Combined spectroscopic, biochemical and chemometric approach toward finding of biochemical markers of obesity.

BACKGROUND: Early-stage detection of subclinical obesity-driven systemic changes is a challenging area of medical diagnostics, where the most popular existing measures - such as body mass index - BMI - often fall short of providing a realistic estimate of adiposity and, therefore, of ongoing pathologies at the systemic, tissue and cellular level. In the quest for identifying new more robust diagnostic markers, whole-organ analysis of chemical elements is a promising approach for identifying candidate proxies of obesity status in the system. METHODS: Total Reflection X-ray fluorescence (TXRF) coupled with biochemical assays, chemometrics and statistical validation was used as a new integrated pipeline for marker identification in external ear samples of obese animals. The specimens were taken from obese animals fed a high calorie diet as well as from lean intact animals fed a standard diet. RESULTS: The most significant differences in the content of K, Fe, Br, and Rb between the studied groups of the animals were identified. However, with the methodology applied Rb was found the most robust biochemical discriminator of early-stage obesity effects, as validated by the logistic regression model. We observed no relationship between the levels of the elements consumed by the animals and their apparent content in the earlobe tissue samples. CONCLUSIONS: Our preliminary study confirms that obesity alters tissue trace metal metabolism and shows the proposed new approach as an accurate and reliable methodology for detecting tissue elemental obesity-related alterations. GENERAL SIGNIFICANCE: This result can be of practical significance for designing new point-of-care systems for obesity screening tests, taking advantage of direct/indirect Rb measurements.

The New Markers of Early Obesity-Related Organ and Metabolic Abnormalities.

The objective of our study was to identify new markers related to excessive body adiposity and its early consequences. For this purpose we determined serum FGF-19 and FGF-21 concentrations in obese rats, whose role in the pathogenesis of obesity is not yet established. In addition, a total reflection X-ray fluorescence technique was applied to determine the elemental chemistry of certain tissues affected by obesity. Next, the new biochemical and molecular parameters were correlated with well-known obesity-related markers of metabolic abnormalities. Our obese rats were characterized by increased calorie consumption and body adiposity, hypercholesterolemia, elevated levels of liver enzymes and FGF-21, while the level of FGF-19 was reduced. Strong relationships between new hormones and established metabolic parameters were observed. Furthermore, we demonstrated that obesity had the greatest effect on elemental composition in the adipose tissue and liver and that rubidium (Rb) had the highest importance in distinguishing the studied groups of animals. Tissue Rb strongly correlated with both well-known and new markers of obesity. In conclusion, we confirmed serum FGF-19 and FGF-21 as useful new markers of obesity-related metabolic alternations and we robustly propose Rb as a novel indicator of excessive body adiposity and its early consequences. However, further investigations are encouraged to address this clinical issue.

Determining the amount of potentially bioavailable phenolic compounds and bioelements in edible mushroom mycelia of Agaricus bisporus, Cantharellus cibarius, and Lentinula edodes.

Release of bioelements and phenolic compounds from edible mushrooms (Agaricus bisporus, Cantharellus cibarius, and Lentinula edodes) enriched with zinc, selenium, l-phenylalanine, alone and as a mixture was examined using a simulated human gastrointestinal digestion method. Due to the extensive amount of data obtained, in order to interpret them more precisely in the work, the methods of chemometric analysis (Cluster Analysis-CA and Principal Compenent Analysis-PCA) were additionally applied. The results showed mycelium of L. edodes has the best health-promoting properties and addition of mixture to the media increased significantly the synthesis of p-hydroxybenzoic and protocatechuic acid (267 and 16.3 mg/100 g d.w.). After extraction into artificial digestive juices, 97.4 mg/100 g d.w. p-hydroxybenzoic acid and 15.6 mg/100 g d.w. of protocatechuic acid were released. The greatest amounts of Se and Zn were extracted from enriched A. bisporus mycelium (32.3 and 342 mg/100 g d.w., respectively). This study confirmed that mycelium might prevent nutritional deficiencies in the diet through use of functional foods.

Comparison of Elemental Anomalies Following Implantation of Different Cell Lines of Glioblastoma Multiforme in the Rat Brain: A Total Reflection X-ray Fluorescence Spectroscopy Study.

Glioblastoma multiforme (GBM) is a primary brain tumor with a very high degree of malignancy and is classified by WHO as a glioma IV. At present, the treatment of patients suffering from GBM is based on surgical resection of the tumor with maximal protection of surrounding tissues followed by radio- and pharmacological therapy using temozolomide as the most frequently recommended drug. This strategy, however, does not guarantee success and has devastating consequences. Testing of new substances or therapies having potential in the treatment of GBM as well as detection of their side effects cannot be done on humans. Animal models of the disease are usually used for these purposes, and one possibility is the implantation of human tumor cells into rodent brains. Such a solution was used in the present study the purpose of which was comparison of elemental anomalies appearing in the brain as a result of implantation of different glioblastoma cell lines. These were two commercially available cell lines (U87MG and T98G), as well as tumor cells taken directly from a patient diagnosed with GBM. Using total reflection X-ray fluorescence we determined the contents of P, S, K, Ca, Fe, Cu, Zn, and Se in implanted-left and intact-right brain hemispheres. The number of elemental anomalies registered for both hemispheres was positively correlated with the invasiveness of GBM cells and was the highest for animals subjected to U87MG cell implantation, which presented significant decrease of P, K, and Cu levels and an increase of Se concentration within the left hemisphere. The abnormality common for all three groups of animals subjected to glioma cell implantation was increased Fe level in the brain, which may result from higher blood supply or the presence of hemorrhaging regions. In the case of the intact hemisphere, elevated Fe concentration may also indicate higher neuronal activity caused by taking over some functions of the left hemisphere impaired as a result of tumor growth.

Comparison of ultrasmall IONPs and Fe salts biocompatibility and activity in multi-cellular in vitro models.

In the paper, the results of the first regular studies of ultra-small iron oxide nanoparticles (IONPs) toxicity in vitro were presented. The influence of PEG-coated NPs with 5 nm magnetite core on six different cell lines was examined. These were: human bronchial fibroblasts, human embryonic kidney cells (HEK293T), two glioblastoma multiforme (GBM) cell lines as well as GBM cells isolated from a brain tumor of patient. Additionally, mouse macrophages were included in the study. The influence of IONPs in three different doses (1, 5 and 25 µg Fe/ml) on the viability, proliferation and migration activity of cells was assessed. Moreover, quantifying the intracellular ROS production, we determined the level of oxidative stress in cells exposed to IONPs. In the paper, for the first time, the effect of Fe in the form of IONPs was compared with the analogical data obtained for iron salts solutions containing the same amount of Fe, on the similar oxidation state. Our results clearly showed that the influence of iron on the living cells strongly depends not only on the used cell line, dose and exposure time but also on the form in which this element was administered to the culture. Notably, nanoparticles can stimulate the proliferation of some cell lines, including glioblastoma multiforme. Compared to Fe salts, they have a stronger negative impact on the viability of the cells tested. Ultra-small NPs, also, more often positively affect cell motility which seem to differ them from the NPs with larger core diameters.

Selected edible medicinal mushrooms from Pleurotus genus as an answer for human civilization diseases.

Edible mushrooms are classified as a functional food. The study aimed to initiate in vitro cultures of selected species of Pleurotus: P. citrinopileatus, P. djamor, P. eryngii, P. florida, P. ostreatus, and P. pulmonarius and to optimize the method of cultivation of these species to obtain raw materials characterized by pro-health properties. Another objective was to analyze the biologically active substances in the obtained mushroom materials. By determining the organic compounds and bioelements present in the species selected for the study, it was found that the fruiting bodies obtained by cultivation were characterized by a high content of phenolic and indole compounds. Similarly, the mycelia obtained from in vitro culture were found to contain significant amounts of organic compounds exhibiting biological effects such as lovastatin. The study revealed that the composition of biologically active substances varied between the mycelia obtained from in vitro cultures and the fruiting bodies obtained by cultivation.

The use of Callitriche cophocarpa Sendtn. for the reclamation of Cr-contaminated freshwater habitat: benefits and limitations.

This work is the first attempt to evaluate suitability of Callitriche cophocarpa Sendtn. (water-starwort) to remove Cr under real-world conditions. Our earlier laboratory-scale studies demonstrated outstanding hyperaccumulation properties of this aquatic higher plant (macrophyte) toward chromium in solution. We introduced C. cophocarpa plants into the watershed with sediments heavily polluted (on average 1400 mg/kg d.w. of Cr) by a tannery. The plants grew vigorously and exhibited no physiological or anatomical disorders. Based on chemical fractionations of bottom sediments, we found low Cr bioavailability. The element was strongly associated with the sediments and could be classified into the following fractions (%): oxidizable III (68.2) > residual IV (28.8) > reducible II (1.6) > exchangeable I (1.4). Despite this, Cr content in plant organs at the contaminated sites was 33 up to 83 times greater than in the control leaf/stem and roots, respectively. Altering redox potential during, i.e., sediment deposition on land may change chemical forms of bound metals in a solid phase, and thus further increase Cr phytoextraction by plants. With this in mind, we concluded that the species, being an outstanding Cr accumulator under laboratory conditions, can be useful in the reclamation of Cr-polluted sediments under controlled, oxidizing conditions.

Lentinula edodes as a Source of Bioelements Released into Artificial Digestive Juices and Potential Anti-inflammatory Material.

Lentinula edodes (shiitake), an edible and medicinal mushroom, was chosen for this study with the aim of evaluating the possibility of release of bioelements into artificial digestive juices and analyzing the anti-inflammatory properties. The extracts were prepared from fruiting bodies and biomass enriched with copper (Cu), zinc (Zn), and selenium (Se). The content of bioelements was analyzed by total reflection X-ray fluorescence method. Relatively low content of elements was observed in the fruiting bodies: Cu-1.6, Zn-7.6, and Se-0.12 mg/100 g d.w. compared to mycelial cultures. The anti-inflammatory properties were evaluated in RAW 264.7 cells. Based on the levels of cyclooxygenase 2 protein, nuclear factor erythroid 2-related factor 2, and peroxisome proliferator-activated receptor γ determined using Western blot technique, it was found that the addition of bioelements enhanced the anti-inflammatory properties of mycelium. This indicates that L. edodes cultured on a suitable medium may be used as a potential component of anti-inflammatory products.

Correction to: Lentinula edodes as a Source of Bioelements Released Into Artificial Digestive Juices and Potential Anti-inflammatory Material.

The original version of this article unfortunately contained a mistake.

Selected metal content and antioxidant capacity of Sambucus nigra flowers from the urban areas versus soil parameters and traffic intensity.

The metal accumulation and antioxidant contents in flowers of wild specimens of European elder (Sambucus nigra L.), a famous medicinal plant and valuable component in the urban landscape, were determined. The total reflection X-ray fluorescence revealed the presence of K, Rb, Ca, Sr, Cr, Mn, Fe, Cu, and Zn associated with flowers. A typical, large, non-industrial city with considerable traffic and atmospheric pollution resulting from smog was chosen as a place of sampling. Obtained results were correlated with selected parameters of soil and the intensity of surrounding traffic. The flowers were relatively rich in elements K, Ca, Cu, Rb, and antioxidants, while it did not accumulate heavy metals potentially bioavailable in the soil. The correlation between street traffic and the content of Fe, Cr, and Zn in elderflowers was revealed; the metal quantities were below levels harmful to humans. Flowers from the city center exhibited higher antioxidant and radical scavenging capacities comparing to plants from the areas of little traffic. The antioxidant parameters were negatively correlated with the silty fraction content and positively with the potentially bioavailable levels of Ti and Mn in soils and increased with the amount of Rb in the flowers. It was proven for the first time that the urban specimens of wild S. nigra can perform as a local source of beneficial flowers providing cost-effective support in disease prevention and treatment.

Long-lasting antidepressant-like activity of the GPR39 zinc receptor agonist TC-G 1008.

BACKGROUND: The discovery of the zinc-sensing receptor, has provided new possibilities for explaining the neurobiology of zinc. Recent studies indicate that the GPR39 zinc receptor may play an important role in the pathogenesis of depression as well as in the antidepressant mechanism of action. METHODS: In this study we evaluated the time-course of the antidepressant response of the GPR39 agonist (TC-G 1008), imipramine, ZnCl2 and MK-801 in the forced swim test in mice 30 min, 3 h, 6 h and 24 h after acute drug administration as well as after 14-day treatment. Zinc level was measured in serum of mice. BDNF protein level was evaluated in hippocampus following both acute and chronic TC-G 1008 treatment. RESULTS: A single administration of the GPR39 agonist caused an antidepressant-like effect lasting up to 24 h following the injection, which is longer than the effect of imipramine, ZnCl2 and MK-801. Chronic treatment with these compounds caused a decrease in immobility time in the FST. Serum zinc concentrations showed an increased level following chronic ZnCl2 administration, but not following administration of TC-G 1008, imipramine or MK-801. We also observed some tendencies for increased BDNF following acute TC-G 1008 treatment. LIMITATIONS: TC-G 1008 is new drug designed to study GPR39 therefore additional pharmacodynamic and pharmacokinetic properties in preclinical studies are required. CONCLUSION: This study shows for the first time the long-lasting antidepressant effect of the GPR39 agonist in comparison with imipramine, ZnCl2 and MK-801. Our findings suggest that GPR39 should be considered as a target in efforts to develop new antidepressant drugs.

Combined micro-XRF and TXRF methodology for quantitative elemental imaging of tissue samples.

Local differences in structural properties of biological specimens pose a major limitation to quantitative X-ray fluorescence imaging. This is because both the various tissue compartments of different density and variation in the sample thickness upon frequently used freeze-drying come up with the different values of the sample mass per unit area to be taken into account. Even though several solutions to tackle this problem based on the home-made standards for quantification in terms of thickness- and density-independent elemental mass fractions have been proposed, this issue is not addressed enough due to the samples' heterogeneity. In our recent study, we propose a calculation scheme based on combined external-standard micro X-ray fluorescence (micro-XRF) imaging and internal-standard total reflection X-ray fluorescence (TXRF) analysis to determine the corrected elemental mass fraction distributions in commonly analysed rat tissues: kidney, liver and spleen. The results of TXRF analysis of digested large tissue sections together with the mean values of elemental masses per unit area obtained with micro-XRF were employed to determine the average masses per unit area of the samples. The correction for variation of the tissue thickness and density was done through with the use of Compton intensities. Importantly, by its versatility, our novel approach can be used to produce elemental contrast in a variety of biological specimens where local variations in either the sample density or thickness are no longer the issue.

Alterations of Bio-elements, Oxidative, and Inflammatory Status in the Zinc Deficiency Model in Rats.

Our previous study showed that dietary zinc restriction induces depression-like behavior with concomitant up-regulation of the N-methyl-D-aspartate receptor (NMDAR). Because metal ions, oxidative stress, and inflammation are involved in depression/NMDAR function, in the present study, bio-elements (zinc, copper, iron, magnesium, and calcium), oxidative (thiobarbituric acid-reactive substances; protein carbonyl content), and inflammatory (IL-1α, IL-1ß) factors were measured in serum, hippocampus (Hp), and prefrontal cortex (PFC) of male Sprague-Dawley rats subjected to a zinc-adequate (ZnA) (50 mg Zn/kg) or a zinc-deficient (ZnD) (3 mg Zn/kg) diet for 4 or 6 weeks. Both periods of dietary zinc restriction reduced serum zinc and increased serum iron levels. At 4 weeks, lowered zinc level in the PFC and Hp as well as lowered iron level in the PFC of the ZnD rats was observed. At 6 weeks, however, iron level was increased in the PFC of these rats. Although at 6 weeks zinc level in the PFC did not differ between the ZnA and ZnD rats, extracellular zinc concentration after 100 mM KCl stimulation was reduced in the PFC of the ZnD rats and was accompanied by increased extracellular iron and glutamate levels (as measured by the in vivo microdialysis). The examined oxidative and inflammatory parameters were generally enhanced in the tissue of the ZnD animals. The obtained data suggest dynamic redistribution of bio-elements and enhancement of oxidative/inflammatory parameters after dietary zinc restriction, which may have a link with depression-like behavior/NMDAR function/neurodegeneration.

Antidepressant activity of fluoxetine in the zinc deficiency model in rats involves the NMDA receptor complex.

The zinc deficiency animal model of depression has been proposed; however, it has not been validated in a detailed manner. We have recently shown that depression-like behavior induced by dietary zinc restriction is associated with up-regulation of hippocampal N-methyl-d-aspartate receptor (NMDAR). Here we examined the effects of chronic administration of a selective serotonin reuptake inhibitor, fluoxetine (FLX), on behavioral and biochemical alterations (within NMDAR signaling pathway) induced by zinc deficiency. Male Sprague Dawley rats were fed a zinc adequate diet (ZnA, 50mg Zn/kg) or a zinc deficient diet (ZnD, 3mg Zn/kg) for 4 weeks. Then, FLX treatment (10mg/kg, i.p.) begun. Following 2 weeks of FLX administration the behavior of the rats was examined in the forced swim test (FST) and the spontaneous locomotor activity test. Twenty four hours later tissue was harvested. The proteins of NMDAR (GluN1, GluN2A and GluN2B) or AMPAR (GluA1) subunits, p-CREB and BDNF in the hippocampus (Western blot) and serum zinc level (TXRF) were examined. Depression-like behavior induced by ZnD in the FST was sensitive to chronic treatment with FLX. ZnD increased levels of GluN1, GluN2A, GluN2B and decreased pS485-GluA1, p-CREB and BDNF proteins. Administration of FLX counteracted the zinc restriction-induced changes in serum zinc level and hippocampal GluN1, GluN2A, GluN2B and p-CREB but not BDNF or pS845-GluA1 protein levels. This finding adds new evidence to the predictive validity of the proposed zinc deficiency model of depression. Antidepressant-like activity of FLX in the zinc deficiency model is associated with NMDAR complex.

Zinc deficiency in rats is associated with up-regulation of hippocampal NMDA receptor.

RATIONALE: Data indicated that zinc deficiency may contribute to the development of depression; however changes induced by zinc deficiency are not fully described. OBJECTIVES: In the present paper we tested whether the dietary zinc restriction in rats causes alterations in N-methyl-D-aspartate receptor (NMDAR) subunits in brain regions that are relevant to depression. METHODS: Male Sprague Dawley rats were fed a zinc adequate diet (ZnA, 50 mg Zn/kg) or a zinc deficient diet (ZnD, 3 mg Zn/kg) for 4 or 6weeks. Then, the behavior of the rats was examined in the forced swim test, sucrose intake test and social interaction test. Western blot assays were used to study the alterations in NMDAR subunits GluN2A and GluN2B and proteins associated with NMDAR signaling in the hippocampus (Hp) and prefrontal cortex (PFC). RESULTS: Following 4 or 6 weeks of zinc restriction, behavioral despair, anhedonia and a reduction of social behavior occurred in rats with concomitant increased expression of GluN2A and GluN2B and decreased expression of the PSD-95, p-CREB and BDNF protein levels in the Hp. The up-regulation of GluN2A protein was also found in the PFC, but only after prolonged (6 weeks) zinc deprivation. CONCLUSIONS: The procedure of zinc restriction in rats causes behavioral changes that share some similarities to the pathophysiology of depression. Obtained data indicated that depressive-like behavior induced by zinc deficiency is associated with the changes in NMDAR signaling pathway.

GPR39 (zinc receptor) knockout mice exhibit depression-like behavior and CREB/BDNF down-regulation in the hippocampus.

BACKGROUND: Zinc may act as a neurotransmitter in the central nervous system by activation of the GPR39 metabotropic receptors. METHODS: In the present study, we investigated whether GPR39 knockout would cause depressive-like and/or anxiety-like behavior, as measured by the forced swim test, tail suspension test, and light/dark test. We also investigated whether lack of GPR39 would change levels of cAMP response element-binding protein (CREB),brain-derived neurotrophic factor (BDNF) and tropomyosin related kinase B (TrkB) protein in the hippocampus and frontal cortex of GPR39 knockout mice subjected to the forced swim test, as measured by Western-blot analysis. RESULTS: In this study, GPR39 knockout mice showed an increased immobility time in both the forced swim test and tail suspension test, indicating depressive-like behavior and displayed anxiety-like phenotype. GPR39 knockout mice had lower CREB and BDNF levels in the hippocampus, but not in the frontal cortex, which indicates region specificity for the impaired CREB/BDNF pathway (which is important in antidepressant response) in the absence of GPR39. There were no changes in TrkB protein in either structure. In the present study, we also investigated activity in the hypothalamus-pituitary-adrenal axis under both zinc- and GPR39-deficient conditions. Zinc-deficient mice had higher serum corticosterone levels and lower glucocorticoid receptor levels in the hippocampus and frontal cortex. CONCLUSIONS: There were no changes in the GPR39 knockout mice in comparison with the wild-type control mice, which does not support a role of GPR39 in hypothalamus-pituitary-adrenal axis regulation. The results of this study indicate the involvement of the GPR39 Zn(2+)-sensing receptor in the pathophysiology of depression with component of anxiety.

The involvement of the GPR39-Zn(2+)-sensing receptor in the pathophysiology of depression. Studies in rodent models and suicide victims.

Zinc is one of the most important trace elements in our body. Patients suffering from depression show lower serum zinc levels compared to healthy controls. Zincs antagonism to the glutamatergic system seems to be responsible for mood recovery. Recent years have shown that zinc may regulate neurotransmission via the metabotropic GPR39 receptor. Activation of the GPR39-Zn(2+)-sensing receptor (GPR39) triggers diverse neuronal pathways leading to a cAMP-responsive element binding the protein (CREB) expression, which then induces synthesis of the brain-derived neurotrophic factor and, in turn, activation of the Tropomyosin receptor kinase B (TrkB) receptor. In the present study, we investigated the alteration of the GPR39 in different models of depression, such as zinc deficiency and olfactory bulbectomy and in suicide victims. Additionaly, we focused on CREB-BDNF/TrkB under zinc deficient conditions in mice. To demonstrate depressive-like behaviour, a standard and modified forced swim test (FST) was performed. To evaluate expression of GPR39, CREB, BDNF and TrkB, Western Blot analysis was used. Zinc deficient mice and rats showed decreased GPR39 expression in the hippocampus and frontal cortex. A decreased level of hippocampal and cortical GPR39 was also observed in suicide victims. In contrast, increased GPR39 in the hippocampus of olfactory bulbectomized rats was observed. Additionally, we found a decreased expression of CREB, BDNF and TrkB only in the hippocampus of zinc-deficient mice. Our present study demonstrates the associacion of the GPR39 Zn(2+)-sensing receptor in the pathomechanism of depression. Down-regulation of CREB, BDNF, TrkB and GPR39 receptor found under zinc-deficient conditions in the hippocampus, may play an important role in the pathophysiology of mood disorders, since most of patients suffering from depression show lower serum zinc.

Elemental composition of Physarum compressum Alb. et Schw. sporocarps and their structures cultivated on rabbit dung and agar substrates.

The elemental composition of spores, peridium walls, and lime nodes of Physarum compressum sporocarps, cultivated on rabbit dung as a natural growing environment for the slime mold and on artificial agar medium, was compared to evaluate differences that may be dependent on substrates. Whole fruiting bodies and samples of both experimental media were extracted with nitric acid or Parr digest bomb, respectively, and analyzed by means of total X-ray reflection fluorescence (TXRF). Electron probe microanalysis (EPMA) of spores, peridium walls, and lime nodes structure was carried out with the scanning electron microscope equipped with energy-dispersive spectrometer. Because of minute sizes and roughness of investigated structures, Monte Carlo simulations were utilized to establish analytical conditions of EPMA. Biological and geological standards were used in the quantification of element concentrations. According to TXRF, the fruiting bodies from agar medium revealed lower concentrations of K, Ca, Cr, Mn, and Fe in relation to fruiting bodies from the dung, reflecting elemental relationships in the experimental media. According to EPMA, the highest Ca concentration was found in the lime nodes followed by the peridium and the spores. Culturing of the slime molds on the rabbit dung indicated higher concentration of Ca in the lime nodes and peridium walls when compared with those obtained from the sporocarps grown on agar media. The opposite relation was found for the spores. The concentration of Na, Mg, P, S, and Cl was generally lower in all structures of the sporocarps harvested from the dung than from the agar medium. K was in higher concentration in analyzed structures from dung than from agar. Different element uptake (except for Ca and K) was revealed by the two methods: TXRF and EPMA.

Early lifetime zinc supplementation protects zinc-deficient diet-induced alterations.

Preclinical and clinical data indicate the involvement of zinc in the pathophysiology and therapy of depression. A relationship between zinc-deficiency and depression symptoms was recently proposed. The present study investigated alterations in spontaneous locomotor activity and zinc concentrations in the serum, hippocampus and frontal cortex; these alterations were induced by subjecting rats to a zinc-deficient diet, prior subjected after birth to zinc-supplemented diet. Body weight was significantly reduced in animals subjected to the four-week zinc-deficient diet compared to those subjected to the zinc-adequate diet. The two-week zinc-deficient diet induced a significant increase in locomotor activity in all measured time periods (5, 30 and 60 min by 44-62%). The four-week zinc-deficient diet did not affect locomotor activity, while the six-week zinc-deficient diet resulted in a 45% increase in the 5 min time period. Serum zinc concentrations were significantly reduced (by 29%) in animals subjected to the four-week zinc-deficient diet but not in those subjected to the two- or six-week zinc-deficient diets. The zinc-deficient diet did not influence the zinc concentration in the examined brain regions regardless of the length. These results indicate that post-birth supplementation with zinc may protect zinc-deficient diet-induced rapid alterations in zinc homeostasis.