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  • Author: Svetlana Trifunović x
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Open access

Svetlana Trifunović and Verica Milošević

Abstract

Phytoestrogens are a diverse group of steroid–like compounds that occur naturally in many plants. There are various types of phytoestrogens, including the best-researched isoflavones which are commonly found in soy. The consumption of soy products has many health benefits, including protection against breast cancer, prostate cancer, menopausal symptoms, heart disease and osteoporosis. In contrast, use of hormonally active compounds-isoflavones may unfortunately interfere with the endocrine system and can have far-reaching consequences. Genistein, the most abundant soy-bean derived isoflavone, possesses a ring system similar to estrogens and acts through an estrogen receptor (ER)-mediated mechanism, by increasing or decreasing the transcription of ER-dependent target genes. Also, genistein can act on cells through ER non-dependent mechanisms, such as tyrosine kinase inhibitor. The neuroendocrine systems are responsible for the control of homeostatic processes in the body, including reproduction, growth, metabolism and energy balance, and stress responsiveness. It is well known, that estrogen is important for development of the neuroendocrine system in both sexes. At the pituitary level, estrogen is known to affect the regulation of all hormone producing (HP) cells, by direct and/or indirect mechanisms. Due to structural and functional resemblance to estrogen, the question may arise of whether and how genistein affects the morphofunctional features of pituitary HP cells. This review deals with the consequences of genistein’s effects on morphological, stereological and hormonal features of HP cells within the anterior pituitary gland. Transparency on this issue is needed because isoflavones are presently highly consumed. Inter alia, genistein as well as other isoflavones, are present in various dietary supplements and generally promoted as an accepted alternative to estrogen replacement therapy. Potential isoflavone biomedical exploitation is not only limited to estrogen replacement therapy, so it should be treated in a wider context of different ageing symptoms remediation.

Open access

Natasa Ristic, Vladimir Ajdzanovic, Svetlana Trifunovic, Nasta Tanic, Nada Bujisic and Verica Milosevic

Abstract

The effects of estradiol-dipropionate (EDP) or human chorionic gonadotropin (hCG) on immunohistomorphometric characteristics of pituitary GH cells in infant and peripubertal female rats were investigated. The first group of females received five injections of EDP (0.25 mg/kg b.w.) during the neonatal period of life, and was further divided into two subgroups which were sacrificed at the infantile period (17th day) or at the peripubertal period (38th day). The second group received two doses of hCG (50 IU/kg b.w.) on the 15th and 16th day of life in the first subgroup, and on the 36th and 37th days of life in the second subgroup, while they were sacrificed 24 h after the last treatment, respectively. The control females were injected with an equivalent volume of the vehicle and sacrificed according to the appropriate schedules as the hormone treated rats. EDP treatment decreased GH cell volume density in infant and peripubertal females, by 38% and 76% (p<0.05) respectively, in comparison with the controls. The number of GH cells per mm2 in infantile and peripubertal period was decreased in EDP treated animals by 26% and 53% (p<0.05) respectively, compared to the controls. Also, upon EDP treatment in both periods, GH cells were diminished in size and less intensely immunolabelled than in the control groups. The morphometric parameters in animals treated with hCG were insignificantly changed in both analyzed periods, in comparison with the controls. Unlike hCG, EDP manifested clear inhibitory effects on the immunohistomorphometric characteristics of GH cells in examined female rats.

Open access

Florina Popovska-Perčinić, Ivana Jarić, Lazo Pendovski, Ristić Nataša, Svetlana Trifunović, Verica Milošević and Vladimir Ajdžanović

Abstract

In areas with moderate continental climate, increased average ambient temperature during the summer represents a stressogenic factor that affects the hypothalamo-pituitaryadrenocortical axis in mammals. Therefore, we wanted to examine the effects of 4 days of constant exposure to moderately elevated ambient temperature (35 ± 1oC) on the histomorphometric and immunofl uorescent characteristics, as well as on the hormonal secretion of pituitary corticotropes (ACTH) cells in adult male rats. In comparison with the controls kept at 20 ± 2oC, a signifi cant increase (p<0.05) of the absolute and relative pituitary weight (23.1% and 36.1%, respectively) was registered after exposure to heat. The localization, as well as the shape of the ACTH cells in the heat exposed group was not signifi cantly altered, but their immunopositivity was weaker. After 4 days of heat exposure, a weaker signal confi rmed the relative fl uorescence intensity of the ACTH cells (15.3%, p<0.05). In heat exposed rats, an increase of the cellular and nuclear volumes of immunolabelled ACTH cells and decrease of their volume density (6.9%, 14.3% and 20.0%, respectively; p<0.05) was registered. Observed histomorphometric and immunofl uorescent features of the pituitary ACTH cells were in accordance with the increased (p<0.05) value of plasma adrenocorticotropic hormone (ACTH) by 23.7% compared to the control rats. It can be concluded that the 4-day exposure to moderately elevated ambient temperature intensifi es pituitary ACTH secretion in adult male rats.

Open access

Florina Perčinić-Popovska, Vladimir Ajdžanović, Suzana Dinevska-Kofkarovska, Maja Jordanova, Svetlana Trifunović, Branka Šošić-Jurjević and Verica Milošević

Morphofunctional Characteristics of Pituitary Adrenocorticotropes in An Animal Model of Heat Stress

As a result of the global warming, the average ambient temperature during summertime has increased in regions with moderate continental cli mate. The effects of 24 h exposure to heat stress (35±1 °C) on the morphology and function of pituitary adrenocorticotropes were examined in adult male Wistar rats. Significant changes in the morphofunctional features of adrenocorticotropes were found after the heat stress, with no differences noted in the cell shape or localization, compared to controls. The adrenocorticotropes cell volume, as well as the volume density, were significantly decreased (p<0.05) by 12.3% and 26.7%, respectively, in comparison with controls. The concentration of plasma adrenocorticotropic hormone and serum corticosterone in the heat stressed group were significantly decreased (p<0.05) by 21.9% and 27.2%, respectively, compared to controls. These findings suggest that 24 h exposure of adult male rats to heat stress has an inhibitory effect on the morphofunctional characteristics of adrenocorticotropes.

Open access

Vladimir Ajdžanović, Ivana Medigović, Jasmina Živanović, Branka Šošić-Jurjević, Svetlana Trifunović, Nasta Tanić and Verica Milošević

Abstract

Somatopause, the complex aspect of andropause, is recognizable by reduced growth hormone - GH/insulin-like growth factor 1 axis function in the ageing male. Soy isoflavones (usually genistein and daidzein), which are known for their beneficial effects in the treatment of ageing symptoms, are active in the pituitary, as well. The immunohistomorphometric and -fluorescent characteristics of pituitary growth hormone secreting cells, in an animal model of andropause, were examined after a treatment with genistein or daidzein. Andropausal Wistar rats were divided into sham operated, orchidectomized and genistein or daidzein treated orchidectomized groups. Genistein or daidzein (30 mg/kg/day) were administered subcutaneously for three weeks, while sham operated and orchidectomized groups received the vehicle alone. Growth hormone secreting cells were identified by the peroxidase-antiperoxidase immuno-histochemical, and immuno-fluorescent procedure. The main characteristic of growth hormone secreting cells in soy isoflavones treated groups is a weaker immuno-histochemical staining and immuno-fluorescent signal compared to sham operated and orchidectomized groups. The growth hormone secreting cell volume in orchidectomized +genistein or +daidzein groups is by 13.8% and 11.9% (p<0.05) smaller respectively, in comparison with the orchidectomized group. In orchidectomized +genistein or +daidzein groups, the growth hormone secreting cells relative volume density is by 62.5% and 61.0% lower (p<0.05) respectively than for the sham operated group, and decreased by 65.4% and 64.0% (p<0.05) respectively, compared to the orchidectomized group. It can be concluded that chronic genistein or daidzein treatment, in an animal model of andropause, attenuates immunohistomorphometric and -fluorescent characteristics of growth hormone secreting cells.

Open access

Vesna Škodrić-Trifunović, Ana Blanka, Mihailo I. Stjepanović, Svetlana Ignjatović, Violeta Mihailović-Vučinić, Zorica Šumarac, Ivana Buha and Katarina Ilić

Summary

Vitamin D has an important role in numerous physiological functions. Vitamin D receptors are characterized by polymorphisms and presence in different tissues including a number of cells of the immune system. The role of vitamin D as a biological inhibitor of inflammatory hyperactivity is of particular importance. Hypovitaminosis D has been associated with many serious chronic diseases, such as autoimmune, infectious and cardiovascular diseases as well as some types of cancer. Vitamin D has an influence on the immune res ponse to tuberculosis. Calcitriol (1,25-dihydro xycholecalciferol), the major active form of vitamin D, has shown in vitro activity against Mycobacterium tuberculosis. It has been found that susceptibility to chronic mycobacterial infections is strongly correlated with a low vi tamin D intake and particular VDR alleles. Vitamin D deficiency might predispose the individuals infected with Myco bacterium tuberculosis to develop tu-ber culosis. Calcitriol binds to vitamin D receptors and modulates immune responses by regulating the transcription of genes responsive to vitamin D. Faster conversion of sputum mycobacterial culture in patients with pulmonary tuberculosis is associated with being a carrier of the t allele of the T a q I vitamin D receptor polymorphism. On the contrary, slower spu tum culture conversion in pulmonary tuberculosis has been found in the carriers of the f allele of the FokI vitamin D receptor polymorphism. The results of in vitro studies, clini-cal research and population studies indicated that vitamin D deficiency might be a strong risk factor for developing TB. Vitamin D is an inexpensive, easily accessible vitamin, relevant for the prevention of tuberculosis. In addition, vitamin D could contribute to the success of tuberculosis treatment.