets: BSFL5 - with 5% BSFL full-fat meal and 32.5% fish meal; BSFL10 - with 10% BSFL full-fat meal and 30% fish meal; and BSFL20 - with 20% BSFL full-fat meal and 25% fish meal. No effects were recorded in the case of growth performance and feed utilization parameters. The environmental sustainability of the usage of insect meals in fish diets was proven - due to the lower fish meal inclusion, the fish-in-fish-out ratio decreased by 31% in BSFL20. In the case of the viscerosomatic index, increases in BSFL5 and BSFL20 were reported. In all experimental groups, decreases in hepatosomatic index values were observed. Crude protein digestibility decreased in BSFL5 and BSFL20, while crude fat digestibility decreased only in the BSFL20 group. The effect of including BSFL full-fat meal in a brown trout diet on serum biochemical parameters was reported. The aspartate transaminase concentration increased in BSFL10 and BSFL20, while the gamma-glutamyl transpeptidase values decreased in BSFL20. In the case of total cholesterol, higher values were observed in BSFL10 and BSFL20. The albumin content decreased in the BSFL20 group, while globulin showed the highest values in the control group. The microbiota composition was not affected by insect meal inclusion. In conclusion, the results of the present study showed the high potential of BSFL full-fat meal application of up to 20% in a brown trout diet.

Effect of obesity and hypothyroidism on hepcidin concentration in pregnancy - a pilot study using maternal and umbilical cord blood at delivery day.

Hepcidin is a primary regulator of iron metabolism in the human body. By promoting ferroportin degradation, hepcidin reduces intestinal iron absorption and its release from intracellular stores. In the course of pregnancy, gradually declining hepcidin concentrations encourage placental iron transfer, thereby providing the appropriate amount of iron for fetal development. Hence, we aimed to investigate changes in maternal and cord blood hepcidin and iron metabolism parameters in normal-weight (n=17) and obese (n=17) gestating women, as well as gravid women with a history of hypothyroidism following the restoration of euthyroidism (n=17). All blood samples were taken on the day of delivery, and ELISA kits were used for measurements. A significant increase in maternal hepcidin concentration was observed in obese pregnant women, compared to normal-weight controls (29.53±4.20 ng/mL vs. 25.69±5.70 ng/mL; P<0.05). However, only a slight, insignificant tendency for lower hepcidin was noted in the hypothyroid group, compared to the healthy controls (23.10±6.00 ng/mL vs. 25.69±5.70 ng/mL; P=NS). Moreover, decreased maternal free triiodothyronine, triiodothyronine, free thyroxine, and ferritin levels were revealed in the hypothyroid group, compared to the normal-weight individuals (P<0.05). Furthermore, positive correlations between maternal hepcidin and the majority of maternal thyroid hormones were found, with a most potent relation to FT3 (r=0.40; P<0.01). Interestingly, no alterations of thyroid hormones and iron metabolism parameters were noticed in cord blood in any of the subgroups. In summary, pre-pregnancy obesity is associated with elevated maternal hepcidin, albeit no signs of lowered cord blood iron status were shown. Medical history of hypothyroidism following the restoration of euthyroidism does not substantially influence maternal nor cord blood hepcidin concentration, as well as fetal iron homeostasis, even though free thyroid hormone levels correlate with maternal hepcidin.

Obesity is associated with increased level of kisspeptin in mothers' blood and umbilical cord blood - a pilot study.

OBJECTIVE: Kisspeptin (KP) is a major regulator of reproductive functions. It has also been shown to be involved in the metabolic changes associated with obesity. According to the well-established concept of prenatal programming, environmental factors can influence physiological and behavioral systems at the early stages of development. Thus, we hypothesized that in pregnant women, obesity can be associated with alterations in the levels of KP. We also assumed that the observed changes in obese mothers' blood (MB) would be reflected in the umbilical cord blood (CB). MATERIALS AND METHODS: We collected MB and CB from obese and nonobese women and analyzed the differences in metabolic and hormonal profiles, including KP concentration, using commercially available assays. RESULTS: We found that the level of KP was increased in the MB and CB of obese patients compared to nonobese subjects (p<0.05). A strong correlation was observed between the concentration of KP in MB and CB (r=0.8343; p<0.01). Moreover, we detected that the differences in the adipokine profile observed in the MB were not reflected in CB. CONCLUSIONS: Our results indicate that blood KP concentration can serve as a valuable marker in pregnant women. However, further studies are needed to understand the alterations of this peptide in obese pregnant woman and their potential effects on offspring.

Role of hepcidin in physiology and pathophysiology. Emerging experimental and clinical evidence.

Normal iron metabolism is an inherent feature of maintaining homeostasis. There is a wide range of iron disorders, which arise from iron deficiency or overload. In addition, disturbances in iron metabolism are observed in the course of numerous chronic diseases. Since iron is an essential constituent of hemoglobin, different types of anemia are clinical manifestations of both iron deficit or excess. This seemingly contradictory statement may be elucidated by the presence of hepcidin. Hepcidin is a primary regulator of iron metabolism in the human body. By promoting ferroportin degradation, hepcidin decreases the amount of iron in the circulation due to iron sequestration in the tissues and reduced intestinal absorption. Altered hepcidin concentration is a compensatory mechanism aimed at restoring iron homeostasis in various physiologic states, including pregnancy. However, hepcidin may also participate in the pathophysiologic background of hereditary hemochromatosis, anemia of chronic disease, myelodysplastic syndromes or ß-thalassemia. Moreover, hepcidin is an acute-phase protein involved in innate immunity reactions. In our paper, we provide a comprehensive review of the physiologic and pathophysiologic functions of hepcidin. We present current knowledge on the structure, physiologic role and its expression control, as well as demonstrate the contribution of hepcidin in a state of illness. We also summarize the significance of hepcidin in normal and complicated pregnancy. Emphasizing the alterations in hepcidin upon treatment of specific diseases and their position in certain pathomechanisms, we support clinicians with practical aspects related to hepcidin.

Tenebrio molitor and Zophobas morio full-fat meals as functional feed additives affect broiler chickens' growth performance and immune system traits.

This study was conducted to investigate the effect of insect full-fat meals (Tenebrio molitor and Zophobas morio larvae), added "on top" of a complete diet or calculated into diets, on the growth performance, selected blood, and immune system traits of broiler chickens. 1,000 one-day-old female Ross 308 broiler chicks were used in 2 independent experiments. In the first trial, the birds were randomly assigned to 6 treatments, 10 replicate pens per treatment, and 10 birds per pen, i.e., negative control; positive control with salinomycin addition (60 mg/kg diet), and addition of 0.2% and 0.3% of T. molitor and Z. morio full-fat meals "on top". In the second experiment, 4 treatments, 10 replicate pens per treatment, and 10 birds per pen were set, i.e., negative control, positive control with salinomycin addition (60 mg/kg diet), and 0.3% of T. molitor and Z. morio full-fat meals calculated in the diets. In both trials the supplementation of insects increased the BWG (Exp. 1: P = 0.024; Exp. 2: P = 0.046) and FI (Exp. 1: P = 0.022; Exp. 2: P = 0.026), and no negative effect on the FCR was recorded in experiment one (P = 0.514), however in second trial insects addition increased FCR values (P = 0.011). In addition, in the first trial, groups fed insects and PC comparing to NC decreased the IgY (P = 0.045) and IgM, (P < 0.001) levels. In the second experiment, IgM levels were also decreased (P < 0.001) in groups fed insects comparing to NC. Moreover, in first trial the IgM levels were negatively correlated to the BWG (r = -0.4845) and FI (r = -0.4986), with statistically significant values (P < 0.001). In conclusion, the current results confirmed that small amount addition (0.2% and 0.3%) of T. molitor and Z. morio full-fat meals to the diet of broiler chickens can improve growth performance and change selected the immune system traits.

Replacement of soybean oil by Hermetia illucens fat in turkey nutrition: effect on performance, digestibility, microbial community, immune and physiological status and final product quality.

1. The aim of the present study was to investigate the effect of partial (50%) or total replacement of soybean oil (SO) by black soldier fly larvae (BSFL) fat on the growth performance, coefficients of apparent nutrient digestibility, selected internal organ weights and length, pancreatic enzyme activity and gastrointestinal tract (GIT) microecology modulation, as well as microbiota activity, physiological and immunological responses in young turkey poults. 2. A total of 216, seven day old female turkeys (B.U.T 6) were randomly distributed to three dietary treatments using six replicate pens per group with 12 birds per pen. The following design of the trial was applied: SO 100% soybean oil; BSFL50 a 50/50 combination of SO and BSFL fat; or 100% BSFL fat (total replacement of SO). 3. The use of BSFL fat did not affect the growth performance, nutrient digestibility, GIT morphology, or quality of the breast and thigh muscles. However, reduced trypsin activity was noticed in the BSFL100 group, but this had no effect on digestibility. Total replacement of SO reduced proliferation of potentially pathogenic bacteria, i.e., Enterobacteriaceae spp., as well as decreasing levels of IL-6, while partial substitution lowered the TNF-α concentration. 4. The replacement of commonly used SO by BSFL fat can be successfully applied in young turkey poult nutrition. BSFL fat may be considered an antimicrobial agent and support immune responses.

Simultaneous supplementation with iron and folic acid can affect Slc11a2 and Slc46a1 transcription and metabolite concentrations in rats.

The present study aimed at analysing how dietary folic acid (FA) and Fe deficiency, followed by supplementation with these nutrients, affects the expression of folate and Fe transporters in the duodenum, as well as FA and Fe status. After a deficiency period, Wistar rats were randomised to a group fed with a diet deficient in FA and supplemented with Fe (DFE), a diet deficient in Fe and supplemented with FA, a diet supplemented with Fe and FA (FEFOL), a diet deficient in Fe and FA (D) or a control diet (C). Tissue collection was performed after 2, 10 or 21 d of these diets. Group D had higher Slc11a2 mRNA levels than the DFE group at every time point and there were differences in mRNA levels of Slc46a1 between the DFE and the FEFOL groups at the third time point, but we observed no differences in protein levels between the groups. The DFE and D groups not only had lower serum folate concentrations at every time point but also had the highest homocysteine concentrations. Total Fe binding capacity concentrations were the lowest in the DFE group at the first time point and in the DFE and the FEFOL groups at the final time point. Simultaneous supplementation with FA and Fe resulted in significantly higher Hb concentrations than did supplementation with these nutrients alone. Our findings indicate that dietary FA and Fe deficiency, and subsequent supplementation with these nutrients, affects transcription but not the protein levels of FA and Fe transporters in the duodenum.

Effect of ostarine (enobosarm/GTX024), a selective androgen receptor modulator, on adipocyte metabolism in Wistar rats.

Synthetic ligands of androgen receptor (AR) are a standard in the treatment of androgen deficiency. One of the effects of androgen deficiency is the disturbance in the homeostasis of lipid metabolism. Till date, there are no effective compounds developed to treat androgen deficiency without having any side effects. Nonsteroidal selective androgen receptor modulators (SARMs) are a promising solution for various clinical indications. In this study, we investigated the effect of ostarine (enobosarm), a nonsteroidal SARM, on the rat adipocyte metabolism using in vitro techniques. Isolated rat adipocytes were incubated in the presence of different concentrations of ostarine. Control incubation with testosterone as the natural ligand for AR was performed. AR inhibitors were used to investigate the genomic activity of ostarine. Changes in the intensity of lipolysis, lipogenesis, and the secretion of leptin and adiponectin were measured. Moreover, the gene expression of leptin and adiponectin was assessed. For the first time, we have shown that ostarine has a significant effect on the intensity of lipid metabolism. Ostarine downregulates the expression of leptin and adiponectin mRNAs, as well as decreases their release from rat adipocytes. According to our results, ostarine acts via AR with a similar effect as testosterone in the regulation of lipid metabolism and endocrine function of mature rat adipocytes in vitro. Our results indicate the need for further studies on the effects of SARM on the whole organism.

Regular cold water swimming during winter time affects resting hematological parameters and serum erythropoietin.

Recreational winter swimming in cold sea water evokes body responses to regularly repeated cold water immersion. However, the understanding of adaptive changes is still limited and data regarding very short-term exposure to severe cold stress are scarce. The purpose of the study was to examine the effects of regular active cold water exposure on resting blood elements and erythropoietin in male and female cold water swimmers (CWSs). Thirty four healthy subjects (18 men and 16 women) aged 50.0 ± 12.2 years were swimming in cold sea water during winter season at least twice a week. The average water temperature was 9.5°C in October, 1.0°C in January and 4.4°C at the end of April. Fasting blood samples were taken within the first weeks of October, January and April. Serum erythropoietin (EPO), complete blood count (CBC) including evaluation of: red blood cells (RBC count, hemoglobin, hematocrit and RBC indices), white blood cells (WBC count with WBC differential), platelets (PLT count), serum folate and serum immunoglobulins (IgG, IgA, IgM) were determined. Between October and April an increase was observed in the following parameters: RBC (from 4.8 x 1012/L to 5.2 x 1012/L, P < 0.001), hemoglobin (from 8.6 mmol/L to 9.4 mmol/L, P < 0.001), MCH (from 1.8 fmol to 1.9 fmol, P = 0.003), MCHC (from 19.9 mmol/L to 20.6 mmol/L, P < 0.001), EPO (from 6.3 IU/L to 8.1 IU/L, P = 0.001). At the same time decreased concentrations of PLT (from 249.9 x 109/L to 221.6 x 109/L, P = 0.005), folate (from 10.5 ng/mL to 7.4 ng/mL, P < 0.001) and immunoglobulins (IgG: from 11.8 g/L to 10.9 g/L, P < 0.001; IgA: from 2.5 g/L to 2.2 g/L, P < 0.001; IgM: from 0.9 g/L to 0.8 g/L, P < 0.001). Statistically significant changes in EPO and PLT values were noted only in female CWSs. We conclude that regular cold water swimming induces adaptive changes in the resting blood elements and EPO concentrations which are more evident in female organism.

Orexin A but not orexin B regulates lipid metabolism and leptin secretion in isolated porcine adipocytes.

It is well known that orexins are involved in the metabolism and endocrine function of rodent adipocytes, but there are no data on other animal species, including pigs. Therefore, in this study, we tested the hypothesis that orexin A (OxA) and orexin B (OxB) modulate the metabolism and endocrine functions of isolated porcine adipocytes and adipose tissue explants. Moreover, we characterized the possible mechanism of OxA action in porcine adipocytes. According to the results, both orexin receptor 1 and orexin receptor 2 were expressed in the porcine adipose tissue. We found that OxA suppressed the release of glycerol from porcine adipocytes both in the absence (basal lipolysis; P < 0.05) and in the presence (stimulated lipolysis; P < 0.05) of isoproterenol. Orexin A increased basal and insulin-stimulated glucose uptake (P < 0.05), as well as it enhanced the rate of glucose incorporation into lipids with insulin (stimulated lipogenesis; P < 0.01) or without insulin (basal; P < 0.05). We have also shown that OxA stimulated the mRNA expression of glucose transporter 4 (P < 0.05) and its translocation into the plasma membrane (P < 0.01). Moreover, OxA upregulated the mRNA expression of leptin in isolated porcine adipocytes (P < 0.05) and increased the secretion of leptin (P < 0.05). We have also demonstrated one of the possible mechanisms of OxA action in adipocytes. In the presence of extracellular-signal-regulated kinase 1 and 2 (ERK1/2) inhibitor, the effect of OxA was not detectable in porcine adipocytes, which indicates that this peptide increased cell viability via ERK1/2 pathway (P < 0.05). However, OxB did not show any effect on the metabolism and endocrine functions of porcine adipocytes. In summary, we have shown for the first time that OxA has a significant impact on the intensity of lipolysis, glucose uptake, lipogenesis, as well as on the expression and secretion of leptin. Therefore, we conclude that OxA but not OxB regulates lipid metabolism in porcine adipose tissue and that this regulation is partly mediated via ERK1/2 pathway. The action of orexins should be further explored to better understand their role in the regulation of adiposity in pigs.

Serum levels of spexin and kisspeptin negatively correlate with obesity and insulin resistance in women.

Spexin (SPX) and kisspeptin (KISS) are novel peptides relevant in the context of regulation of metabolism, food intake, puberty and reproduction. Here, we studied changes of serum SPX and KISS levels in female non-obese volunteers (BMI<25 kg/m(2)) and obese patients (BMI>35 kg/m(2)). Correlations between SPX or KISS with BMI, McAuley index, QUICKI, HOMA IR, serum levels of insulin, glucagon, leptin, adiponectin, orexin-A, obestatin, ghrelin and GLP-1 were assessed. Obese patients had lower SPX and KISS levels as compared to non-obese volunteers (SPX: 4.48+/-0.19 ng/ml vs. 6.63+/-0.29 ng/ml; p<0.001, KISS: 1.357+/-0.15 nmol/l vs. 2.165+/-0.174 nmol/l; p<0.01). SPX negatively correlated with BMI, HOMA-IR, insulin, glucagon, active ghrelin and leptin. Positive correlations were found between SPX and QUICKI index, McAuley index, serum levels of obestatin, GLP-1 and adiponectin and orexin-A Serum KISS negatively correlated with BMI, HOMA-IR, serum levels of insulin, glucagon, active ghrelin and leptin. KISS positively correlated with QUICKI index, McAuley index and adiponectin. In summary, SPX and KISS show negative correlations with obesity, insulin resistance indices, and hormones known to affect insulin sensitivity in females. Both, SPX and KISS could be therefore relevant in the pathophysiology of obesity and insulin resistance.

The physiological response of broiler chickens to the dietary supplementation of the bacteriocin nisin and ionophore coccidiostats.

The aim of this study was to investigate the effect of dietary supplementation with nisin alone or in combination with salinomycin or monensin on broiler chickens in terms of growth performance, selected blood parameters, digestive enzyme activity, apparent nutrient digestibility, and tibiotarsus mineralization, as well as selected gastrointestinal tract (GIT) organ weights, intestinal length, and central immune organ weights. Two independent experiments, each including 400 one-day-old female Ross 308 chicks differing in ionophore coccidiostats, i.e., salinomycin and monensin supplementation, were conducted. The following treatments were applied: experiment 1: NA-no additives, SAL-salinomycin (60 mg/kg diet), NIS-nisin (2,700 IU/kg diet), SAL+NIS-salinomycin (60 mg/kg diet) and nisin (2,700 IU/kg diet); experiment 2: NA-no additives, MON-monensin (100 mg/kg diet), NIS-nisin (2,700 IU/kg diet) and MON+NIS-monensin (100 mg/kg diet) and nisin (2,700 IU/kg diet). The addition of nisin with or without ionophores to the birds' diet improved broiler growth performance in terms of BWG and FCR (days 1 to 14) and BWG and FI (15 to 35 d; 1 to 35 d). Salinomycin showed effects similar to those of nisin influence on growth performance (1 to 35 d), while monensin supplementation resulted in lower BWG. Moreover, no additive effect between nisin and ionophores was observed. Nisin and salinomycin had no influence on the serum concentration of selected hormones and other blood biochemical parameters except glucose, which was reduced by nisin. A decrease in lipase activity was observed during nisin and salinomycin supplementation, while the apparent ileal digestibility of fat was not affected. However, the digestibility of crude protein increased with nisin administration. Additionally, the effects of nisin on decreasing the weight and length of GIT segments were observed. Supplementation with nisin and monensin was not associated with a negative impact on tibiotarsus mineralization and the immune organ index. This study suggests that nisin may be used in broiler nutrition as a growth promotor, with no negative influence on the bird's metabolism or immune status.

Effects of Orchidectomy and Testosterone Replacement on Numbers of Kisspeptin-, Neurokinin B-, and Dynorphin A-Immunoreactive Neurones in the Arcuate Nucleus of the Hypothalamus in Obese and Diabetic Rats.

Neurones expressing kisspeptin, neurokinin B and dynorphin A, located in the arcuate nucleus of the hypothalamus (ARC), are important regulators of reproduction. Their functions depend on metabolic and hormonal status. We hypothesised that male rats with high-fat diet-induced obesity (DIO) and/or streptozotocin-induced diabetes mellitus type 1 (DM1) and type 2 (DM2) will have alterations in numbers of immunoreactive (-IR) cells: kisspeptin-IR and/or neurokinin B-IR and dynorphin A-IR neurones in the ARC in the sham condition. In addition, orchidectomy alone (ORX) and with testosterone treatment (ORX+T) will unmask possible deficits in the response of these neurones in DIO, and/or DM1 and DM2 rats. Rats were assigned to four groups: a control (C) and one diabetic group (DM1) were fed a regular chow diet, whereas the obese group (DIO) and the other diabetic group (DM2) were fed a high-fat diet. To induce diabetes, streptozotocin was injected. After 6 weeks, each group was divided into three subgroups: ORX, ORX+T and sham. After another 2 weeks, metabolic and hormonal profiles were assessed and immunocytochemistry was performed. We found that: (1) under sham conditions: (i) DM1 and DM2 animals had higher numbers of kisspeptin-IR cells than controls and (ii) DM2 rats had increased numbers of neurokinin B-IR and dynorphin A-IR cells compared to C animals; (2) ORX and ORX+T treatments unmasked deficits of the studied neurones in DM1 and DM2 but not in DIO animals; and (3) DIO, DM1 and DM2 rats had altered metabolic and hormonal profiles, in particular decreased levels of testosterone. We concluded that alterations in numbers of kisspeptin-IR and neurokinin B-IR neurones in the ARC and their response to ORX and ORX+T may account for disruptions of metabolic and reproductive functions in diabetic but not in obese rats.

Chronic orexin-A (hypocretin-1) treatment of type 2 diabetic rats improves glucose control and beta-cell functions.

Orexin regulates food intake and energy expenditure. Here, we test the ability of orexin-A (OXA, hypocretin-1) at improving metabolic control in type 2 diabetic animals and elaborate potential mechanisms of action. Rats with experimentally induced type 2 diabetes by a combination of streptozotocin injection and high-fat diet feeding were chronically infused with OXA. In vitro experiments were conducted on isolated pancreatic islets, primary adipocytes and insulin secreting INS-1E cells. OXA improved glucose control, enhanced insulin sensitivity and attenuated pancreatic ß-cell loss in type 2 diabetic rats. Ex vivo, apoptotic death of pancreatic islets isolated from OXA-treated type 2 diabetic animals as well as the impairment of glucose-stimulated insulin secretion were attenuated, as compared to islets derived from vehicle-treated rats. OXA reduced plasma tumor necrosis factor-α (TNF-α) and non-esterified fatty acids (NEFA) levels in type 2 diabetic rats. OXA decreased palmitate- and TNF-α-induced apoptosis of INS-1E cells. OXA improves glucose control by enhancing insulin sensitivity and protecting ß-cells from apoptotic cell death in type 2 diabetic animals.

Effects of high-fat diet-induced obesity and diabetes on Kiss1 and GPR54 expression in the hypothalamic-pituitary-gonadal (HPG) axis and peripheral organs (fat, pancreas and liver) in male rats.

Recent data indicates that kisspeptin, encoded by the KISS1 gene, could play a role in transducing metabolic information into the hypothalamic-pituitary-gonadal (HPG) axis, the mechanism that controls reproductive functions. Numerous studies have shown that in a state of negative energy balance, the hypothalamic kisspeptin system is impaired. However, data concerning positive energy balance (e.g. diabetes and obesity) and the role of kisspeptin in the peripheral tissues is scant. We hypothesized that: 1) in diet-induced obese (DIO) male rats and/or rats with diabetes type 1 (DM1) and type 2 (DM2), altered reproductive functions are related to an imbalance in Kiss1 and GPR54 mRNA in the HPG axis; and 2) in DIO and/or DM1 and/or DM2 rats, Kiss1 and GPR 54 expression are altered in the peripheral tissues involved in metabolic functions (fat, pancreas and liver). Animals were fed a high-fat or control diets and STZ (streptozotocin - toxin, which destroys the pancreas) was injected in high or low doses to induce diabetes type 1 (DM1) or diabetes type 2 (DM2), respectively. RT-PCR and Western blot techniques were used to assess the expression of Kiss1 and GRP54 in tissues. At the level of mRNA, we found that diabetic but not obese rats have alterations in Kiss1 and/or GPR54 mRNA levels in the HPG axis as well as in peripheral tissues involved in metabolic functions (fat, pancreas and liver). The most severe changes were seen in DM1 rats. However, in the case of protein levels in the peripheral tissues (fat, pancreas and liver), changes in Kiss1/GPR54 expression were noticed in DIO, DM1 and DM2 animals and were tissue-specific. Our data support the hypothesis that alterations in Kiss1/GPR54 balance may account for both reproductive and metabolic abnormalities reported in obese and diabetic rats.

TRPV6 channel modulates proliferation of insulin secreting INS-1E beta cell line.

Transient receptor potential channel vanilloid type 6 (TRPV6) is a non-selective cation channel with high permeability for Ca²âº ions. So far, the role of TRPV6 in pancreatic beta cells is unknown. In the present study, we characterized the role of TRPV6 in controlling calcium signaling, cell proliferation as well as insulin expression, and secretion in experimental INS-1E beta cell model. TRPV6 protein production was downregulated using siRNA by approx. 70%, as detected by Western blot. Intracellular free Ca²âº ([Ca²âº]i) was measured by fluorescence Ca²âº imaging using fura-2. Calcineurin/NFAT signaling was analyzed using a NFAT reporter assay as well as a calcineurin activity assay. TRPV6 downregulation resulted in impaired cellular calcium influx. Its downregulation also reduced cell proliferation and decreased insulin mRNA expression. These changes were companied by the inhibition of the calcineurin/NFAT signaling. In contrast, insulin exocytosis was not affected by TRPV6 downregulation. In conclusion, this study demonstrates for the first time the expression of TRPV6 in INS-1E cells and rat pancreatic beta cells and describes its role in modulating calcium signaling, beta cell proliferation and insulin mRNA expression. In contrast, TRPV6 fails to influence insulin secretion.

In ovo injection of prebiotics and synbiotics affects the digestive potency of the pancreas in growing chickens.

The purpose of the study was to examine the effect of 2 prebiotics and 2 synbiotics on the digestive potency of pancreas in 1-, 3-, 7-, 14-, 21-, and 34-day-old cockerels. Prebiotics (inulin and Bi²tos) and synbiotics (inulin + Lactococcus lactis subsp. lactis and Bi²tos + Lactococcus lactis subsp. cremoris) were injected in ovo into the air cell on the 12th d embryonic development. Their application increased the activity of amylase, lipase, and trypsin in the pancreas. The most pronounced changes were observed at the end of the investigated rearing period (d 34). The strongest stimulative effects on amylase were shown by both synbiotics, on lipase synbiotic Bi²tos + Lactococcus lactis subsp. cremoris, and on trypsin all the used prebiotics and synbiotics. Simultaneously, neither the absolute nor the relative mass of the pancreas in comparison to control group were changed. Also, the injected in ovo compounds did not cause a deterioration in the posthatching condition of the chicken liver, as determined by measurement of the activity of marker enzymes in the blood (alanine aminotransferase and aspartate aminotransferase). Treatment with the prebiotics and synbiotics did not change the feed conversion ratio but Bi²tos (galacto-oligosaccharide) and inulin (fructan) + Lactococcus lactis subsp. lactis significantly increased final BW.

Resistin - from gene expression to development of diabetes.

Adipocyte-originated hormonal factors, playing a role of signaling particles, are widely engaged in energy control, feeding behavior and general glucose or lipid metabolism. One of them – resistin – has been suspected to initiate or develop insulin resistance and diabetes. From the moment of discovery of resistin, during last 13 years, numerous investigations put some light on a potential role of this hormone in mammals. In this review knowledge on resistin, including its structure, physiological role related to obesity and diabetes, as well as, gene sequence and phenotypic effects of the identified polymorphisms in human and domestic mammals is discussed.

Obestatin inhibits lipogenesis and glucose uptake in isolated primary rat adipocytes.

Ghrelin and obestatin are encoded by the preproghrelin gene and originate from post-translational processing of the preproghrelin peptide. Obestatin is mainly present in the stomach, but its action is focused on appetite inhibition in opposition to ghrelin function. Recently, it has been presented that obestatin may regulate adipocyte metabolism and influence fat content. However, obestatin action is still poorly understood. Therefore, we aimed to investigate obestatin function on adipocyte metabolism in the rat. We studied changes in the mRNA expression of active and inactive isoforms of obestatin receptors. In addition, we analyzed influence of obestatin on lipogenesis, lipolysis and glucose transport in isolated adipocytes. Moreover, we also performed analysis of obestatin action on lipolysis in differentiated rat preadipocytes with silenced obestatin receptor. We found significantly higher expression of the obestatin receptor Gpr39-1a active form at an mRNA level following adipocytes incubation with obestatin. We did not observe expression changes in the inactive form of obestatin receptor Gpr39-1b. Additionally, we found significant changes in Gpr39-1a expression following obestatin receptor silencing in cells incubated with obestatin in comparison to control. Obestatin inhibited both, basal and insulin-stimulated lipogenesis and glucose transport in adipocytes. Furthermore, obestatin potentiated adrenalin-stimulated lipolysis. We also found reduced glycerol release following obestatin incubation in adipocytes with silenced Gpr39 gene. Our results indicate that obestatin acts via the GPR39 receptor in isolated adipocytes, and that through this mechanism obestatin influences lipid accumulation, glucose uptake and lipolysis.