The effect of vitamin E supplementation on brain tissue element levels in epileptic rats.

The aim of this study was to investigate how the application of vitamin E affected the levels of chemical elements in the brain tissues of epilepsy-induced rats. The sample of 40 adult male rats was separated into 4 equal groups: Group 1: control, Group 2: vitamin E; Group 3: penicillin to promote epileptic form activity and Group 4: penicillin + vitamin E. After three months of treatment, an Atomic Absorption Spectrophotometer was used to analyze the presence of the elements in brain tissue sections (brain, brainstem, cerebellum) of the decapitated animals. The levels of magnesium in the groups that received vitamin E (G2 and 4) were significantly higher than in the control group (G1) and the first epilepsy group (G3) (p.05).Chrome and zinc levels in brain, brainstem, and cerebellum tissue of the two epilepsy groups (G3-4) decreased significantly compared to the control group (G1) and the vitamin E group (G2) (p.05). The levels of copper in the brainstem and lead in the cerebellum of the first epilepsy group (G3) were higher than in all other groups (p.05). The findings showed that the application of vitamin E in experimental epilepsy may have a limited effect on element metabolism in brain tissue. A decline in zinc levels in the brain, brainstem and cerebellum tissues in epilepsy groups constitutes another result of our study. This should be examined further to determine whether decreased levels of zinc play a role in epilepsy pathogenesis.

The Effect of 2 Weeks of Naringenin on AQP4, IL-2 and DNA Damage in Brain Ischemia Reperfusion in Rats.

The aim of this study was to determine the effect of different doses of naringenin (NAR) administration for 2 weeks in rats on brain Aquaporin-4 (AQP4), interleukin-2 (IL-2) and 8-Hydroxydeoxyguanosine (8-OhdG) levels in brain ischemia-reperfusion. Experimental groups were formed as follows; 1-Control; 2-Sham Control; 3 Ischemia/ Reperfusion (I/R); 4-Naringenin (Naringenin 50) + I/R; 5-Naringenin (naringenin 100) + I/R. I/R was performed as 1 hour occlusion of the carotid arteries (ischemia) followed by 1 hour reperfusion. Naringenin was supplied for 2 weeks by intraperitoneal. At the end of the experiment, AQP4, IL-2 and 8-OHdG levels were determined in the brain frontal cortex tissue taken from animals killed under anesthesia. AQP4, IL-2 and 8-OHdG levels increased significantly in I/R group. However, both 50 mg/kg and 100 mg/kg two-week administration of naringenin significantly decreased these increased parameters (P 0.001).The results of the study show that intraperitoneal administration of naringenin for two weeks in rats may prevent the damage caused by brain ischemia-reperfusion.

Both experimental hypothyroidism and hyperthyroidism increase cardiac irisin levels in rats.

Irisin is a newly discovered myokine and adipokine that increases total body energy expenditure. The aim of this study was to determine the effect of experimental hypothyroidism and hyperthyroidism on the levels of irisin in heart tissue in rats. The study was performed on the 40 male Sprague-Dawley rats. Experimental groups were designed as; Control, Hypothyroidism, Hypothyroidism+L-Thyroxine, Hyperthyroidism and Hyperthyroidism + PTU. Following 3 weeks experimental period, irisin levels were determined in heart tissues. Hypothyroidism group values of irisin were higher than in the control group, but lower than in the hyperthyroidism group. The hyperthyroidism group had the highest levels of cardiac irisin. The results of the study showed that the experimental hypothyroidism and hyperthyroidism increased the heart irisin levels, but the increase in the hyperthyroidism group was much higher than in the hypothyroidism group. However, treatment of hypothyroidism and hyperthyroidism corrected cardiac irisin levels (Fig. 1, Ref. 28).

3', 4'-dihydroxyflavonol attenuates tissue damage in unilateral testis ischemia-reperfusion in rats.

The purpose of this study was to determine the effect of 3',4'-dihydroxyflavonol (DiOHF) on oxidative damage and antioxidant system in experimental testicular torsion-detorsion.The study included 60 male Wistar albino rats. Study groups were formed as follows: 1. Control; 2. Sham; 3. 720° - 4 hours torsion; 4. 720° - 4 hours torsion + 4 hours detorsion; 5. 720° - 4 hours torsion + DiOHF; 6. 720° - 4 hours torsion + DiOHF + 4 hours detorsion; 7. 720° - 4 hours torsion + 24 hours detorsion; 8. 720° - 4 hours torsion + DiOHF + 24 hours detorsion. Testis were collected for the analysis of glutathione peroxidase (GPx), nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), and xanthine oxidase (XO).GPx in the Group 8 were higher than the values in the other groups (p < 0.001). Concerning NO, the groups 3, 4, and 7 were found to have higher values than other groups (p < 0.001). MDA levels were higher in the groups 3, 7, and 8, when compared to the levels in other groups (p < 0.001). When tissue GSH levels were examined, the Group 5 had the highest GSH values (p < 0.001).With regard to XO values, the groups 3, 4, and 7 had the highest XO values (p < 0.001). The results of the study indicated that intraperitoneal DiOHF inhibited increased lipid peroxidation in testis ischemia-reperfusion injury in rats (Tab. 5, Ref. 46).

Effect of melatonin on element distribution in the liver tissue of diabetic rats subjected to forced exercise.

The objective of the present study was to investigate the effects of melatonin supplementation on elements in the liver of diabetic rats subjected to acute swimming exercise. Eighty adult male rats were equally divided into eight groups. Group 1, general control. Group 2, melatonin-supplemented control. Group 3, melatonin-supplemented diabetic control. Group 4, swimming control. Group 5, melatonin-supplemented swimming. Group 6, melatonin-supplemented diabetic swimming. Group 7, diabetic swimming. Group 8, diabetic control. Liver tissue samples were analyzed for lead, cobalt, molybdenum, chrome, sulphur, magnesium, manganese, sodium, potassium, phosphorus, copper, iron, calcium, zinc, selenium. The highest cobalt, chrome values were found in the groups 7, 8 and the groups 5, 6 respectively. Groups 3 and 7 had the highest copper values. Iron and potassium values were higher in the groups 1 and 4. Group 6 had increased magnesium value, and groups 6, 7, 8 were found to have the highest manganese levels. The highest lead values were found in the groups 5 and 6. Group 6 had the highest selenium levels. The highest zinc levels were established in 1 and 2. Groups 1, 2, 5 and 6 were found to have the highest calcium values. The results of our study indicate that melatonin supplementation in diabetes and forced exercise significantly alters the element metabolism in the liver (Tab. 3,Ref. 33).

Selenium prevents lipid peroxidation in liver and lung tissues of rats in acute swimming exercise.

BACKGROUND: Selenium, which is critical for human health, is necessary for various metabolic processes, including thyroid hormone metabolism, protection against oxidative stress, and immune function. OBJECTIVE: The present study aims to examine how selenium administration affects lipid peroxidation in liver and lung tissues of rats subjected to acute swimming exercise. METHODS: The study included 32 Spraque-Dawley adult male rats divided into Group 1 (general control), Group 2 (selenium-administered), Group 3 (swimming), and Group 4 (selenium-administered swimming). MDA and GSH levels were determined in liver and lung tissues. RESULTS: The highest MDA values in the liver and lung tissues were found in group 3 in the study. MDA value in group 4 was higher than those in groups 1 and 2. Group 4 had the highest liver and lung GSH levels. GSH levels in Group 3 were higher than those in groups 1 and 2. CONCLUSION: Results of the study indicate that acute swimming exercise causes lipid peroxidation in liver and lung tissues, while selenium administration prevents free radical formation by increasing antioxidant activity (Tab. 2, Ref. 26).

Lipid peroxidation in kidney and testis tissues in experimental hypothyroidism: the role of zinc.

The aim of the present study was to determine the effect of zinc supplementation and zinc deficiency on the lipid peroxidation in the testis and kidney tissues of rats with experimentally induced hypothyroidism. The experimental Groups were formed as follows: 1 - Control; 2 - Sham-Hypothyroidism; 3 - Hypothyroidism (intraperitoneal administration of 10 mg/kg/day PTU for 4 weeks); 4 - Hypothyroidism + 3 mg/kg/day zinc supplementation (4 weeks); 5 - Hypothyroidism + zinc deficiency (4 weeks). The examination of the study results revealed that hypothyroidism in testis and kidney tissues increased MDA levels and decreased GSH levels (p<0.001). Zinc supplementation in addition to hypothyroidism, however, reduced the increased MDA amount and elevated GSH levels (p<0.001). Zinc deficiency together with hypothyroidism, on the other hand, was found to produce the opposite results (p<0.001). The results of the study indicated that experimental hypothyroidism caused lipid peroxidation in kidney and testis tissues. Zinc deficiency together with hypothyroidism made lipid peroxidation more evident, while zinc supplementation significantly inhibited the increased oxidative stress by activating the antioxidant system (Tab. 1, Ref. 24).

L-thyroxine-induced hyperthyroidism affects elements and zinc in rats.

There is a significant relation between thyroid hormones and zinc. The establishment of low blood zinc levels in hypothyroidism as opposed to high blood zinc levels in hyperthyroidism testifies to this relation. The present study aims to examine the changes in levels of some elements in sera of rats with induced hyperthyroidism as well as the relation between these changes and zinc.Thirty adult male rats of Sprague-Dawley type were equally allocated to three groups, particularly Group 1: General Control, Group 2: Sham-hyperthyroidism Group, and Group 3: Hyperthyroidism Group. Subsequent to decapitating the animals, their blood samples were taken and analyzed with the help of atomic emission spectrophotometer in terms of serum levels of zinc, selenium, calcium, magnesium, phosphorus, chromium, copper and iron. The levels of zinc, selenium and calcium were higher (p<0.01), while those of chromium, copper, iron and phosphorus were lower (p<0.01) in Group 3, relative to groups 1 and 2. These parameters were not different in groups 1 and 2.The results obtained from the study indicate that hyperthyroidism brings about some changes in the levels of some elements in rats. These changes might be associated with the elevation of zinc levels in hyperthyroidism (Tab. 2, Ref. 41).

The effect of selenium supplementation on elements distribution in liver of rats subject to strenuous swimming.

The present study aims to explore how selenium supplementation affects the element distribution in the liver tissue of rats subjected to strenuous swimming exercise. Thirty-two Spraque-Dawley male rats were equally divided into the four groups: Group 1, normal control group. Group 2, selenium-supplemented, non-swimming (0.6 mg/kg/day sodium selenite) group. Group 3, swimming, no supplementation group. Group 4, swimming, selenium-supplemented (0.6 mg/kg/day sodium selenite) group. After one month, the animals were decapitated and liver tissue samples were collected to determine the levels of lead, cobalt, boron, molybdenum, chromium, sulfur, magnesium, sodium, potassium, phosphorus, copper, iron, zinc and selenium. The chromium, molybdenum, iron, sodium and potassium values were higher in the swimming groups, relative to controls. Group 3 had significantly lower lead levels (p<0.001). The highest cobalt levels were obtained in the Group 1 and that of the Group 2 was higher than in the Groups 3 and 4. The boron values in the Group 3 were higher than those in all other groups. The copper and magnesium levels were higher in the Groups 3 and 4, compared to the Groups 1 and 2. The highest phosphorus levels were found in the Group 1. The highest selenium and zinc values were obtained in the Group 2 and those of the Group 4 were higher than in the Groups 1 and 3. Group 1 had higher selenium and zinc levels than the Group 3. The results of the present study demonstrated that selenium-supplemented rats subjected to strenuous swimming exercise had distinct elements distribution in liver tissue. Also, selenium supplementation offsets the decrease in zinc levels in rats subjected to vigorous swimming (Tab. 3, Ref. 20).

The effects of resveratrol and melatonin on cardiac dysfunction in diabetic elderly female rats.

We aimed to investigate the effects of melatonin and resveratrol on diabetes-related papillary muscle dysfunction and structural heart disorders. The protective effect of resveratrol and melatonin supplementation on cardiac functions was investigated in a diabetic elderly female rat model. 16-month-old rats (n=48) were allocated into 8 groups. Group1: Control, Group2: Resveratrol Control, Group3: Melatonin Control, Group4: Resveratrol and Melatonin Control, Group5: Diabetes, Group6: Diabetes Resveratrol, Group7: Diabetes Melatonin, Group8: Diabetes Resveratrol and Melatonin. Streptozotocin was injected intraperitoneally to the rats for experimental diabetes induction. Thereafter, resveratrol (intraperitoneal) and melatonin (subcutaneous) were administered for 4 weeks. Resveratrol and melatonin had a protective effect on the contractile parameters and structural properties of the papillary muscle, which was impaired by diabetes. it has been presented that diabetes impairs the contractile function of the papillary muscle for each stimulus frequency tested and the responses obtained as a result of Ca+2 uptake and release mechanisms from the Sarcoplasmic reticulum, and it has been observed that these effects are improved with resveratrol and melatonin injection. The decrease in myocardial papillary muscle strength in the diabetic elderly female rat can be reversed with the combination of resveratrol, melatonin and resveratrol+melatonin. Melatonin+resveratrol supplementation is no different from melatonin and/or resveratrol supplementation. Resveratrol and melatonin supplementation may have a protective effect on cardiac functions in a diabetic elderly female rat model.

Plasma leptin levels in rats with induced Toxoplasma gondii infection.

BACKGROUND: To explore the changes in plasma leptin levels of rats with induced Toxoplasma gondii infection. METHODS: The study was conducted on 20 Spraque-Dawley type adult male rats, which were equally divided into two groups. Group 1, general control group. Group 2, infection group (rats in this group were infected with live Toxoplasma gondii parasite, which was injected in 0.5 ml serum physiologic through intraperitoneal route, so that 10-12 parasites were seen in the area under a light microscope). Blood samples collected from all animals 4 weeks after the infection were analyzed to determine plasma leptin levels (RIA). RESULTS: There was no significant difference between the body weights of groups 1 and 2 at the end of the study. Plasma leptin levels in the infection group (group 2) were significantly higher than those in group 1 (p<0.01). CONCLUSION: Toxoplasma gondii infection can cause an increase in leptin secretion without changing body weight in a period of 4 weeks in rats (Tab. 1, Ref. 25).

The effect of acute swimming exercise on plasma melatonin levels in rats.

BACKGROUND: This study aims to determine the changes in plasma melatonin levels of rats performing acute swimming exercise, immediately following the exercise and after 24 and 48 hours. METHODS: The study included 40 Spraque Dawley species adult male rats divided in to 4 groups as follows: group 1: general control group, group 2: swimming group A, the animals were decapitated after performing 30-minute acute swimming exercise, group 3: Swimming group B, the animals were decapitated 24 hours after performing 30-minute acute swimming exercise and group 4: swimming group C, the animals were decapitated 48 hours after performing 30-minute acute swimming exercise. Blood samples were collected from all experimental animals by decapitation method and plasma melatonin levels were determined according to RIA method. RESULTS: The comparison of plasma melatonin levels among groups revealed that group 3 had the highest plasma melatonin levels (p<0.01). The levels in group 1 (control) and group 4 were not different. The lowest plasma melatonin levels were found in group 2 (p<0.01). CONCLUSION: The results of our study demonstrate that plasma melatonin levels that decrease immediately after acute swimming exercise increase significantly after 24 hours and restore to resting levels after 48 hours (Tab. 1, Ref. 15).

The role of zinc supplementation in the inhibition of tissue damage caused by exposure to electromagnetic field in rat lung and liver tissues.

BACKGROUND: The objective of the present study was to examine the effects of zinc supplementation on the oxidant damage in lung and liver tissues in rats exposed to a 50-Hz frequency magnetic field for 5 minutes every other day over a period of 6 months. METHODS: The study included 24 adult male Sprague-Dawley rats, which were divided into the three groups in equal numbers: Group 1, the control group (G1); Group 2, the group exposed to an electromagnetic field (G2); and Group 3, the group, which was exposed to an EMF and supplemented with zinc (G3). At the end of the 6-month procedures, the animals were decapitated to collect lung and liver tissue samples, in which MDA was analyzed using the "TBARS method (nmol/g/protein)", GSH by the "biuret method (mg/g/protein)" and zinc levels by atomic emission (µg/dl). RESULTS: MDA levels in lung and liver tissues in G2 were higher than those in G1 and G3, and the levels in G3 were higher than those in G1 (p<0.01). As for GSH levels, G3 had GSH levels higher than G1 and G2, and G2 had GSH levels higher than G1 (p<0.01). Zinc values in the liver and lung tissues were the highest in the Group 3 and the lowest in the Group 2 (p<0.01). CONCLUSION: Results of the study indicated that exposure to an electromagnetic field caused cellular damage in lung and liver tissues and zinc supplementation inhibited the inflicted cellular damage. Another important result of this study that needs emphasis was that exposure to an electromagnetic field led to a significant decrease in zinc levels in lung and liver tissues (Tab. 3, Ref. 23).

The effect of acute swimming exercise on plasma leptin in rats.

Exercise is known to increase free fatty acid and glucose metabolism. In consideration of such physiological effects of leptin such as reducing food intake and increasing energy consumption, many researchers have studied the relation between leptin and exercise. Despite the inconsistency between results, it is generally accepted that physical activity causes changes in leptin secretion. The present study aims to determine the changes that occur in plasma leptin levels of the rats subjected to acute swimming exercise, immediately after exercise, and in the 24th and 48th hours following exercise.Forty adult male rats of Spraque Dawley species were equally allocated to 4 groups. Group 1: General Control Group. Group 2: Swimming Group, the group that was decapitated just after 30-minutes of acute swimming exercise. Group 3: Swimming Group, the group that was decapitated 24 hours after 30-minutes of acute swimming exercise. Group 4: Swimming Group, the group that was decapitated 48 hours after 30-minutes of acute swimming exercise. Plasma leptin levels of the experimental animals were determined according to RIA method in the blood samples collected by decapitation method. Comparison of plasma leptin levels between groups revealed that the Group 3 had the highest plasma leptin levels (p <0.01). Plasma leptin levels in the Group 1 (control) and 4 were not different and the Group 2 had the lowest plasma leptin levels (p <0.01). Results of the present study show that an acute swimming exercise and/or stress factors associated with an acute exercise inhibit leptin secretion from the adipose tissue (Tab. 1, Ref. 21).

Effect of zinc supplementation on lipid peroxidation and lactate levels in rats with diabetes induced by streptozotocin and subjected to acute swimming exercise.

OBJECTIVE: The present study aims to explore the effect of zinc supplementation on lipid peroxidation and lactate levels in rats having diabetes induced by streptozotocin and subjected to acute swimming exercise. METHOD: A total of 80 adult male rats of Sprague-Dawley type were equally allocated to 8 groups: Group 1, general control. Group 2, zinc-supplemented group. Group 3, zinc-supplemented, diabetic group. Group 4, swimming control group. Group 5, zinc-supplemented swimming group. Group 6, zinc-supplemented diabetic swimming group. Group 7, diabetic swimming group. Group 8, diabetic group. At the end of the 4-week study, blood samples were collected to determine MDA, GSH, GPx, SOD, lactate and zinc levels. RESULTS: The highest MDA values were found in group 7 and 8 (p<0.001). GSH values in groups 5 and 6 were higher (p<0.001). The highest GPx values were established in groups 2, 5 and 6 (p<0.001). SOD values were the highest in groups 5 and 6 (p<0.001) and lowest in groups 2, 3 and 8 (p<0.001). The highest plasma lactate levels were found in group 7 (p<0.001). The highest zinc levels were obtained in groups 1, 2 and 5 (p<0.001), and the lowest zinc levels were found in groups 7 and 8 (p<0.001). CONCLUSION: Results of the study reveal that zinc supplementation prevents the increase of free radical formation, suppression of antioxidant activity and muscle exhaustion, all of which result from diabetes and acute exercise. Zinc supplementation may contribute to health performance in diabetes and acute exercise (Tab. 2, Fig. 1 Ref. 47). Full Text in PDF www.elis.sk.

Protective effect of melatonin on lipid peroxidation in various tissues of diabetic rats subjected to an acute swimming exercise.

BACKGROUND: The present study aimed to explore the effect of melatonin administration on lipid peroxidation in various tissues of rats with streptozocin induced diabetes and subjected to an acute swimming exercise. METHODS: The study used 80 adult male rats, which were equally allocated to 8 groups: Group 1, general control; Group 2, melatonin-administered control; Group 3, melatonin-administered diabetic control; Group 4, swimming control; Group 5, melatonin-administered swimming; Group 6, melatonin-administered diabetic swimming; Group 7, diabetic swimming; Group 8, diabetic control. Diabetic rats were administered 3 mg/kg/day ip melatonin for 4 weeks. At the end of the study, the animals were decapitated to collect samples from liver, lung and spleen tissues, which were then analyzed to determine levels of liver MDA (nmol/gram/protein) and GSH (mg/g/protein). RESULTS: The highest MDA values in liver, lung and spleen tissues were obtained in the Group 7. The values in the Group 8 were lower than those in the Group 7, but higher than in all other groups. The Group 5 and 6 had the highest liver, lung and spleen GSH values. CONCLUSION: Results obtained from the study indicate that the increase in free radical production and the inhibition of antioxidant activity in diabetes and acute exercise are both prevented by melatonin administration (Tab. 2, Ref. 30).

Selenium supplementation prevents lipid peroxidation caused by arduous exercise in rat brain tissue.

BACKGROUND: The objective of the present study is to examine how selenium supplementation affects lipid peroxidation in the brain tissue of rats subjected to acute swimming exercise. METHODS: The study was carried out on 32 Spraque-Dawley adult male rats, which were allocated equally to four groups, namely general control (Group 1), selenium-supplemented control (0.6 mg/kg/day sodium selenite) (Group 2), swimming control (Group 3), and selenium-supplemented swimming group (6 mg/kg/day sodium selenite) (Group 4). Selenium supplementations were carried out by intraperitoneal (i.p.) route for four weeks. At the end of supplementation, animals in groups 3 and 4 were subjected to acute swimming. Brain tissue samples were collected from decapitated animals to determine malondialdehyde (MDA) levels using a spectrophotometer according to "Schimadzu-1601, Japan" Uchiyama and Mihara and GSH levels using a spectrophotometer according to Ellmann. RESULTS: The highest MDA values in the brain tissue were obtained in Group 3 (p < 0.001). MDA values in Group 4 were higher than those in Groups 1 and 2 (p < 0.001). Brain tissue MDA values in Groups 1 and 2 did not differ. Group 4 had the highest brain GSH levels (p < 0.001). Brain tissue glutathione (GSH) levels in Group 3 were higher than those in Groups 1 and 2 (p < 0.001). CONCLUSION: Results of the study indicate that acute swimming exercise in rats increased the lipid peroxidation in the brain tissue of rats, while selenium supplementation prevented the free-radical formation by enhancing the antioxidant activity (Tab. 1, Ref. 24).

Effect of boron supplementation on plasma element distribution in ovariectomized rats subjected to acute swimming exercise.

BACKGROUND: This study aims to examine how boron supplementation affects distribution of elements in the plasma of rats whose ovaries were removed and who were subjected to swimming exercise. METHODS: The study included 80 Sprague-Dawley type female rats, which were equally allocated to 8 groups. Group 1: General control, Group 2: Exercise control; Group 3: Ovariectomized control, Group 4: Ovariectomized exercise, Group 5: IP (intraperitoneal) boron-supplemented control, Group 6: IP boron-supplemented exercise, Group 7: Ovariectomized, IP boron-supplemented exercise, group 8: Ovariectomized, IP boron-supplemented. Following the exercise, blood samples were collected from all animals by decapitation, and analyzed in terms of plasma copper, iron, phosphorus, magnesium, calcium, and zinc using an atomic absorption spectrophotometer. RESULTS: Groups 1 and 5 had the lowest copper (p < 0.01) and the highest zinc and calcium (p < 0.01) levels, in comparison to other groups. Phosphorus levels in groups 3, 5 and 8 were significantly lower than those in other groups (p < 0.01). Magnesium levels in groups 3, 5 and 8 were higher, relative to the levels in other groups (p < 0.01). CONCLUSION: Results of the study indicate that acute swimming exercise in ovariectomized rats supplemented with boron leads to significant modifications in the distribution of some trace elements in the plasma. It can be emphasized as a separate result of this study that changes in copper, zinc and calcium levels were independent of boron supplementation (Tab. 2, Ref. 14).

Histological effects of zinc and melatonin on rat testes.

BACKGROUND: The objective of this study is to examine the histological effects of zinc and melatonin, alone or in combination, on rat testes. METHODS: For this purpose four study groups of ten Sprague-Dawley male rats were formed and treated for one month as follows: (1) Controls; (2) Rats injected with 3 mg/kg/day zinc, as zinc sulfate; (3) Rats injected with 3 mg/kg/day melatonin and (4) Rats injected with 3 mg/kg/day each zinc and melatonin. RESULTS: After four weeks the rats treated with melatonin showed inhibited spermatogenesis, testicular tubular degeneration and necrosis, obstruction of tubular lumen and lymphocytic infiltration. The two zinc-treated groups showed no histological differences to controls but the melatonin-only group showed inhibited spermatogenetic activity, tubular degeneration and necrosis, as well as obstruction of tubule lumens and lymphocytic infiltration. CONCLUSION: The obtained results suggest that 4-week treatment with melatonin leads to histological and physiological impairments of testis and that zinc supplementation might offset these damaging effects (Tab. 2, Fig. 4, Ref. 12).

Influences of hypertonic and hypovolemic treatments on vasopressin response in propylthiouracil (PTU) induced hypothyroid rat and effect on supplementation with L-thyroxine.

This study was performed to investigate the effects of L-thyroxine treatment on plasma vasopressin (AVP) levels in rats with hypothyroidism induced by propylthiouracil (PTU). Animals were separated into three groups each having 6 rats: control, PTU, PTU+L-thyroxine groups. Then, the groups were further divided into 3 sub-groups including 6 rats (a; basal, b; hypertonic stimulated and c; hypovolemic stimulated). At the end of the experiments all rats were decapitated in order to obtain plasma samples for analysis in terms of Hct, osmolality, TT 3 , TT 4 and vasopressin. Haematocrit (Hct) levels were the highest in hypovolemic stimulated sub-group (P < 0.001). Osmolality levels were higher in hypertonic stimulated sub-groups (P < 0.001). Total T 3 and T 4 values were the lowest in the PTU group and the highest in the L-thyroxine treated group (P < 0.001). Plasma AVP levels were reduced by hypothyroidism. However, L-thyroxine treatment after the hypothyroidism prevented this reduction (P < 0.001). Vasopressin responses to basal, hypovolemic and hypertonic stimulations were the lowest in the PTU group (P < 0.001). The results of the present study show that basal and stimulated plasma vasopressin levels are reduced in PTU-induced hypothyroidism. However, L-thyroxine treatment following hypothyroidism prevents this reduction.