Browsing by Subject "Testosterone"

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  • Zöttl, Markus; Vullioud, Philippe; Goddard, Katy; Torrents-Ticó, Miquel; Gaynor, David; Bennett, Nigel C.; Clutton-Brock, Tim (2018)
    Abstract In Damaraland mole-rats (Fukomys damarensis), non-breeding subordinates contribute to the care of offspring born to the breeding pair in their group by carrying and retrieving young to the nest. In social mole-rats and some cooperative breeders, dominant females show unusually high testosterone levels and it has been suggested that high testosterone levels may increase reproductive and aggressive behavior and reduce investment in allo-parental and parental care, generating age and state-dependent variation in behavior. Here we show that, in Damaraland mole-rats, allo-parental care in males and females is unaffected by experimental increases in testosterone levels. Pup carrying decreases with age of the non-breeding helper while the change in social status from non-breeder to breeder has contrasting effects in the two sexes. Female breeders were more likely than female non-breeders to carry pups but male breeders were less likely to carry pups than male non-breeders, increasing the sex bias in parental care compared to allo-parental care. Our results indicate that testosterone is unlikely to be an important regulator of allo-parental care in mole-rats.
  • Eriksson, C. J. P.; Etelälahti, T. J.; Apter, S. J. (2017)
    A number of studies have shown that stress and an activated hypothalamic-pituitary-adrenal (HPA) axis are associated with increased voluntary alcohol drinking. Recently, associations have been found between activated HPA and hypothalamic-pituitary-gonadal (HPG) axes in alcohol-preferring AA and non-preferring ANA, F2 (crossbred second generation from original AA and ANA), and Wistar rats. The aim of the present study has been to determine the role of corticosterone and alcohol-related testosterone-effects in subsequent alcohol drinking in AA, ANA, F2 and Wistar rats. The present study comprises of four substudies presenting new analyses of existing data, by which correlations between basal corticosterone levels, changes in testosterone levels during alcohol intoxications and subsequent voluntary alcohol consumption are investigated. The results displayed positive correlations between basal corticosterone levels and subsequent alcohol-mediated testosterone elevations, which was positively associated with voluntary alcohol consumption. The results also showed a negative correlation between basal corticosterone levels and alcohol-mediated testosterone decreases, which was negatively associated with alcohol consumption. In conclusion, the present study displays novel results, according to which the HPA axis, one hand, relates to testosterone elevation (potentially causing and/or strengthening reinforcement) during alcohol intoxication, which in turn may relate to higher voluntary alcohol consumption (AA rats). Vice versa, the HPA axis may also relate to alcohol-mediated testosterone decrease (causing testosterone reduction and disinforcement) and low-alcohol drinking (ANA, F2 and Wistar rats). In addition, the present results showed that alcohol-mediated testosterone changes may also, independently of the HPA axis, correlate with voluntary alcohol drinking, which indicate the impact of genetic factors. Thus, the role of the HPA-axis may be more related to situational stress than to intrinsic factors. In further studies, it should be investigated, whether the present results also apply to stress and human alcohol drinking.
  • Karkkainen, Olli; Hakkinen, Merja R.; Auriola, Seppo; Kautiainen, Hannu; Tiihonen, Jari; Storvik, Markus (2016)
    Intra-tissue levels of steroid hormones (e.g., dehydroepiandrosterone [DHEA], pregnenolone [PREGN], and testosterone [T]) may influence the pathological changes seen in neurotransmitter systems of alcoholic brains. Our aim was to compare levels of these steroid hormones between the post-mortem brain samples of alcoholics and non-alcoholic controls. We studied steroid levels with quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) in post-mortem brain samples of alcoholics (N = 14) and non-alcoholic controls (N = 10). Significant differences were observed between study groups in DHEA and PREGN levels (p values 0.0056 and 0.019, respectively), but not in T levels. Differences between the study groups were most prominent in the nucleus accumbens (NAC), anterior cingulate cortex (ACC), and anterior insula (AINS). DHEA levels were increased in most alcoholic subjects compared to controls. However, only a subgroup of alcoholics showed increased PREGN levels. Negative Spearman correlations between tissue levels of PREGN and previous reports of [H-3]naloxone binding to mu-opioid receptors were observed in the AINS, ACC, NAC, and frontal cortex (R values between -0.6 and -.8; p values
  • Vihma, Veera; Naukkarinen, Jussi; Turpeinen, Ursula; Hämäläinen, Esa; Kaprio, Jaakko; Rissanen, Aila; Heinonen, Sini; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Mikkola, Tomi S.; Tikkanen, Matti J.; Pietiläinen, Kirsi H. (2017)
    Obesity and ageing are associated with lower serum testosterone levels in men. How fat distribution or adipose tissue metabolism, independent of genetic factors and age, are related to sex steroid metabolism is less clear. We studied the associations between adiposity and serum sex hormone concentrations, and mRNA expression of genes regulating sex hormone metabolism in adipose tissue in young adult male monozygotic (MZ) twin pairs. The subjects [n = 18 pairs; mean age, 32 years; individual body mass indexes (BMIs) 22-36 kg/m(2)] included 9 male MZ twin pairs discordant for BMI [infra-pair difference (Delta) in BMI >= 3 kg/m(2)]. Sex steroid concentrations were determined by liquid chromatography-tandem mass spectrometry, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and mRNA expressions from subcutaneous adipose tissue by Affymetrix. In BMI-discordant pairs (mean Delta BMI = 5.9 kg/m2), serum dihydrotestosterone (DHT) was lower [mean 1.9 (SD 0.7) vs. 2.4 (1.0) nmol/l, P = 0.040] and mRNA expressions of DHT-inactivating AKR1C2 (P = 0.021) and cortisol-producing HSD11B1 (P = 0.008) higher in the heavier compared to the leaner co-twins. Serum free 17 beta-estradiol (E2) was higher [2.3 (0.5) vs. 1.9 (0.5) pmol/l, P = 0.028], and in all twin pairs, serum E2 and estrone concentrations were higher in the heavier than in the leaner co-twins [107 (28) vs. 90 (22) pmol/l, P = 0.006; and 123 (43) vs. 105 (27) pmol/l, P = 0.025]. Within all twin pairs, i.e. independent of genetic effects and age, 1) the amount of subcutaneous fat inversely correlated with serum total and free testosterone, DHT, and sex hormone-binding globulin (SHBG) concentrations (P <0.01 for all), 2) infra-abdominal fat with total testosterone and SHBG (P <0.05), and 3) liver fat with SHBG (P = 0.006). Also, 4) general and intra-abdominal adiposity correlated positively with mRNA expressions of AKR1C2, HSD11B1, and aromatase in adipose tissue (P <0.05). In conclusion, acquired adiposity was associated with decreased serum DHT and increased estrogen concentrations, independent of genetic factors and age. The reduction of DHT could be linked to its increased degradation (by AKR1C2 and HSD11B1) and increased estrogen levels to increased adiposity-related expression of aromatase in adipose tissue.
  • Laakso, Saila; Viljakainen, Heli; Lipsanen-Nyman, Marita; Turpeinen, Ursula; Ivaska, Kaisa K.; Anand-Ivell, Ravinder; Ivell, Richard; Mäkitie, Outi (2018)
    Background: Previous studies suggest increased risk for hypoandrogenism and fractures in men with obesity. We aimed to describe the effects of severe childhood-onset obesity on the cross talk between metabolic state, testes, and skeleton at late puberty. Methods: A cohort of adolescent and young adult males with severe childhood-onset obesity (n = 21, mean age 18.5 years) and an age-matched control group were assessed for testicular hormones and X-ray absorptiometry-derived bone mass. Results: Current median body mass indexes for the obese and control subjects were 37.4 and 22.9. Severe early-onset obesity manifested with lower free testosterone (median [interquartile range] 244 [194-332] vs. 403 [293-463] pmol/L, p = 0.002). Lower insulin-like 3 (1.02 [0.82-1.23] vs. 1.22 [1.01-1.46] ng/mL, p = 0.045) and lower ratio of testosterone to luteinizing hormone (2.81 [1.96-3.98] vs. 4.10 [3.03-5.83] nmol/IU, p = 0.008) suggested disrupted Leydig cell function. The degree of current obesity inversely correlated with free testosterone (t = -0.516, p = 0.003), which in turn correlated positively with bone area at all measurement sites in males with childhood-onset obesity. Conclusions: Severe childhood-onset obesity is associated with impaired Leydig cell function in young men and lower free testosterone may contribute to impaired skeletal characteristics. (C) 2018 S. Karger AG, Basel
  • Tikkanen, Roope; Saukkonen, Tero; Fex, Malin; Bennet, Hedvig; Rautiainen, Marja-Riitta; Paunio, Tiina; Koskinen, Mika; Panarsky, Rony; Bevilacqua, Laura; Sjoberg, Rickard L.; Tiihonen, Jari; Virkkunen, Matti (2016)
    Herein, we examined insulin resistance (IR), insulin sensitivity (IS), beta cell activity, and glucose metabolism in subjects with antisocial personality disorder (ASPD), and whether the serotonin 2B (5-HT2B) receptor and testosterone have a role in energy metabolism. A cohort of subjects belonging to a founder population that included 98 ASPD males, aged 25-30, was divided into groups based on the presence of a heterozygous 5-HT2B receptor loss-of-function gene mutation (HTR2B Q20*; n = 9) or not (n = 89). Serum glucose and insulin levels were measured in a 5 h oral glucose tolerance test (75 g) and indices describing IR, IS, and beta cell activity were calculated. Body mass index (BMI) was also determined. Concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid were measured in cerebrospinal fluid, and testosterone levels from serum. An IR-like state comprising high IR, low IS, and high beta cell activity indices was observed among ASPD subjects without the HTR2B Q20* allele. By contrast, being an ASPD HTR2B Q20* carrier appeared to be preventive of these pathophysiologies. The HTR2B Q20* allele and testosterone predicted lower BMI independently, but an interaction between HTR2B Q20* and testosterone lead to increased insulin sensitivity among HTR2B Q20* carriers with low testosterone levels. The HTR2B Q20* allele also predicted reduced beta cell activity and enhanced glucose metabolism. Reduced 5-HT2B receptor function at low or normal testosterone levels may be protective of obesity. Results were observed among Finnish males having an antisocial personality disorder, which limits the generality. (C) 2016 Elsevier Ltd. All rights reserved.