Pituitary hormone-producing cells after estradiol application in rat models of menopause

Female ageing represents the biological process of structural and functional changes in endocrine cells and tissues, as well as in pituitary hormone-producing cells. In addition to the hypothalamic releasing hormones, estradiol plays a significant role in the regulation of the synthesis/secretion of pituitary hormones and is still used therapeutically for menopausal symptoms. The effects of ageing or ovariectomy and synthetic estradiol application under these circumstances were evaluated in pituitary hormone-producing cells of female rats (animal models of menopause); i.e., the following cells were observed: gonadotropes (FSH and LH), thyrotropes (TSH), somatotropes (GH), mammotropes (PRL) and corticotropes (ACTH). The cells were immunostained and histologically analysed. The ELISA method was used for hormonal analyses. Ageing was found to cause diverse, commonly reductive changes regarding the volume, number and secretion of menopausal rat pituitary hormone- producing cells, except for PRL cells that exhibit significantly increased numbers and intensified secretion. After the treatment of middle-aged female rats with estradiol, the absolute and relative pituitary weights significantly increased in comparison with the control females. Histological parameters such as the cell and volume density of PRL and ACTH cells were significantly increased compared with the control values. The mentioned parameters of FSH, LH, GH, and occasionally TSH cells after estradiol treatment significantly decreased in comparison with the controls. The corresponding hormone levels followed the changes in the histological parameters. These data indicate that the application of estradiol to menopausal females may specifically, in two directions, modify the histological characteristics and secretory activities of different pituitary-hormone producing cells.Starenje kod ženskog pola je biološki proces tokom kojeg dolazi do promena u strukturi i funkciji endokrinih ćelija i tkiva, a posebnu osetljivost ispoljavaju hipofizne hormonprodukujuće ćelije. Pored oslobađajućih hormona hipotalamusa i estradiol ostvaruje zapaženu ulogu u regulaciji sinteze i sekrecije hipofiznih hormona, a još uvek se koristi u terapiji menopauzalnih tegoba. Efekti starenja ili ovarijektomije, kao i primene sintetskog estradiola pod tim okolnostima su ispitivani na hormon-produkujućim ćelijama hipofize ženki pacova srednjeg doba (animalni modeli menopauze) i to: gonadotropima (FSH i LH), tirotropima (TSH), somatotropima (GH), mamotropima (PRL) i kortikotropima (ACTH). Sve ćelije su imunohistohemijski bojene i histološki analizirane, dok je za određivanje nivoa hormona u krvi korišćena ELISA metoda. Utvrđeno je da starenje prouzrokuje različite, uglavnom reduktivne promene volumena, broja i sekrecije hormon-produkujućih ćelija hipofize u našim animalnim modelima menopauze, izuzev na primeru PRL ćelija čiji je broj značajno povećan, a sekrecija intenzivirana. Posle tretmana ženki pacova srednjeg doba estradiolom apsolutna i relativna masa hipofize je značajno povećana u poređenju sa kontrolnim ženkama. Histološki parametri poput volumena ćelija i volumenske gustine PRL i ACTH ćelija su značajno povećani u poređenju sa kontrolnim vrednostima. Sa druge strane, pomenuti parametri u FSH, LH i GH, a u izvesnim slučajevima i TSH ćelijama su značajno smanjeni nakon tretmana estradiolom, u poređenju sa kontrolama. Koncentracije odgovarajućih hormona u krvi su pratile navedene promene histoloških parametara. Ova zapažanja ukazuju da estradiol davan menopauzalnim jedinkama ženskog pola može na specifičan način, dvosmerno, modifikovati histološke karakteristike i sekretornu aktivnost različitih hormon-produkujućih ćelija hipofize.Projekat ministarstva br. 17300

Pituitary hormone-producing cells after estradiol application in rat models of menopause

Female ageing represents the biological process of structural and functional changes in endocrine cells and tissues, as well as in pituitary hormone-producing cells. In addition to the hypothalamic releasing hormones, estradiol plays a significant role in the regulation of the synthesis/secretion of pituitary hormones and is still used therapeutically for menopausal symptoms. The effects of ageing or ovariectomy and synthetic estradiol application under these circumstances were evaluated in pituitary hormone-producing cells of female rats (animal models of menopause); i.e., the following cells were observed: gonadotropes (FSH and LH), thyrotropes (TSH), somatotropes (GH), mammotropes (PRL) and corticotropes (ACTH). The cells were immunostained and histologically analysed. The ELISA method was used for hormonal analyses. Ageing was found to cause diverse, commonly reductive changes regarding the volume, number and secretion of menopausal rat pituitary hormone- producing cells, except for PRL cells that exhibit significantly increased numbers and intensified secretion. After the treatment of middle-aged female rats with estradiol, the absolute and relative pituitary weights significantly increased in comparison with the control females. Histological parameters such as the cell and volume density of PRL and ACTH cells were significantly increased compared with the control values. The mentioned parameters of FSH, LH, GH, and occasionally TSH cells after estradiol treatment significantly decreased in comparison with the controls. The corresponding hormone levels followed the changes in the histological parameters. These data indicate that the application of estradiol to menopausal females may specifically, in two directions, modify the histological characteristics and secretory activities of different pituitary-hormone producing cells.Starenje kod ženskog pola je biološki proces tokom kojeg dolazi do promena u strukturi i funkciji endokrinih ćelija i tkiva, a posebnu osetljivost ispoljavaju hipofizne hormonprodukujuće ćelije. Pored oslobađajućih hormona hipotalamusa i estradiol ostvaruje zapaženu ulogu u regulaciji sinteze i sekrecije hipofiznih hormona, a još uvek se koristi u terapiji menopauzalnih tegoba. Efekti starenja ili ovarijektomije, kao i primene sintetskog estradiola pod tim okolnostima su ispitivani na hormon-produkujućim ćelijama hipofize ženki pacova srednjeg doba (animalni modeli menopauze) i to: gonadotropima (FSH i LH), tirotropima (TSH), somatotropima (GH), mamotropima (PRL) i kortikotropima (ACTH). Sve ćelije su imunohistohemijski bojene i histološki analizirane, dok je za određivanje nivoa hormona u krvi korišćena ELISA metoda. Utvrđeno je da starenje prouzrokuje različite, uglavnom reduktivne promene volumena, broja i sekrecije hormon-produkujućih ćelija hipofize u našim animalnim modelima menopauze, izuzev na primeru PRL ćelija čiji je broj značajno povećan, a sekrecija intenzivirana. Posle tretmana ženki pacova srednjeg doba estradiolom apsolutna i relativna masa hipofize je značajno povećana u poređenju sa kontrolnim ženkama. Histološki parametri poput volumena ćelija i volumenske gustine PRL i ACTH ćelija su značajno povećani u poređenju sa kontrolnim vrednostima. Sa druge strane, pomenuti parametri u FSH, LH i GH, a u izvesnim slučajevima i TSH ćelijama su značajno smanjeni nakon tretmana estradiolom, u poređenju sa kontrolama. Koncentracije odgovarajućih hormona u krvi su pratile navedene promene histoloških parametara. Ova zapažanja ukazuju da estradiol davan menopauzalnim jedinkama ženskog pola može na specifičan način, dvosmerno, modifikovati histološke karakteristike i sekretornu aktivnost različitih hormon-produkujućih ćelija hipofize.Projekat ministarstva br. 17300

Pituitary Hyperplasia, Hormonal Changes and Prolactinoma Development in Males Exposed to Estrogens — An Insight From Translational Studies

Estrogen signaling plays an important role in pituitary development and function. In sensitive rat or mice strains of both sexes, estrogen treatments promote lactotropic cell proliferation and induce the formation of pituitary adenomas (dominantly prolactin or growth-hormone-secreting ones). In male patients receiving estrogen, treatment does not necessarily result in pituitary hyperplasia, hyperprolactinemia or adenoma development. In this review, we comprehensively analyze the mechanisms of estrogen action upon their application in male animal models comparing it with available data in human subjects. Sex-specific molecular targets of estrogen action in lactotropic (PRL) cells are highlighted in the context of their proliferative and secretory activity. In addition, putative effects of estradiol on the cellular/tumor microenvironment and the contribution of postnatal pituitary progenitor/stem cells and transdifferentiation processes to prolactinoma development have been analyzed. Finally, estrogen-induced morphological and hormone-secreting changes in pituitary thyrotropic (TSH) and adrenocorticotropic (ACTH) cells are discussed, as well as the putative role of the thyroid and/or glucocorticoid hormones in prolactinoma development, based on the current scarce literature

Positive effects of naringenin on near-surface membrane fluidity in human erythrocytes

Purpose: Deformability/rheologic behavior of erythrocytes are related to near-surface membrane fluidity. Specific agents can increase erythrocyte membrane fluidity in order to adjust hemodynamics in cardiovascular diseases. Grapefruit flavanone naringenin has been proposed for potential use in an alternative therapy of cardiovascular conditions. In respect to this, we assessed here effects of two nutritionally relevant concentrations of naringenin (0.1 and 1 μg/ml) on near-surface membrane fluidity in human erythrocytes. Methods: We used electron paramagnetic resonance spectroscopy and fatty acid spin probes (5-DS and 7-DS), the spectra of which are dependent on membrane fluidity. Results: The results showed a significant (p = 0.029) increase of membrane fluidity near the hydrophilic surface in erythrocytes treated with higher concentration of naringenin. In the deeper layer, just below the erythrocyte membrane phospholipid heads, both lower and higher concentration of naringenin significantly increased membrane fluidity (p = 0.036 and p = 0.028, respectively). Conclusions: These data document the positive and dose dependent effect of naringenin on near-surface membrane fluidity in human erythrocytes, recommending its use in the cardiovascular conditions characterized by disturbed hemodynamics

Old age-associated impairment of the rat liver antioxidant defense system: the basis for affirmation of the experimental model

Letter to the Edito

Vitex agnus-castus L.: Essential oil increases human erythrocyte membrane fluidity

Erythrocyte membrane fluidity is related to their rheologic behavior, the dynamic quality of erythrocytes, which is tempted in hypertension and atherosclerosis. An increased risk of these and other cardiovascular diseases occurs in ageing women. Menopause-related conditions are often treated with hormone replacement therapy that may increase the risk of malignancies. Vitex agnus-castus L. essential oil contains various organic compounds (monoterpenes, sesquiterpenes and terpenoids), and is increasingly used as an alternative therapy for menopausal symptoms. These components of the oil may be incorporated into cell membranes, thereby changing the membrane fluidity. The aim of this study was to determine the effects of Vitex agnuscastus essential oil on human erythrocyte membrane fluidity at graded depths. We used Electron Paramagnetic Resonance spectroscopy and fatty acid spin probes (5-doxyl stearic acid and 12-doxyl stearic acid), whose spectra depend on membrane fluidity. After treatment with Vitex agnus-castus essential oil the erythrocytes had a significant (p=0.029) and reversible increase in membrane fluidity in the deeper hydrophobic membrane regions, with no change (p>0.05) in fluidity near the membrane's hydrophilic surface. These results document increased fluidity of the human erythrocyte membrane by Vitex agnus-castus essential oil, and this action may be useful in patients with menopause-related hypertension and other cardiovascular conditions.Fluidnost membrane eritrocita uslovljava njihove reološke karakteristike, svojevrsne dinamičke kvalitete, izmenjene u hipertenziji i aterosklerozi. Rizik od navedenih i drugih kardiovaskularnih oboljenja se kod žena povećava sa starenjem. Tegobe koje prate menopauzu se obično ublažavaju supstitucionom hormonskom terapijom, koja može povećati rizik od pojave malignih oboljenja. Esencijalno ulje biljke Vitex agnus-castus L. sadrži različita organska jedinjenja (monoterpene, seskviterpene i terpenoide) i sve češće se koristi kao alternativno terapijsko sredstvo za simptome menopauze. Navedene komponente esencijalnog ulja mogu se ugraditi u ćelijske membrane i menjati njihovu fluidnost. Cilj studije bio je da se utvrde efekti esencijalnog ulja biljke Vitex agnus-castus na fluidnost membrane eritrocita po njenoj du bini. Korišćena je spektroskopija elektronske paramagnetne rezonance i masnokiselinske spinske probe (5-doksil stearinska i 12-doksil stearinska kiselina), čiji spektri za vise od fluidnosti membrane. Nakon tretmana eritrocita esencijalnim uljem biljke Vitex agnus-castus utvrđeno je značajno (p=0,029) i reverzibilno povećanje fluidnosti njihove membrane u dubljim, hidrofobnim regionima, dok u površinskim, hidrofilnim regionima eritrocitne membrane nisu utvrđene značajne promene (p>0,05). Ovi rezultati ukazuju na povećanje fluidnosti eritrocitne membrane nakon tretmana esencijalnim uljem biljke Vitex agnus-castus, što može biti koristan efekat pri tretmanu pacijentkinja sa hipertenzijom i drugim kardiovaskularnim oboljenjima u menopauzi.Projekat ministarstva br. 173009 i br. 17301

Effects of calcium administration on parathyroid gland, NaPi 2a cotransporter and PTH1R in an animal model of the andropause

Background: Increased risk of osteoporotic bone fractures represents the adverse event in andropausal men. Due to diminished calcium absorption in elderly, its supplementation is used for prevention and treatment of advanced-age osteoporosis. Methods: Sixteen-month-old Wistar rats were divided into sham-operated (SO), orchidectomized (Orx) and Ca2+treated orchidectomized (Orx+Ca) groups. Ca2+ (28.55 mg/kg b.w.) was administered intramuscularly for 3 weeks, while the SO and Orx received vehicle alone. Parathyroid glands (PTG) were analyzed histomorphometrically, while the expression of NaPi 2a mRNA from kidneys was determined by real time PCR. NaPi 2a and PTH1R abundance was detected immunofluorescently. Serum and urine parameters were determined biochemically. Results: The PTG volume was 15% (p<0.05) greater in Orx rats than in the SO group. In Orx+Ca2+ animals, PTG volume was decreased by 17% (p<0.05), when compared to the Orx rats. Orchidectomy led to an increment of serum PTH of 13% (p<0.05) compared to the SO group, while Orx+Ca decreased it by 10% (p<0.05) when compared to Orx animals. The intensity of the NaPi 2a signal was reduced in Orx rats, in comparison with the SO group. Orx+Ca2+ treatment increased the abundance of NaPi 2a, compared to the Orx group. In Orx rats, the staining for PTH1R was stronger when compared to the SO group, while the Orx+Ca2+ treatment induced reduction of the PTH1R immunofluorescence, compared to Orx animals. Orchidectomy increased Pi urinary concentrations by 8% (p<0.05), in comparison with the SO control, while in the Orx+Ca2+ group urinary Pi concentration was 5% lower (p<0.05) than for the Orx rats. Conclusions: Our results indicate that Ca2+ administration reduces the PTH serum level and the presence of PTH1R, while increased abundance of NaPi 2a cotransporter positively regulates Pi urine reabsorption in an animal model of the andropause.Uvod: Povećan rizik od preloma kostiju, izazvan osteoporozom, uobičajen je u andropauzi. Usled smanjene apsorpcije kalcijuma kod starijih osoba, on se često koristi u prevenciji i tretmanu osteoporoze u poznom dobu. Metode: Wistar pacovi stari 16 meseci podeljeni su na lažno operisanu (SO), orhidektomisanu (Orx) i Ca2+ tretiranu orhidektomisanu (Orx+Ca) grupu. Ca2+ je aplikovan intramuskularno u dozi od 28,55 mg/kg telesne mase, dok su kontrolne grupe SO i Orx primile odgovarajući volumen rastvarača. Paratireoidne žlezde (PTŽ) analizirane su histomorfometrijski, dok je nivo ekspresije gena za NaPi 2a određen pomoću PCR metode u realnom vremenu. Prisustvo NaPi 2a i PTH1R identifikovano je imunofluorescentnom metodom. Parametri iz seruma i urina određeni su biohemijskim metodama. Rezultati: Volumen PTŽ je povećan za 15% (p<0,05) kod Orx pacova u odnosu na SO grupu. Kod Orx+Ca tretiranih životinja, volumen PTŽ je smanjen za 17% (p<0,05) u poređenju sa Orx pacovima. Orhidektomija je povecala nivo PTH u serumu za 13% (p<0,05) u odnosu na SO grupu, dok je nivo ovog hormona kod Orx+Ca pacova smanjen za 10% (p<0,05) u poređenju sa Orx životinjama. Intenzitet NaPi 2a signala je redukovan kod Orx životinja u odnosu na SO grupu, dok Orx+Ca tretman povecava prisustvo NaPi 2a, u poređenju sa Orx grupom. Kod Orx pacova, obojenost PTH1R je jača u odnosu na SO grupu, dok je Orx+Ca tretman redukovao imunofluorescencu u poređenju sa Orx životinjama. Orhidektomija je povećala koncentraciju Pi u urinu za 8% (p<0,05) u poređenju sa SO kontrolom, dok je Orx+Ca tretman smanjio koncentraciju Pi u urinu za 5% (p<0,05) u odnosu na koncentraciju kod Orx pacova. Zaključak: Prikazani rezultati ukazuju na to da tretman Ca2+ smanjuje nivo PTH u serumu kao i prisustvo PTH1R, dok je zastupljenost NaPi 2a kotransportera povećana, što pozitivno reguliše reapsorpciju Pi iz urina u animalnom modelu andropauze.Projekat ministarstva br. 17300

The effect of SRIH-14 or octreotide on the morphological characteristics of adrenal medulla using newcast

The effects of chronic treatments with either SRIH-14 or octreotide on the adrenal medulla of male Wistar rats were examined. Adult males received subcutaneous (s.c.) injections of 20 μg/100 g body weight of either SRIH-14 or octreotide twice a day for 28 consecutive days. The absolute weights and the absolute volumes of the adrenal glands significantly (p<0.05) decreased after either treatment. The adrenal medulla was analyzed by histological and stereological methods using newCAST. Compared to the control, the relative volumes of the vascular tissues significantly (p < 0.05) decreased - by 40% and 25% in the SRIH-14- and octreotide-treated groups, respectively. In the SRIH-14- and octreotide-treated groups the relative volumes of chromaffin and interstitial tissue increased by 6% and 5% (p < 0.05), respectively. These findings show that both SRIH-14 and octreotide affect the morphological characteristics of the adrenal zona medullaris in a similar manner.Projekat ministarstva br. 143007

Effects of SRIH-14 on ACTH cells in male rats

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Estradiol and GH cells: Immunohistomorphometric study in an animal model of andropause

Andropause, the culminating phase of ageing in males is characterized by the decline of the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis that is responsible for somatic development. Estrogens on the other hand, assume a relevant somatic role, as well as the one in the pituitary. They are particularly interesting because of their therapeutic uses in certain common ageing-associated diseases. The aim of the present study was to examine the effects of subcutaneous treatment with estradiol, dipropionate on the immunohistomorphometric features of GH cells, in an animal model of the andropause. Sixteen-month-old Wistar rats were divided into sham-operated (SO), orchidectomized (Orx) and estradiol dipropionate-treated orchidectomized (Orx+Edp) groups. Estradiol dipropionate (0.625 mg/kg/day) was administered subcutaneously for three weeks while the SO and Orx groups received the vehicle alone. GH cells were identified by the peroxidase-antiperoxidase (PAP) immunohistochemical procedure. In the Orx+Edp group, GH cell volumes as well as the relative volume densities were significantly (p<0.05) decreased, by 27.4% and by 61.1%, respectively, in comparison with the same parameters of SO animals. Compared to the Orx animals, the cell volumes and relative volume densities of GH cells in Orx+Edp group were also significantly (p<0.05) decreased, by 23.2% and by 64.1%, respectively. It can be concluded that chronic estradiol dipropionate application in an animal in the andropause results in the suppression of immunohistochemical and morphometric parameters of pituitary GH cells.Projekat ministarstva br.17300