Factors in the dose-response effect of testosterone in the male ring dove☆ (original) (raw)
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Testosterone metabolism and testosterone-dependent characteristics in Japanese quail
Physiology & Behavior, 1984
In 2 independent experiments, we measured and correlated in maturing male Japanese quail the individual variations in sexual and aggressive behavior, cloacal gland size, testes weight, plasma testosterone concentrations and intraceilular testosterone metabolism by hypothalamus and cloacal gland. Cloacal gland area was only weakly related to plasma testosterone levels but was positively correlated with the production of active androgenic metabolites and negatively related to the producition of 5/3-reduced androgens (inactive) in the glandular tissue. Several measures of behavior were correlated with aspects of the testosterone metabolism in the anterior hypothalamus. In both experiments, the behavior of the birds was also strongly correlated with their testes weight and their cloacal gland area but weakly or not at all with their plasma testosterone levels. These studies suggest that testosterone metabolism is involved in the control of hormone action in maturing animals.
General and Comparative Endocrinology, 1983
Three experiments were carried out to study whether differences in the intracellular metabolism of testosterone (T) can explain sexually differential responses to T in Japanese quail. In the first experiment, a series of dose-response curves in which length of Silastic testosterone implants was related to effects on several behavioral and physiological variables was established. In Experiment 2, adult males and females were assigned to six experimental groups: intact males and females (I-males and I-females), castrated males and females implanted subcutaneously with 40-mm Silastic implants of T (T-males and T-females), and castrated males and females without hormone treatment (CX-males and CXfemales). No CX-bird (male or female) and no I-female exhibited male sexual behavior. However, I-males and T-males regularly copulated during the behavioral tests. No crowing was ever heard in CX-animals and I-females. T-females crowed less than T-males and their crowing sounded weaker than those of males. The cloaca1 glands of T-females were less deveioped than those of males. Radioimmunoassay of T and So-DHT showed that T-males and T-females have similar plasma levels of androgens. No striking differences were observed in the way testosterone is metabolized by the pituitary gland and central nervous tissues of males and females. By contrast, the production of 5a-dihydrotestosterone (5~ DHT) and 5a-androstane-3a, 17B-dio1&,3a-di01) was higher in the cloaca1 glands of males than in those of females. These sex differences were not detected between T-males and Tfemales. In experiment 3, the cloacal gland of males produced more Se-reduced metabolites than thase of females. The pituitary gland of females also produced more Sp-androstane-3cr,l7Bdiol (.5~,3adiol). In syringeal muscles, the production of SO-dihydrotestosterone (5B-DHT)and $3, 3~diol was higher in females compared to males.
Endogenous Testosterone Hormone and Agonistic Behavior in Male Japanese Quail (Coturnix japonica)
R ecently, Japanese quail (Coturnix japonica) has been used as a good laboratory model for poultry research due to their faster juvenile growth, higher egg production and shorter generation interval (Shit et al., 2010). The modern production systems and market demands mandate a reliance on the intensive farming system which guarantees high yield and minimizes the need for space and for labor. Nevertheless, this space restriction will inevitably lead to the appearance of abnormal behavioral patterns including pecking behavior which is one of the problems faced by poultry producers worldwide (Riber et al., 2007). Moreover, head injuries caused by aggressive pecking are an important welfare concern in quail farming when housed in the same place (Wechsler and Schmid, 1998). Aggressive pecking behavior in males, especially toward the head area, leads to several problems such as severe injuries (sometimes eye loss), cannibalism and even mortality which encompasses some economic concerns in quail farming (Mekawy, 2014). The previous findings have recognized testosterone hormone as the main regulator of inter-male aggression, particularly aggressive pecking behavior, among males of wild and domestic birds (Muller
Activating and organising effects of testosterone in black-headed gull chicks
dissertations.ub.rug.nl
Young of the black-headed gull (Larus ridibundus) frequently perform testosterone mediated aggressive behaviour. However, chicks temporarily exposed to testosterone show decreased growth rate and aberrant development. In earlier experiments we showed that the chicks deal with this problem by becoming less dependent in their aggression on high levels of testosterone in the course of ontogeny. This is caused by a testosterone induced long lasting increase in the sensitivity of the behaviour to short lasting elevations in the levels of testosterone. In this paper we analysed the activating and organising effects of testosterone in chicks of the black-headed gull in more detail. Chicks were placed in small peer groups by which testosterone production was suppressed. At three age classes (6, 12, 22 days after hatching) part of the birds received a silicon tube filled with testosterone propionate for 10 days. The other birds received an empty tube. Behaviour was measured in a standardised behavioural test. The activating effect of testosterone was independent of age and sex of the birds. Testosterone stimulated those patterns normally used in territorial defence, and no sexual displays, while begging for food decreased in frequency. In all three age classes, the aggressive behaviours stayed on a high level of performance after termination of hormonal treatment in comparison with the untreated birds. This long lasting effect of testosterone was temporary, and declined at the time of fledging at the age of 40 to 50 days. The possibility of adrenal testosterone production, and age-dependent effects of testosterone are discussed.
Behavioral evidence for sex steroids hypersensitivity in castrated male canaries
Hormones and behavior, 2018
In seasonally breeding songbirds such as canaries, singing behavior is predominantly under the control of testosterone and its metabolites. Short daylengths in the fall that break photorefractoriness are followed by increasing daylengths in spring that activate singing via both photoperiodic and hormonal mechanisms. However, we observed in a group of castrated male Fife fancy canaries maintained for a long duration under a short day photoperiod a large proportion of subjects that sang at high rates. This singing rate was not correlated with variation in the low circulating concentrations of testosterone. Treatment of these actively singing castrated male canaries with a combination of an aromatase inhibitor (ATD) and an androgen receptor blocker (flutamide) only marginally decreased this singing activity as compared to control untreated birds and did not affect various measures of song quality. The volumes of HVC and of the medial preoptic nucleus (POM) were also unaffected by these...
The effects of testosterone manipulation on the body condition of captive male yellow-legged gulls
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2002
Persistently high testosterone levels are believed to be costly to males due to their negative effect on body condition. However, this assumption could not be validated when we analysed birds isolated from all social interactions. The hypothesis was tested on birds kept in isolation in order to analyse the effects of testosterone per se, and thereby Ž . exclude the influence of social interactions. Adult male yellow-legged gulls Larus cachinnans were captured, and after a period of adjustment, some individuals were subcutaneously implanted with testosterone, while the rest were used as controls. The gulls received ad libitum food for 10 days and were then fasted for 4 days. Thyroid hormones, body-mass Ž . change, daily food intake, hematocrit and several plasma biochemical parameters were analysed. Treated T -males Ž . maintained constant levels of plasma total protein throughout the experiment, whilst control C -males showed a decrease. We did not find any other differences between groups for the other variables analysed. Since the implanted birds sustained high testosterone levels for a number of days, any cost to body condition would have been revealed if these costs levels were actually important. Our results do not support the hypothesis that a reduction in body condition can be directly produced by plasma testosterone, although total protein changes do suggest different anabolic patterns in testosterone-treated gulls. ᮊ
Sensitisation of social behaviour to testosterone in young black-headed gulls
dissertations.ub.rug.nl
In previous studies we found that in gull chicks temporary treatment with testosterone resulted in a long-lasting increase in responsiveness of aggressive behaviour to an aggressive challenge. Since these challenges induced a short lasting elevation in testosterone levels in both hormonally treated chicks and control chicks, it was hypothesised that the treatment increased the sensitivity to the hormone. The effect disappeared around day of fledging. In this paper we tested: (1) this sensitivity hypothesis, (2) whether the long-lasting effect is confined to an early sensitive period, or can be induced in juvenile gulls too, and (3) whether the effect can be extended to several months. Juvenile fledged gulls were temporarily treated with testosterone or sham operated at the age of 3.5 and 10 months. After cessation of testosterone treatment the birds still performed aggressive behaviour in higher frequencies than untreated controls, especially during a social challenge. Birds treated with testosterone at 3.5 months of age showed a much faster increase in aggressive behaviour during subsequent treatment at 10 months of age than birds treated for the first time at 10 months of age. It is concluded that in a wide range of ages temporary exposure to testosterone can induce a long-lasting increase in sensitivity of aggressive behaviour to testosterone. It has been found in several animal species, including adult birds, that a social challenge outside the breeding season, when basal testosterone levels are low, is related to a short lasting elevation in levels of this hormone that mediates the aggressive response to the challenge. Our results open the possibility that the sensitivity of the aggressive response to the challenge is influenced by the elevated basal testosterone levels during the beginning of the breeding season.