Browsing by Subject "Testosterone"
Now showing 1 - 7 of 7
Results Per Page
Sort Options
- PublicationOpen AccessComparison of testis structure, function and thyroid hormone levels in control C57BL/6 mice and anti-mullerian hormone over expressing mice(Murcia: F. Hernández, 2010) Chamindrani Mendis-Handagama, S.M.L.; Siril Ariyaratne, H.B.; Fecteau, Kellie A.; Grizzle, Judith M.; Jayasundera, Nilanthi K.Anti-Mullerian hormone (AMH) is considered as a negative regulator of postnatal Leydig cell (LC) differentiation, because AMH over expressing mice (Mt-hAMH mice) testes are deficient in LC. Therefore, in the present study Mt-hAMH mice was used as a model to examine the process of postnatal LC differentiation. Testis structure-function studies were performed in age-matching Mt-hAMH and C57BL/6 (controls) mice; testicular components were quantified and circulating testosterone and thyroid hormone levels (thyroxine/T4 and triiodothyronine/T3; necessary for postnatal LC differentiation) were determined. Results revealed that Mt-hAMH mice were heavier and their testis weights were smaller compared to controls. Mast cells were present in Mt-AMH testis interstitium, but absent in controls. The absolute volumes of seminiferous tubules (ST), testis interstitium, LC and blood vessels per testis were lower and lymphatic space was higher in Mt-hAMH mice than in controls (p<0.05). The average cell LC volume and their number per testis, ST length, plasma testosterone, luteinizing hormone-stimulated testosterone secretion per testis and per LC in vitro, plasma T4 and T3 were significantly lower in Mt-hAMH mice compared to controls (p<0.05). Increased body weight in Mt-hAMH mice could be attributed to the reduced T4 and T3. Reduced testis weight in Mt-AMH mice is explained by the reduced ST volume in them. Reduced plasma testosterone, testicular and LC testosterone secretion in vitro in Mt-hAMH mice can be explained by the reduced number, size and steroidogenic potential of LC in Mt-hAMH mice. Study revealed several structure-function deficiencies in Mt-AMH mouse compared to controls, which were not documented in previous investigations. As hypothyroidism causes arrest in postnatal LC differentiation, it is suggested that the reduced LC number in Mt-hAMH testes could be at least in part due to their reduced thyroid hormone levels. However, latter concept needs to be further tested in future investigations.
- PublicationOpen AccessEffect of estrogenization in the first day of life on the reproductive system in male rats(Murcia : F. Hernández, 1994) Limanowski, A.; Miskowiak, B.; Otulakowski, B.The aim of the present report was to investigate dynamics of morphological and functional changes in the reproductive system of male rats between 20th and 84th day of life, injected neonatally with a single dose of stilbestrol. Marked reduction in relative weights of testes and accessory sexual glands was demonstrated in various periods of life. This was associated with inhibition of spermatogenesis at the stage of primary spermatocytes and with morphological as well as functional alterations in epididymis? seminal vesicles and ventral prostate. In the serunl, high levels of LH and lowered testosterone levels were demonstrated.
- PublicationOpen AccessEffects of melatonin, testosterone and the two hormones administered in parallel on epididymis of the rat estrogenized with stilbestrol in the first day of life(Murcia : F. Hernández, 1996) Limanowski, A.; Miskowiak, B.; Otulakowski, B.Effect of melatonin, testosterone and of both hormones given in parallel on rat epididymis was tested in rats given a single dose of 1 mg stilbestrol on the first day of the life. The hormones were given daily for 39 days, beginning from the 20th or 28th day of life. The single dose of estrogen treatment resulted in epididymis atrophy, accompanied by changes in glandular epithelium and in its stroma, when the rats reached mature age (59 or 67 days of life). In such rats, LH gonadotropin level was elevated and testosterone level was decreased. Administration of melatonin failed to affect the changes induced by estrogen treatment. Administration of testosterone alone or of testosterone in parallel with melatonin caused the epididymis status to resemble more closely that seen in control animals. Efferent ductules of the testis (head of epididymis) were also demonstrated to be more sensitive to the performed experimental procedures than the duct of the epididymis (body and tail of the epididymis).
- PublicationOpen AccessEffects of photo stimulation and nonstimulation of golden hamsters (Mesocricetus auratus) from birth to early puberty on testes structure and function(Murcia : F. Hernández, 2009) Hance, Michael W.; Mason, J.Ian; Chamindrani Mendis-Handagama, S.M.L.We tested whether puberty in golden hamsters is photoperiodically controlled. Hamsters were raised under 14:10 hours Light:Dark (14L) and 1:23 hours Light:Dark (1L) respectively, from birth to 28 days and tested for various parameters. Body weight, Leydig cell (LC) size and testicular testosterone secretion were greater and plasma thyroxin (T4), testicular androstenedione secretion and LC number were lower (P<0.05) in 1L than 14L hamsters. Volumes of testicular components were similar in the two groups. 3ß-hydroxy steroid dehydrogenase immunohistochemistry demonstrated LC progenitors and newly formed adult LC (ALC) in 14L hamsters, which were absent in 1L hamsters; they contained only fetal LC (FLC). Latter findings suggest the presence and absence of postnatally-differerentiated LC in 14L and 1L hamsters, respectively. Androgen results agreed with these findings, because FLC primarily secrete testosterone, and androstenedione is a major androgen secreted by the newly formed ALC. Reduced T4 in 1L hamsters is attributed to the inhibition of thyroid function by the increased duration of melatonin secretion due to non-photostimulatory conditions. The arrest in LC differentiation in 1L hamsters is attributed to low T4 levels. Although the testis size is unaltered under nonphotostimulatory conditions, postnatal LC differentiation is inhibited in golden hamsters, and therefore, it is logical to suggest that their puberty is photoperiodically controlled.
- PublicationOpen AccessHistological parameters of the adrenal cortex after testosterone application in a rat model of the andropause(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Ajdžanović, Vladimir Z.; Jarić, Ivana M.; Živanović, Jasmina B.; Filipović, Branko R.; Šošić Jurjević, Branka T.; Ristić, Nataša M.; Stanković, Sanja D.Histological analysis of the adrenal cortex, after testosterone application in a rat model of the andropause, was the main subject of the present study. Middle-aged Wistar rats were divided into shamoperated (SO; n=8), orchidectomized (Orx; n=8) and testosterone treated orchidectomized (Orx+T; n=8) groups. Testosterone propionate (5 mg/kg b.m. /day) was administered for three weeks, while SO and Orx groups received the vehicle alone. Histological objectives were achieved using stereology, histochemistry and steroid receptor immunostaining. The concentrations of testosterone, aldosterone, corticosterone and DHEA were determined by immunoassays. Expectedly, increased (p<0.05) serum concentration of testosterone was observed in Orx+T group. The volume of ZG cells and nuclei increased in Orx+T animals by 50% and 25% (p<0.05) respectively, but the serum concentrations of aldosterone decreased (p<0.05) by 60%, all compared to the same parameters in Orx group. The immunostaining for androgen receptors (ARs) suggested their cytoplasmic localization in ZG cells of Orx+T rats. Volume of the ZF cell nuclei in Orx+T group decreased (p<0.05) by 17%, which was followed by the significant (p<0.05) fall in corticosterone production and secretion, all in comparison with Orx animals. Also, nuclear immunolocalization of ARs of high optical density was observed through the ZF of Orx+T group. In Orx+T rats volume of ZR cells and nuclei, and circulating DHEA concentration increased (p<0.05) by 68%, 22% and about 6.6 times respectively, compared to Orx animals. Besides the extra-receptor actions in adrenal cortex, testosterone supposedly affects some steroidogenesisrelated gene expression, as indicated by centripetal rise in the number of nuclear ARs.
- PublicationRestrictedSpecific and non-overlapping functions of testosterone and 11-ketotestosterone in the regulation of professional phagocyte responses in the teleost fish gilthead seabream(Elsevier, 2012-09-06) Águila Martínez, Sonia; Castillo Briceño, P.; Sánchez, M.; Cabas, Isabel; García Alcázar, Alicia; Meseguer, José; Mulero Méndez, Victoriano Francisco; García Ayala, Alfonsa; Biología Celular e Histología; ; MedicinaSex hormones, both estrogens and androgens, have a strong impact on immunity in mammals. In fish, the role of androgens in immunity has received little attention and contradictory conclusions have been obtained. However, it is well known that sex steroids are involved in fish growth, osmoregulation and gonad remodelation. In this study, we examine the in vitro effects of testosterone and 11-ketotestosterone, the two main fish androgens, on the professional phagocytes of the teleost fish gilthead seabream (Sparus aurata L.). Although both testosterone and 11-ketotestosterone failed to modulate the respiratory burst of seabream phagocytes, testosterone but not 11-ketotestosterone was able to increase the phagocytic ability of non-activated phagocytes. Curiously, 11-ketotestosterone was more powerful than testosterone at inducing the expression of its own receptor, namely androgen receptor b (ARb), in acidophilic granulocytes (AGs), but none of them affected the basal ARb expression levels in macrophages (MØ). Furthermore, although physiological concentrations of testosterone exerted a pro-inflammatory effect on both AGs and MØs, 11-ketotestosterone showed an anti-inflammatory effect in AGs and a strong pro-inflammatory effect in MØs. Interestingly, both androgens modulated the expression of toll-like receptors in these two immune cell types, suggesting that androgens might regulate the sensitivity of phagocytes to pathogens and damage signals. Testosterone and 11-ketotestosterone have a competitive effect, at least, on the modulation of the expression of some genes. Therefore, our results show for the first time a non-overlapping role for testosterone and 11-ketotestosterone in the regulation of professional phagocyte functions in fish.
- PublicationOpen AccessSteroid receptors in the testis: implications in the physiology of prenatal and postnatal development and translation to clinical application(Universidad de Murcia. Departamento de Biología Celular e Histología, 2023) Rey, Rodolfo A.The testes are the main source of sex steroids in the male, especially androgens and to a lesser extent estrogens. In target cells, steroid hormones typically signal after binding to intracellular receptors, which act as transcription factors. Androgens and estrogens have ubiquitous functions in peripheral organs, but also have paracrine actions within the gonads where they are far more concentrated. The levels of steroid production by the testes vary throughout fetal and postnatal development: they are high in intrauterine life and in the first months after birth, then they decline and are almost undetectable in childhood and increase again during puberty to attain adult levels. The expression of the androgen and estrogen receptors also depict specific ontogenies in the various testicular cell types. The combination of intratesticular steroid concentration with the pattern of expression of the steroid hormone receptors defines androgen and estrogen action on Sertoli, germ and Leydig cells. Here, we review the ontogeny of expression of the androgen and estrogen receptors in the testis, its impact on testicular physiology during prenatal and postnatal development, as well as its implication on the pathophysiology of different disorders affecting gonadal function throughout life.