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Hormonal control of male traits in leopard gecko, Eublepharis macularius
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Rehák, Ivan (referee)
It is generally believed that the presence of male traits is regulated by androgens. This thesis is designed to reveal the influence of testosterone on male traits in the leopard gecko, Eublepharis macularius. The noninvasive skin application mixture of vegetable oil and testosterone was used to manipulate the hormonal status of females and castrated males. This method has proven to be an effective alternative to the widely used hormonal implants. Manipulation was successfully validated, and there was apparent progressive increase of male sexual behavior in both groups. In females, the onset lasted much longer time, but both groups were able to perform all components of males sexual behaviour. Furthermore, I found that, contrary to widespread view, male sexual behavior persisted several weeks after reduction of testosterone levels in both manipulated groups. These results bring new evidence for temporary organization of male sexual behaviour by testosterone. Powered by TCPDF (www.tcpdf.org)
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Hormonal control of aggressive behaviour in lizards
Rauner, Petr ; Kratochvíl, Lukáš (advisor) ; Gregorovičová, Martina (referee)
Aggression is a highly functional form of social behaviour, which can be observed in nearly all species of vertebrates including lizards. There are many forms of aggressive behaviour and there is very significant difference in the physiological basis among them. The main and best understood hormone affecting aggression, is testosterone, but there exists evidence that some aggressive behaviour can be influenced by other hormones as well for example by progesterone, estradiol and corticosterone. The effect of these hormones on the organism is traditionally divided into the activation and organizational effects. Organizational effects are permanent and occur usually in the earlier stages of development. Activation effects are temporary and occur during the entire life. Elevated testosterone levels usually stimulate aggressive behaviour in both males and females. Progesterone and estradiol affect aggressive behaviour similarly but less effective. It is uncertain whether their effects are direct, or whether they are only a side-effect of testosterone, which is a precursor of estradiol and which has progesterone as own precursor. Corticosterone affects aggressive behaviour indirectly by influencing levels of testosterone. Hormonal influence on aggression in lizards is not the sole factor, but it depends on...
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Hormonal control of male sexual behaviour in reptiles
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Landová, Eva (referee)
The most important hormone affecting typical male sexual behavior in reptiles is testosterone, but also other steroid hormones such as dihydrotestosterone, estrogens or progestins may be involved in this regulation. According to the organizational-activational hypothesis testosterone acting during early ontogenic stage has an organizational effect on adult behavior and this behavior is triggered by influence of recent levels of hormones. Moreover, it was formulated the hypothesis on temporary organization of male sexual behvior that could change existing interpretations. Reptile reproductive strategies use to be classified according to gametogenesis and steroidogenesis as associated or dissociated reproductive strategies howerever, this division is rather artificial. This review summarizes existing knowledge of the hormonal influence of sexual behavior in reptiles, and comments the most common methods.
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Noninvasive measurement of steroid homones and effect of hormonal manipulation on behaviour in the gecko Paroedura picta
Matušková, Lucie ; Kratochvíl, Lukáš (advisor) ; Fraňková, Marcela (referee)
Hormones influence life of all animals. Not only they affect physiological changes in organisms, but also impact their behaviour. This work focuses at two main groups of steroid hormones: glucocorticoids and androgens. Glucocortiods are activated in response to stress. Their levels can be measured using non-invasive methods, which have a range of advantages. The main advantage is the feedback-free sample collection for enzyme immunoassay. As the measurement involves metabolites of the hormones rather than the hormones themselves, prior validation of the method is, however, necessary. This work reports on a study aiming to validate non-invasive measurement on the Madagascar Ground Gecko (Paroedura Picta). The validation was based on ACTH challenge test: Synacthen Depot was injected, which should lead to increased blood level of glucocorticoids. The validation, however, was not successful. The measurement did not discover significant increase in the levels of the metabolites of glucocorticoids. In addition, the work focuses on behavioural effects of testosterone, the primary androgen. Hormonal manipulations have been carried out on several male and female specimens. The results have discovered differences in sexual behaviour between control groups. On the other hand, the hormonal manipulations had no...
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Hormonal Aspects of Antler Growth Regulation
Kužmová, Erika ; Bartoš, Luděk (advisor) ; Petr, Jaroslav (referee) ; Kierdorf, Uwe (referee)
Hormonal aspects of antler growth regulation Erika Kužmová Abstract Deer antlers are the only mammalian organ that completely regenerates and therefore they became an object of rising interest as a potential model for bone growth and development. In recent years, it has been confirmed that annual regeneration of the antler is initiated from the stem cell niche localised in the pedicle periosteum. Antlers grow to the length at the tip. Only a little is known about endocrine stimulation of antler growth and some discrepancy has arisen between in vivo and in vitro studies over the decades. As the secondary sexual character, the antler cycle timing and growth are linked to seasonal levels of testosterone. Since the levels are at their minimum during the antler growth phase, according to many mainly in vitro studies, insulin-like growth factor-1 (IGF-1) tends to be accepted as the "antler stimulating hormone". Since the conclusion about the role of IGF-1 was contradictory to previous opinions and also in contrast with our own experience, we aimed to verify the role of IGF-1 in vitro. Our ex- periments were based on existing in vivo studies demonstrating the importance of testosterone, even in its low levels, and on the hypothesis that testosterone should be the "antler stimulating hormone". We performed in vitro...
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Natural bodybuilding as the adequate physical activity
BROŽEK, Pavel
The main topic of this thesis is natural bodybuilding as an adequate physical puff-vita, make a survey of the possibilities and pros natural bodybuilding. The research group was composed of twenty-one propanedinitrile, for which I have applied the appropriate physical activating sadness. Their output of the measurement will be used for options to choose natural bodybuilding as another alternative to a healthy lifestyle. Everything is subject to appropriate physical activity and proper diet and thus also other ways to maintain physical and mental health.
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