Introduction: Sexual hormone-binding globulin (SHBG) is a protein that binds to androgens and oestrogens, especially testosterone. The fraction of testosterone that is not bound to SHBG is the biologically active fraction which makes its determination more relevant than determining the total amount of circulating testosterone. It is difficult to measure the plasma concentration of free testosterone; therefore calculations using the concentrations of testosterone and SHBG are used to estimate the amount of free testosterone. A few calculations include the concentration of albumin because testosterone also binds to albumin. The main aims of this study were to verify a method for the determination of SHBG and to calculate a reference interval for free androgen index (FAI, testosterone/SHBG) in women. Other calculations for determination of the free testosterone fraction were compared. Methods: Testosterone, SHBG and albumin were measured in serum from 20 men and 100 women. Testosterone and SHBG was measured using immunoassays on a Roche Modular E instrument (ECLIA). Albumin was measured with a c8000 Architect instrument. Four calculations, two with only testosterone and SHBG and two with testosterone, SHBG and albumin were compared.  Results/Conclusion: The verification of the SHBG method was successful which means that the method can be taken into routine use. A reference interval for FAI was constructed. It was difficult to show if other estimation of free testosterone would work better than FAI in clinical practice. This is discussed.

Weltweit ist eine rasante Zunahme des Artensterbens auch bei der Klasse Aves zu verzeichnen. Durch Umweltveränderungen und unzählige andere menschliche Einflüsse (z.B. illegaler Handel) ist fast ein Drittel der Papageienpopulation (Psittaciformes) vom Aussterben bedroht. Eine Möglichkeit, diesen Trend aufzuhalten, besteht in der gezielten und effektiven Nachzucht bedrohter Arten in der Obhut von Menschen mit dem Ziel der späteren Wiederauswilderung. Leider waren bisher solche Bemühungen oft erfolglos. Dies ist der Tatsache geschuldet, dass fundierte wissenschaftliche Untersuchungen zum Reproduktionsstatus nahezu fehlen und ein Transfer der hormonanalytischen Methoden vom Säugetier zum Vogel nicht so einfach möglich ist. Ziel der vorliegenden Arbeit war die Etablierung von Methoden zur Hormonbestimmung in verschiedenen Medien beim männlichen Papagei, mit deren Hilfe eine Einordnung des Reproduktionsstatus möglich ist. Im Vordergrund standen dabei vor allem nicht-invasive Techniken, die mit deutlich geringerem Stress für die Tiere verbunden sind. Als Vertreter für die Gruppe der Papageienartigen wurden Wellensittiche (Melopsittacus undulatus, n=11), Nymphensittiche (Nymphicus hollandicus, n=9) und Halsbandsittiche (Psittacula krameri, n=7) ausgewählt und endokrinologisch untersucht. Diese Vögel wurden vom Bundesverband für fachgerechten Natur- und Artenschutz e.V. (BNA) zur Verfügung gestellt. Die Hormonanalyse erfolgte in den regelmäßig gesammelten Blut-, Speichel- und Kotproben der männlichen Psittaziden. Neben dem Sexualhormon Testosteron wurden die Blutspiegel des Stresshormons Corticosteron bestimmt, da eine mögliche Beziehung zwischen Stress und Testosteronsekretion besteht. In den Vorversuchen wurden zunächst geeignete Methoden für die Hormonanalyse in den verschiedenen Medien beim Papagei entwickelt. Zur Extraktion von Testosteron aus den Blut- und Kotproben erwies sich Diethylether als gut geeignet, während Speichel direkt ohne Extraktion im Testosteron-Enzymimmunoassay eingesetzt wurde. Da Papageien hauptsächlich primär konjugierte Testosteronmetabolite (85%) ausscheiden, wurden die Kotproben nach dem Trocknen und Einwiegen mit Hilfe der β-Glucuronidase/Arylsulfatase hydrolysiert und dann mit Diethyether extrahiert. Die Corticosteronanalyse im Plasma der Papageien erfolgte durch Fällung der Proteine mittels absolutem Alkohol und Einsatz der Plasmaextrakte in den Radioimmunoassay. Bei den verschiedenen Papageienspezies traten während der Untersuchungsperiode vergleichbare Plasma-Testosteronkonzentrationen auf. Die höchsten Plasmaspiegel (0,36 ng/ml) wiesen die Wellensittiche im März 2007 auf, ähnliche Konzentrationen (0,34 ng/ml) erreichten die Nymphensittiche im Februar 2007. Demgegenüber zeigten die Halsbandsittiche geringere maximale Konzentrationen (0,26 ng/ml) im November 2007. Im Kot der Papageien wurden erwartungsgemäß deutlich höhere Testosteronwerte gemessen, weil die Steroidausscheidung im Kot kumulativ eine zurückliegende Zeitperiode und Blut den aktuellen Hormonstatus zum Zeitpunkt der Probennahme widerspiegelt. Bezüglich der Haltungs- und Umweltbedingungen zeigten die Papageien maximale Testosteronspiegel während der kalten Jahreszeit, bei kurzer (Halsbandsittich) bzw. zunehmender Tageslichtlänge (Wellen- und Nymphensittich) und Haltung in der Innenvoliere. Dabei spielte die Niederschlagsmenge in der gemäßigten Klimazone offenbar weniger eine Rolle in der aviären Reproduktion. Die Verlaufsuntersuchungen des Stresshormons Corticosteron im Blut der Papageien ergaben speziesspezifische Unterschiede hinsichtlich der Konzentrationen, zeitlichen Verläufe und in Bezug zum Testosteronspiegel. Auffällig hohe Corticosteronkonzentrationen zeigten die nicht domestizierten Halsbandsittiche (15,9 – 35,6 ng/ml) im Vergleich zu den Wellensittichen (1,76 – 17,1 ng/ml) und Nymphensittichen (4,06 – 12,1 ng/ml), bei denen sich vermutlich im Laufe der Domestikation eine verminderte Sensibilität der HPA-Achse ausgebildet hat. In Bezug zum Plasma-Testosteronspiegel war bei den Wellen- und Halsbandsittichen ein gegenläufiger Zusammenhang erkennbar, wobei beim Nymphensittich eine positive Korrelation zwischen der Testosteron- und Corticosteronkonzentrationim Plasma bestand. Zusammenfassend lässt sich sagen, dass durch die Testosteronanalyse in Kot und Plasma eine Einordnung des Reproduktionsstatus beim Wellen-, Nymphen- und Halsbandsittich möglich ist. Es ist jedoch sinnvoll, Proben zu verschiedenen Zeitpunkten vergleichend zu betrachten, um die tierindividuellen Unterschiede zu berücksichtigen. Offensichtlich stehen die Steroidhormone der Gonaden und der Nebenniere zueinander in Beziehung, sodass auch Corticosteron in der Reproduktionsdiagnostik von männlichen Psittaziden Anwendung finden sollte.

Thesis (M.A.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : [109]-111).

Across three studies, the role that testosterone plays in how individuals respond psychologically, behaviorally, and physiologically to status challenges was investigated. Preliminary Studies 1 focused on how testosterone related to physiological and psychological responses to a medical threat. Preliminary 2 replicated the psychological effects observed in Preliminary Study 1. Study 3 examined how experimentally manipulated testosterone levels corresponded to responses to a socially judged physical endurance task across all three response types. Preliminary Study 1 examined the relationship between testosterone and conscious evaluations of and physiological reactions to a health threat. Participants were diagnosed with a fictitious enzyme deficiency before rating their views of the deficiency, as well as providing saliva samples before and after diagnosis. Basal testosterone was negatively associated with the belief that one actually had the deficiency, despite the diagnosis. Testosterone was also positively associated with a greater increase in salivary cortisol levels following the diagnosis. Self-reported anxiety was found to be positively associated with evaluating the deficiency as threatening. Preliminary Study 2 replicated the findings observed in Preliminary Study 1 regarding conscious evaluations of a medical threat. Using the same experimental manipulation, testosterone was again found to be negatively associated with ratings of the enzyme deficiency. In Preliminary Study 2, high levels of testosterone were associated with viewing the deficiency as less serious and viewing medical conditions, in general, as less threatening. Study 3 used a transdermal administration procedure to artificially elevate individuals’ testosterone levels before completing a socially evaluated task. Participants who received the testosterone administration showed greater physiological responses to the task, including cardiovascular responses and cortisol responses, compared to the placebo group. Unlike Preliminary Studies 1 and 2, Study 3 did not show any effect of testosterone on conscious evaluations of the task nor behavioral measures of performance. Taken together, the three studies highlight the different ways in which testosterone is related to responding to social threats. Testosterone appears to be associated with mobilizing physiological systems to theoretically facilitate behavioral responses to status threats. Testosterone also appears to be negatively associated with consciously evaluating certain types of threats. / text

The teleost ovarian follicle undergoes extensive remodeling and regression during the reproductive cycle—a process involving apoptosis and cell death. However, the hormonal regulation of these processes remains unclear. In the current study the role of testosterone in regulating regression of Atlantic croaker (Micropogonias undulatus) ovarian follicles was investigated in co-cultured granulosa/theca (G/T) cells. Testosterone (T) treatment enhanced serum starvation-induced cell death and apoptosis of G/T cells during the mature stage of oocyte maturation. This effect was mimicked by a cell-impermeable T conjugate, T-bovine serum albumin, indicating that this androgen action is initiated at the cell surface. Mibolerone, a nuclear androgen receptor agonist, was ineffective in promoting apoptosis and cell death, which suggests that T actions are independent from the nuclear receptor. Together, the data suggests that T-induction of apoptosis and cell death are through a novel membrane androgen receptor in the croaker ovary. T treatment also increased expression of a pro-apoptotic member of the Bcl-2 gene family, Bax, and two Bax upstream regulators, JNK and p53. These results suggest that T induces cell death of G/T cells in croaker through the apoptotic pathway involving JNK, p53 and Bax. An opposite response of cell death protection by T was also observed in G/T cells cultured from late-stage ovaries. This response was accompanied by a rapid increased ERK-1/-2 phosphorylation not seen in Mibolerone treatment. By examining the role of T in croaker follicle cell death and elucidating the corresponding basic mechanisms of androgen action, we are learning more about the regulatory components involved in the breakdown and remodeling stages of the teleost reproductive cycle. / text

Στην εργασία διερευνήθηκε πώς η έλλειψη του υποδοχέα της χαμηλής πυκνότητας λιποπρωτεϊνών (Ldlr-/-) τροποποιεί τις επιδράσεις της τεστοστερόνης στην παχυσαρκία και στις συναφείς μεταβολικές δυσλειτουργίες. ‘Εμμεση θερμιδομετρική ανάλυση έδειξε πως ο υπογοναδισμός σε μυς με έλλειψη του Ldlr συσχετίζεται με μείωση του βάρους του σώματος, και παράλληλα, αυξημένο μεταβολικό ρυθμό. Η έκφραση του κυτοχρώματος C και της UCP1 των μιτοχονδρίων ήταν αυξημένη στο λευκό λιπώδη ιστό, υποδεικνύοντας ότι η αυξημένη μεταβολική δραστηριότητα αντανακλά σε αυξημένο αριθμό μιτοχονδρίων με επίσης αυξημένη ικανότητα θερμογένεσης. Η αποκατάσταση της τεστοστερόνης σε ορχεκτομηθέντες μυς Ldlr-/- για διάστημα οχτώ εβδομάδων οδήγησε σε παχυσαρκία επαγόμενη από δίαιτα, υποδεικνύοντας την άμεση σχέση της τεστοστερόνης με τον παρατηρούμενο φαινότυπο. Η θεραπεία ψευδοχειρουργημένων μυών Ldlr-/- με εξεμεστάνη, έναν αναστολέα της αρωματάσης, για οχτώ εβδομάδες, έδειξε πως η αντίσταση στην παχυσαρκία των ορχεκτομηθέντων Ldlr-/- μυών είναι ανεξάρτητη από την δράση των οιστρογόνων. Συμπερασματικά, η εργασία δείχνει πως ο LDLr συσχετίζεται με μεταβολικές αλλαγές σε υπογοναδικούς μυς, οι οποίες δεν οφείλονται σε οιστρογονικές δράσεις, αλλά.στην ανεπάρκεια τεστοστερόνης. / In this work we investigated how low-density lipoprotein receptor deficiency (Ldlr-/-) modulates the effects of testosterone on obesity and related metabolic disorders. Indirect calorimetric analysis indicated that hypogonadism in Ldlr deficient mice correlates with a decrease in body weight and an increased metabolic rate. The expression of cytochrome C and UCP1 in mitochondria was increased in white adipose tissue, indicating that the increased metabolic activity reflects an increased number of mitochondria with an increased ability for thermogenesis. Testosterone replacement in orchectomized Ldlr-/- mice for a period of eight weeks led to diet induced obesity, suggesting a direct relationship between testosterone and the observed phenotype. Treatment of sham-operated Ldlr-/- mice with exemestane, an aromatase inhibitor, for eight weeks, showed that the obesity of orchectomized Ldlr-/- mice is independent of estrogen effects. In conclusion, this work demonstrates how the LDLr is associated with metabolic changes in hypogonadal mice which are not related to estrogenic effects but to testosterone deficiency.

Migration timing is a conserved life-history trait. To address the hypothesis that reproductive hormones are principal determinants of migration timing, I physiologically biopsied over 1000 sockeye salmon and monitored their subsequent behaviour with acoustic and radio telemetry as they migrated from the Pacific Ocean toward and into the Fraser River, and then onward to distant spawning areas. Links between physiology, behaviour, and survival were examined. Circulating testosterone was found to be positively correlated with the rates of river entry in Late-run females but not in males, despite having concentrations that were equal if not higher than those of females. The notion of protandrous migration, in which males synchronize their activities to the reproductive and migratory schedules of females, was postulated as the basis for this difference. Once in river however, successful males and females were those that (1) took longest to enter the river, and (2) had high somatic energy, low testosterone, and low gill Na+,K+-ATPase activities. An experimental test of the effect of reproductive hormones on the regulation of migration timing proved inconclusive. Relative to controls, GnRH and (or) testosterone treatment did not influence rates of ocean travel by males. Unfortunately, no females were examined. Nevertheless, significant, positive correlations between initial testosterone and travel times were found irrespective of hormonal treatment, which was unexpected but consistent with the previous studies. In an experimental simulation of an ‘early’ migration, normally timed Late-run sockeye exposed to typical 10 ºC river temperatures and then released to complete migration were 68% successful. In contrast, salmon held at 18 °C and released were half as successful. The expression of a kidney parasite was near maximal in the 18 °C fish and undetectable in the 10 °C fish. Only gill Na+,K+-ATPase activity differed between groups, with a drop in the 18 °C fish. Though no clear stress, reproductive, or energetic differences were observed between groups, the ultimate effect of high temperature treatment was high disease expression, slowed migration speeds, and high migration mortality. Changes in reproductive schedules, due to changes in latitudinal ocean distributions, are discussed as potential causes of early migration by Late-run sockeye.

Rapid increases in plasma androgens are generally associated with short-term aggressive challenges in many breeding vertebrates. However, some animals such as song sparrows (Melospiza melodia) are aggressive year-round, even during the non-breeding season, when gonads are regressed and systemic testosterone (T) levels are non-detectable. In contrast, levels of the prohormone dehydroepiandrosterone (DHEA) are elevated year-round in the plasma and brain. The local conversion of brain DHEA to potent androgens may be critical in regulating non-breeding aggression. 3β-hydroxysteroid dehydrogenase/Δ4-Δ5 isomerase (3β-HSD) catalyzes DHEA conversion to androstenedione (AE) and the cofactor NAD⁺ assists in this transformation. In this thesis, I asked whether brain 3β-HSD activity is regulated by social encounters in seasonally breeding male songbirds. In Experiment 1, I looked at the long-term seasonal regulation of brain 3β-HSD activity. 3β-HSD activity was highest in the non-breeding season compared to the breeding season and molt. In Experiment 2, I hypothesized that brain 3β-HSD activity is rapidly regulated by short-term social encounters during the non-breeding season. A 30 min social challenge increased aggressive behavior. Without exogenous NAD⁺, there was ~355% increase in 3β-HSD activity in the caudal telencephalon and ~615% increase in the medial central telencephalon compared to controls (p<0.05). With exogenous NAD⁺, there was no effect of social challenge on 3β-HSD activity. These data suggest that endogenous cofactors play a critical role in the neuroendocrine response to social challenges. The increase in brain DHEA conversion to AE during social challenges may be a mechanism to rapidly increase local androgens in the non-breeding season, when there are many costs of systemic T.

The mammalian kidney and reproductive systems both derive from a common embryological origin, the intermediate mesoderm. Abnormal intermediate mesoderm development can result in congenital abnormalities of the urogenital system, yet the molecular mechanisms that govern intermediate mesoderm development are incompletely defined. The spatial and temporal expression of the proteins BMP2 and 4 and their receptor ALK3, in urogenital tissue, suggests a function for BMP-ALK3 signaling in the intermediate mesoderm. It was found that Alk3IM null kidneys display renal hypoplasia, associated with a decrease in kidney size and nephron number. The phenotype of renal hypoplasia in Alk3IM nulls was associated with early decreased number of developing nephron structures and secondary defects in branching morphogenesis. While neither apoptosis nor cell proliferation differed in metanephric mesenchyme cells in Alk3IM nulls, markers of renal progenitor cells were decreased in mutant animals. It was observed that Alk3 expression in the intermediate mesoderm also controls mesonephric tubule number. Alk3IM nulls had fewer mesonephric tubules and fewer derivative Leydig cells. The reduction in Leydig cells resulted in decreased levels in serum testosterone and defects in seminal vesicle formation and fertility. Alk3 expression was also required for normal development of the corpus epididymis. The morphological defects in nephrogenesis were associated with decreased phospho-p38 MAPK expression and in the testis with decreased Phospho-SMAD1/5/8. These results elucidated a requirement for Alk3 signaling in controlling progenitor cells derived from the intermediate mesoderm.

1. INTRODUCTION 1.1. Work actuality In recent years the number of males with urination disorders mostly induced by prostate pathology has significantly increased [Gas et al., 1998; Khan, Khan et al., 2005; Amaral, Coeli et al., 2004]. Benign prostate hyperplasia (BPH) affects males at a much younger age making them complain of urination disorders of different types and intensity. It is quite a common pathology among males (which is) conditioned by life style and nutrition [Saga & Sugimura, 2004; Shabbir & Mumtaz, 2004; Cambell, 2005]. Clinical symptoms of BPH are not restricted only to urination complaints. With an increase of age of males, the balance of androgens and estrogens undergoes changes in the male organism, affecting the power of libido. According to C.M.Porth, 2005, two theories related to senility have been created, trying to explain biological processes occurring with age: The first theory is related to the so called genetically programmed changes. This theory affirms that changes brought on by aging, are genetically predetermined. Another theory is called the stochastic theory which says that all changes are of accidental nature, i.e. the body undergoes accidental changes. There is one more theory, the so-called neuroendocrinic theory of senility. This theory involves three basic factors of the process of aging: 1) facilitated degradation of hormones, 2) decreased synthesis and secretion of hormones, 3) diminished sensitivity of “target” receptors to... [to full text]