scholarly journals Inter-annual stability and age-dependent changes in plasma testosterone levels in a longitudinally monitored free-living passerine bird

2020 ◽  
Author(s):  
Martin Tešický ◽  
Tereza Krajzingrová ◽  
Jiří Eliáš ◽  
Hana Velová ◽  
Jana Svobodová ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Hormonal Regulation ◽  
Parus Major ◽  
Passerine Bird ◽  
Plasma Testosterone ◽  
Free Living ◽  
Testosterone Levels ◽  
Long Term Stability ◽  
Age Related ◽  
Age Dependent

AbstractWhile seasonal trends in the testosterone-driven hormonal regulation of resource allocation are known from cohort population samples, data on the inter-annual individual stability of blood plasma testosterone levels in wild birds are lacking, and our understanding of age-dependent changes is limited. We assessed plasma testosterone levels in 105 samples originating from 49 repeatedly captured free-living great tits (Parus major) to investigate their relative long-term stability and lifetime changes. Furthermore, we examined the inter-annual stability of selected condition-related traits (carotenoid- and melanin-based plumage ornamentation, ptilochronological feather growth rate, body mass, and haematological heterophil/lymphocyte ratio) and their relationships to testosterone levels. We show that testosterone levels in both sexes are inter-annually repeatable, both in their absolute values and individual ranks (indicating the maintenance of relative status in a population), yet with higher stability in females. Despite this stability, in males we found a quadratic dependence of testosterone levels on age, with a peak in midlife. In contrast, female testosterone levels showed no lifetime trend. The inter-annual stability of condition-related traits was mostly moderate and unrelated to plasma testosterone concentrations. However, males with elevated testosterone had significantly higher carotenoid-pigmented yellow plumage brightness, presumably serving as a sexually selected trait. Showing inter-annual stability in testosterone levels, this research opens the way to further understanding of the causes of variation in fitness-related traits. Based on a unique longitudinal dataset, this study demonstrates that male plasma testosterone undergoes age-related changes that may regulate resource allocation. Our results thus demonstrate that male birds undergo hormonal senescence similar to mammals.

Inter-annual repeatability and age-dependent changes in plasma testosterone levels in a longitudinally monitored free-living passerine bird

Oecologia ◽  
2021 ◽  
Author(s):  
Martin Těšický ◽  
Tereza Krajzingrová ◽  
Jiří Eliáš ◽  
Hana Velová ◽  
Jana Svobodová ◽  
...  
Keyword(s):  
Passerine Bird ◽  
Plasma Testosterone ◽  
Free Living ◽  
Testosterone Levels ◽  
Age Dependent

scholarly journals The serotonin transporter gene and female personality variation in a free-living passerine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bert Thys ◽  
Andrea S. Grunst ◽  
Nicky Staes ◽  
Rianne Pinxten ◽  
Marcel Eens ◽  
...  
Keyword(s):  
Serotonin Transporter ◽  
Strong Support ◽  
Serotonin Transporter Gene ◽  
Female Aggression ◽  
Nucleotide Polymorphisms ◽  
Transporter Gene ◽  
Evolutionary Potential ◽  
Free Living ◽  
Age Related ◽  
Age Dependent

AbstractQuantifying variation in behaviour-related genes provides insight into the evolutionary potential of repeatable among-individual variation in behaviour (i.e. personality). Yet, individuals typically also plastically adjust their behaviour in response to environmental conditions and/or age, thereby complicating the detection of genotype–phenotype associations. Here, using a population of free-living great tits (Parus major), we assessed the association between single nucleotide polymorphisms (SNPs) in the serotonin transporter gene (SERT) and two repeatable behavioural traits, i.e. female-female aggression and female hissing behaviour. For female-female aggression, a trait showing age-related plasticity, we found no evidence for associations with SERT SNPs, even when assessing potential age-dependent effects of SERT genotype on aggression. We also found no strong support for associations between SERT SNPs and hissing behaviour, yet we identified two synonymous polymorphisms (exon 13 SNP66 and exon 12 SNP144) of particular interest, each explaining about 1.3% of the total variation in hissing behaviour. Overall, our results contribute to the general understanding of the biological underpinning of complex behavioural traits and will facilitate further (meta-analytic) research on behaviour-related genes. Moreover, we emphasize that future molecular genetic studies should consider age-dependent genotype–phenotype associations for behavioural trait (co)variation, as this will vastly improve our understanding of the proximate causes and ultimate consequences of personality variation in natural populations.

scholarly journals Age-Related Alterations in Pituitary and Testicular Functions in Long-Lived Growth Hormone Receptor Gene-Disrupted Mice

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 6019-6025 ◽  
Author(s):  
Varadaraj Chandrashekar ◽  
Christina R. Dawson ◽  
Eric R. Martin ◽  
Juliana S. Rocha ◽  
Andrzej Bartke ◽  
...  
Keyword(s):  
Growth Hormone Receptor ◽  
Receptor Gene ◽  
Delayed Puberty ◽  
Plasma Testosterone ◽  
Mrna Levels ◽  
Testosterone Levels ◽  
Gh Receptor ◽  
Age Related ◽  
Igf I ◽  
Plasma Prl

The somatotropic axis, GH, and IGF-I interact with the hypothalamic-pituitary-gonadal axis in health and disease. GH-resistant GH receptor-disrupted knockout (GHRKO) male mice are fertile but exhibit delayed puberty and decreases in plasma FSH levels, testicular content of LH, and prolactin (PRL) receptors, whereas PRL levels are elevated. Because the lifespan of GHRKO mice is much greater than the lifespan of their normal siblings, it was of interest to compare age-related changes in the hypothalamic-pituitary-gonadal axis in GHRKO and normal animals. Plasma IGF-I, insulin, PRL, LH, FSH, androstenedione and testosterone levels, and acute responses to GnRH and LH were measured in young (2–4 and 5–6 months of age) and old (18–19 and 23–26 months of age) male GHRKO mice and their normal siblings. Plasma IGF-I was not detectable in GHRKO mice. Plasma PRL levels increased with age in normal mice but declined in GHRKO males, and did not differ in old GHRKO and normal animals. Plasma LH responses to acute GnRH stimulation were attenuated in GHRKO mice but increased with age only in normal mice. Plasma FSH levels were decreased in GHRKO mice regardless of age. Plasma testosterone responses to LH stimulation were attenuated in old mice regardless of genotype, whereas plasma androstenedione responses were reduced with age only in GHRKO mice. Testicular IGF-I mRNA levels were normal in young and increased in old GHRKO mice, whereas testicular concentrations and total IGF-I levels were decreased in these animals. These findings indicate that GH resistance due to targeted disruption of the GH receptor gene in mice leads to suppression of testicular IGF-I levels, and modifies the effects of aging on plasma PRL levels and responses of the pituitary and testes to GnRH and LH stimulation. Plasma testosterone levels declined during aging in normal but not in GHRKO mice, and the age-related increase in the LH responses to exogenous GnRH was absent in GHRKO mice, perhaps reflecting a delay of aging in these remarkably long-lived animals.

scholarly journals Drd4 gene polymorphisms are associated with personality variation in a passerine bird

2007 ◽  
Vol 274 (1619) ◽  
pp. 1685-1691 ◽  
Author(s):  
Andrew E Fidler ◽  
Kees van Oers ◽  
Piet J Drent ◽  
Sylvia Kuhn ◽  
Jakob C Mueller ◽  
...  
Keyword(s):  
Transcription Initiation ◽  
Gene Polymorphisms ◽  
Parus Major ◽  
Passerine Bird ◽  
Initiation Site ◽  
Novelty Seeking ◽  
Coding Region ◽  
Free Living ◽  
Single Nucleotide ◽  
Genetic Epistasis

Polymorphisms in several neurotransmitter-associated genes have been associated with variation in human personality traits. Among the more promising of such associations is that between the human dopamine receptor D4 gene ( Drd4 ) variants and novelty-seeking behaviour. However, genetic epistasis, genotype–environment interactions and confounding environmental factors all act to obscure genotype–personality relationships. Such problems can be addressed by measuring personality under standardized conditions and by selection experiments, with both approaches only feasible with non-human animals. Looking for similar Drd4 genotype–personality associations in a free-living bird, the great tit ( Parus major ), we detected 73 polymorphisms (66 SNPs, 7 indels) in the P. major Drd4 orthologue. Two of the P. major Drd4 gene polymorphisms were investigated for evidence of association with novelty-seeking behaviour: a coding region synonymous single nucleotide polymorphism (SNP830) and a 15 bp indel (ID15) located 5′ to the putative transcription initiation site. Frequencies of the three Drd4 SNP830 genotypes, but not the ID15 genotypes, differed significantly between two P. major lines selected over four generations for divergent levels of ‘early exploratory behaviour’ (EEB). Strong corroborating evidence for the significance of this finding comes from the analysis of free-living, unselected birds where we found a significant association between SNP830 genotypes and differing mean EEB levels. These findings suggest that an association between Drd4 gene polymorphisms and animal personality variation predates the divergence of the avian and mammalian lineages. Furthermore, this work heralds the possibility of following microevolutionary changes in frequencies of behaviourally relevant Drd4 polymorphisms within populations where natural selection acts differentially on different personality types.

Seasonal and Age-Related Changes in Plasma Testosterone Levels in Mountain White-Crowned Sparrows

The Condor ◽  
1990 ◽  
Vol 92 (1) ◽  
pp. 166-173 ◽  
Author(s):  
Martin L. Morton ◽  
Linda E. Peterson ◽  
Douglas M. Burns ◽  
Noella Allan
Keyword(s):  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Age Related ◽  
Age Related Changes

scholarly journals Neuroendocrine patterns underlying seasonal song and year-round territoriality in male black redstarts

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Camila P. Villavicencio ◽  
Harriet Windley ◽  
Pietro B. D’Amelio ◽  
Manfred Gahr ◽  
Wolfgang Goymann ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Life Cycle ◽  
Receptor Expression ◽  
Territorial Behavior ◽  
Plasma Testosterone ◽  
Estrogen Receptor Expression ◽  
Free Living ◽  
Testosterone Levels ◽  
Life Cycle Stages ◽  
Song Control

Abstract Background The connection between testosterone and territoriality in free-living songbirds has been well studied in a reproductive context, but less so outside the breeding season. To assess the effects of seasonal androgenic action on territorial behavior, we analyzed vocal and non-vocal territorial behavior in response to simulated territorial intrusions (STIs) during three life-cycle stages in free-living male black redstarts: breeding, molt and nonbreeding. Concurrently, we measured changes in circulating testosterone levels, as well as the mRNA expression of androgen and estrogen receptors and aromatase in the preoptic, hypothalamic and song control brain areas that are associated with social and vocal behaviors. Results Territorial behavior and estrogen receptor expression in hypothalamic areas did not differ between stages. But plasma testosterone was higher during breeding than during the other stages, similar to androgen receptor and aromatase expression in the preoptic area. The expression of androgen receptors in the song control nucleus HVC was lower during molt when birds do not sing or sing rarely, but similar between the breeding and the nonbreeding stage. Nevertheless, some song spectral features and the song repertoire differed between breeding and nonbreeding. Territorial behavior and song rate correlated with the expression of steroid receptors in hypothalamic areas, and in the song control nucleus lMAN. Conclusions Our results demonstrate seasonal modulation of song, circulating testosterone levels, and brain sensitivity to androgens, but a year-round persistency of territorial behavior and estrogen receptor expression in all life-cycle stages. This suggests that seasonal variations in circulating testosterone concentrations and brain sensitivity to androgens is widely uncoupled from territorial behavior and song activity but might still affect song pattern. Our study contributes to the understanding of the complex comparative neuroendocrinology of song birds in the wild.

PLASMA TESTOSTERONE AND ACCESSORY SEX GLANDS IN NORMAL AND CRYPTORCHID RATS

1972 ◽  
Vol 54 (2) ◽  
pp. 285-296 ◽  
Author(s):  
B. J. LLOYD
Keyword(s):  
Prostate Gland ◽  
Seminal Vesicles ◽  
Ventral Prostate ◽  
Plasma Testosterone ◽  
Progressive Decline ◽  
Testosterone Levels ◽  
Accessory Sex Glands ◽  
Gland Weight ◽  
Age Related ◽  
Fischer Rats

SUMMARY Plasma testosterone concentration and the weights of the seminal vesicles and ventral prostate gland were measured in normal and cryptorchid Fischer rats at 3, 4·5, 7·5 and 13·5 months of age, and in normal parabionts and cryptorchid parabionts of 13·5 months of age. Testosterone was measured individually by a protein-binding method. In normal rats, all parameters rose to a maximum at 7·5 months of age, then levelled off or declined at 13·5 months of age. In cryptorchid rats, a similar pattern at a lower level was found for accessory sex gland weight, but plasma testosterone levels showed a progressive decline from an above normal level at 3 months to a subnormal level at 13·5 months of age. Cryptorchid parabionts were less responsive to gonadotrophin stimulation from union with a castrated partner than normal parabionts. The present study showed that plasma testosterone levels in normal and cryptorchid rats are age-related. It also showed that the pattern of plasma testosterone levels observed in cryptorchid rats is different from that seen in normal rats. Accessory sex gland weight is also age-related but is not a reliable index of plasma testosterone levels.

Age-related changes in body weight, scrotal size and plasma testosterone levels in buffalo bulls ()

1984 ◽  
Vol 22 (6) ◽  
pp. 651-656 ◽  
Author(s):  
Manzoor Ahmad ◽  
M. Latif ◽  
Masood Ahmad ◽  
M.H. Qazi ◽  
N. Sahir ◽  
...  
Keyword(s):  
Body Weight ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Age Related ◽  
Age Related Changes

RELATIONSHIP BETWEEN PLASMA TESTOSTERONE LEVELS AND RISK FACTORS IN MALE PATIENTS WITH TYPE 2 DIABETES

2013 ◽  
pp. 57-63
Author(s):  
Thi Bach Oanh Nguyen ◽  
Hai Thuy Nguyen ◽  
Cuu Loi Nguyen
Keyword(s):  
Risk Factors ◽  
Blood Pressure ◽  
Type 2 Diabetes ◽  
Plasma Testosterone ◽  
Diabetic Patients ◽  
Testosterone Levels ◽  
Age Related ◽  
Male Patients ◽  
Type 2 Diabetic

Background: Testosterone is vital hormone for men’s health and a keyplayer in glucose homeostasis, lipid metabolism, and cardiovascular pathology. Testosterone deficiency is associated with age, many chronic health conditions and other metabolic disorders. Objectives: Of this study to assess the concentration of plasma testosterone in male patients with type 2 diabetes, and evaluate the relationship between plasma testosterone levels and the assosiated risk factors. Methods: 54 male patients with type 2 diabetes and 31 non diabetes subjects over 45 years old, were assessed plasma tetosterone and lipidemia concentration and risk factore including age, BMI, waist circumference, blood pressure. Results: The concentration of plasma testosterone in type 2 diabetic male patients was lower than that in normal male subjects (4.5± 1.59 vs 5.27± 1.59 ng/ml, p< 0.05). There was significantly difference of plasma tetosterone levels between diabetic patients and controls of < 60 ages and ≥ 60 ages were respectively (4.07± 1.19 vs 5.36± 1.89 ng/ml) and (4.76± 1.76 vs 5.22 ±1.39 ng/ml, p <0.05). There was correlation between plasma testosterone levels with WC (r = - 0.4242, p< 0.01) and BMI (r = -0.37, p<0.01) and no relationship significatively between plasma testosterone concentration with blood pressure and lipidemia in diabetic patients. Conclusions: Concentration of plasma testosterone in type 2 diabetic male patients was lower than that in healthy subjects of similar age, related with age, VB and BMI. Key words: Testosterone, diabetes, risk factors.

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