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Journal Article 2005; 26(6): 663-666 PubMed PMID: 16380693 Citation  Keywords:  Adult, Apoptosis:physiology, Endometrium:metabolism, Female, Humans, Immunohistochemistry, Menstrual Cycle:metabolism, Metallothionein:metabolism, Middle Aged, Statistics, Nonparametric,.   

OBJECTIVES: Molecular changes observed in endometrium with respect to menstrual cycle changes seem to be crucial for the reproductive function. Accumulation of cytotoxic cells increases the exposure of endometrial cells to apoptosis. Protection against apoptosis may be reached by endometrial cells by self molecular regulation. Metallothionein was suggested to participate in this process. The aim of our study was to evaluate endometrial MT immunoreactivity with respect to the menstrual cycle phases.

MATERIALS AND METHODS: MT expression was assessed using immunohistochemistry method in 47 endometrial tissue samples derived from randomly selected patients with respect to the menstrual cycle phases--proliferative and secretory with distinguishing early, mid and late subphases in each.

RESULTS: MT expression changes were observed respectively to hormonal fluctuations with the highest level during mid secretory phase and its respective decrease during the early, late secretory and mid proliferative menstrual cycle phases. The lowest MT immunoreactivity level was disclosed during early proliferative phase.

CONCLUSION: Significant differences in MT expression observed in endometrium with respect to menstrual cycle changes might suggest MT participation in endometrial cells protection against apoptosis....

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Comparative Study 2005; 26(6): 780-788 PubMed PMID: 16380692 Citation  Keywords:  Age Factors, Animals, Animals, Newborn:physiology, Body Weight:physiology, Corticosterone:blood, Female, Germ Cells:cytology, Hydroxysteroid Dehydrogenases:metabolism, Hypothyroidism:chemically induced, Luteinizing Hormone:blood, Male, Organ Size, Pregnan.   

OBJECTIVE: Effects of transient neonatal hypothyroidism (HPOT) on adult testis size and serum hormone profiles were evaluated in the Charles foster strain of rats, maintained under the temperature of 21 degrees C (HPOTL) or of 34 degrees C (HPOTH).

METHODS: Hypothyroidism was induced in suckling pups in preweanling period (1-21 days), by administering 0.1% 6-propyl-2-thiouracil in drinking water to mothers. Body mass and testis characteristics, the steroidogenic potential [measured by histochemical localization of 3alpha-, 3beta- and 17beta-hydroxysteroid dehydrogenases (HSDHs)] and serum concentrations of thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), luteinizing hormone (LH), testosterone (T) and corticosterone (Cort) were evaluated on the 35th, 45th, 60th and 90th day of age.

RESULTS: The HPOTH rats showed lower testis masses, while the HPOTL rats showed higher testis masses and lower body masses after 90 days. Histologically, the testes of the HPOTH rats demonstrated increased germ cell degeneration after 35 and 45 days and reduced tubular size, germ cell numbers and sperm density after 90 days. In contrast, the testes of the HPOTL rats showed reduced tubular diameters after 35 and 45 days, and increased tubular diameters, germ cell numbers and sperm density after 90 days. Serum TSH, T3, T4, LH and T concentrations and 3beta- and 17beta-HSDH activities were reduced in both groups of the HPOT rats after 35 and 45 days. Intratubular steroidogenesis and a prominent triangle up5 pathway were also found in the HPOT animals.

CONCLUSION: The temperature has a definite influence on the thyroid hormone action, postnatal growth and function of rat testes....

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Journal Article 2005; 26(6): 799-805 PubMed PMID: 16380691 Citation  Keywords:  Chromatography, High Pressure Liquid, Dihydropyridines:analysis, Histamine:chemistry, Malondialdehyde:chemistry, Neurotoxins:chemistry, Nitrogen Compounds:analysis, Protein Carbonylation,.   

OBJECTIVES: To explore the mechanism of carbonyl stress-related toxification on neurotransmitter histamine and the potential de-carbonylation function of histamine.

METHODS: The reaction mixture of malondialdehyde (MDA) and histamine (HA) at pH7.4, 37 degrees C was assayed by high performance liquid chromatography (HPLC), spectrophotometry and spectrofluorometry. The reaction products were assayed by LC/MS.

RESULTS: In physiological condition, the reaction of MDA and HA yielded two products: a nonfluorescent enaminal derivatives and a fluorescent 1,4-dihydropyridine adducts. The fluorescence maxima of the fluorescent products (Ex. 393 nm/Em. 464 nm) were similar to those of lipofuscin pigment. The fluorescence intensity of reaction mixture was in direct proportion to the MDA concentration.

CONCLUSIONS: HA can react with MDA to form stable products, a non-fluorescent enamine (product 1) and a fluorescent 1,4-dihydropyridine (product 2) which are ceroid/lipofuscin-related adducts. The reaction of HA with MDA may reveal toxic effect of unsaturated carbonyls in the brain and may reflect a novel de-carbonylation function of histamine under various pathological conditions....

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Comparative Study 2005; 26(6): 719-723 PubMed PMID: 16380689 Citation  Keywords:  Adaptation, Physiological, Adrenal Glands:enzymology, Animals, Electron Transport Complex IV:biosynthesis, Enzyme Induction:drug effects, Hypothalamo-Hypophyseal System:physiopathology, Liver Circulation:drug effects, Liver Cirrhosis, Experimental:chemica.   

OBJECTIVES: Cytochrome oxidase activity has been determined in the adrenal glands of thioacetamide (TAA)-cirrhotic rats.

MATERIAL AND METHODS: Two groups of animals (Control group; n=10 and TAA group; n=11) of three months evolution were used to study the cytochrome oxidase activity in the suprarenal cortex (glomerular, fascicular and reticular layers) and medulla. TAA was administered orally and cytochrome oxidase (COX) activity was assayed by an immunohistochemical technique.

RESULTS: In TAA-cirrhotic rats, COX activity increases in the cortex fascicular layer (221 +/- 1.79 vs 181.9 +/- 2.75; p<0.001) as well as in the medulla (146.6 +/- 1.72 vs 129 +/- 3.09; p<0.001).

CONCLUSION: These results make it possible to consider the existence of hypothalamic-pituitary-adrenal-axis and adrenomedullary sympathetic system hyperactivity, both peripheral limbs of the stress system, in this experimental model of cirrhosis....

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Comparative Study 2005; 26(6): 795-798 PubMed PMID: 16380688 Citation  Keywords:  Animals, Antioxidants:metabolism, Brain:enzymology, Glutathione:metabolism, Hyperthyroidism:metabolism, Lipid Peroxidation:physiology, Liver:enzymology, Male, Malondialdehyde:metabolism, Myocardium:enzymology, Pineal Gland:physiology, Rats, Rats, Sprague-.   

OBJECTIVE: Thyroid hormones regulate energy metabolism and act on the mitochondria, which is an important source of free radicals in the cell. Reactive oxygen types play a significant role in physiological mechanisms, but in excessive amounts they can cause oxidative damage in molecules. The aim of the present study was to determine levels of lipid peroxidation caused by induced hyperthyroidism in cerebral, hepatic and cardiac tissues of pinealectomized rats.

METHODS: Experimental animals used in the study were allocated to three groups as general control group, hyperthyroidism-sham pinealectomy group and hyperthyroidism-pinealectomy group. GSH and MDA levels in cerebral, hepatic and cardiac tissues were evaluated at the end of the 3-week study period.

RESULTS: It was found that MDA levels in cerebral, hepatic and cardiac tissues were the highest in hyperthyroidism and pinealectomy group and that these values were higher in hyperthyroidism-sham pinealectomy group than in the control group (p<0.001). It was seen that tissue GSH levels significantly increased in hyperthyroidism-sham pinealectomy group (p<0.001) and that the increase in hyperthyroidism and pinealectomy group was higher than the increase in the control group only (p<0.001).

CONCLUSION: Results of our study show that MDA and GSH levels in cerebral, hepatic and cardiac tissues increased due to hyperthyroidism and that the increase in MDA levels became more evident and GSH levels were significantly suppressed after pinealectomy....

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Comparative Study 2005; 26(6): 806-810 PubMed PMID: 16380687 Citation  Keywords:  Animals, Glutathione:metabolism, Hyperthyroidism:chemically induced, Kidney:metabolism, Lipid Peroxidation, Male, Malondialdehyde:metabolism, Melatonin:metabolism, Oxidative Stress:physiology, Rats, Rats, Sprague-Dawley, Testis:metabolism, Thyroxine,.   

OBJECTIVE: The present study aimed at determining how 3-week intraperitoneal melatonin administration affected oxidative stress caused by experimental hyperthyroidism.

MATERIALS AND METHODS: The study was conducted on 30 male rats of Sprague-Dawley species. The experimental animals were divided to 3 groups (control, hyperthyroidism and hyperthyroidism+melatonin). The supplementation was continued for 3 weeks after which the animals were sacrificed and tissue malondyaldehyde (MDA) and glutathione (GSH) levels were determined.

RESULTS: MDA levels in kidney and testis tissues in hyperthyroidism group were higher than those in control and hyperthyroidism+melatonin administered groups (p<0.001) and levels in hyperthyroidism+melatonin administered group were higher than those in the control group (p<0.001). The highest GSH levels were obtained in hyperthyroidism+melatonin-administered group (p<0.001) and GSH levels in hyperthyroidism group were higher than those in the control group (p<0.001).

CONCLUSION: Results of the study demonstrate that hyperthyroidism induced by 3-week L-thyroxine administration increased oxidative stress in kidney and testis tissues and that although melatonin administration inhibited this stress to a certain extent, it could not bring the stress down to the level in controls....

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Comparative Study 2005; 26(6): 729-732 PubMed PMID: 16380686 Citation  Keywords:  Age Factors, Animals, Animals, Newborn, Longitudinal Studies, Male, Organ Size:drug effects, Rats, Rats, Sprague-Dawley, Selective Estrogen Receptor Modulators:pharmacology, Sexual Behavior, Animal:drug effects, Tamoxifen:pharmacology, Testis:cytology, Te.   

OBJECTIVE: In this study we examined the possibility that demasculinization produced by the neonatal administration of tamoxifen is accompanied by a decline in plasma levels of testosterone during adulthood.

METHODS: Wistar male rats received either a treatment with 12.5 microg/kg of tamoxifen during the first eight days of age or a treatment with 100 microg/kg of tamoxifen for five days. Each treatment had their respective control group. During adulthood their masculine sexual behavior was analyzed. At 8 months of age, males were killed by decapitation, trunk blood was collected and peripheral glands were dissected and weighed. Testosterone levels were measured by HPLC. Histological analysis of peripheral glands was performed.

RESULTS: Both neonatal tamoxifen treatments significantly decreased male sexual behavior when compared to control values. In addition, both treatments also showed a significant decrease in testicular weight when compared to control groups, as well as a decrease in seminal vesicle weight. In the microscopic analysis, a significant decrease in the diameter of the seminiferous tubules was observed, especially in the animals treated with 100 microg/kg of tamoxifen. However, no differences were observed between tamoxifen treated and control animals concerning plasma levels of testosterone.

CONCLUSION: The present results indicate that behavioral manifestations and changes in peripheral reproductive organs that accompanied demasculinization are not due to a deficit in testosterone secretion....

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Clinical Trial 2005; 26(6): 771-774 PubMed PMID: 16380685 Citation  Keywords:  Adaptation, Psychological, Adolescent, Adult, Analysis of Variance, Cultural Evolution, Female, Hierarchy, Social, Homosexuality, Humans, Male, Psychological Theory, Reproduction, Sex Factors, Sexual Behavior:psychology, Social Behavior,.   

OBJECTIVES: The alliance theory holds that homosexual behavior in humans may have evolved because it reinforced same-sex alliances which contributed to survival and reproduction. The present study was designed to test this evolutionary hypothesis in view of the strongly negative perception of homosexual behavior. It was predicted that targets who engaged in homosexual behavior would be perceived as likely to achieve greater social status and reproductive opportunities when the behavior reinforced an alliance that led to increased social opportunities.

METHODS: Three hundred sixteen men and women read scenarios in which a target engaged in homosexual behavior and then answered questions about the target's future social status and reproductive opportunities as measured by number of sexual partners. The data were analyzed in two 3 (social outcome: positive vs. neutral vs. negative) x 2 (gender of target) x 2 (gender of participant) analyses of variance.

RESULTS: The results supported the predictions and demonstrated that targets were perceived as likely to have the greatest social status and reproductive opportunities in the positive outcome condition.

CONCLUSION: The alliance theory of homosexual behavior may have heuristic value for the evolutionary study of homosexual behavior and its perception....

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