An experiment was performed to study the effect of chronic ethanol administration on intermale aggression in rats using a 24-hour resident-intruder test. During the resident-intruder test residents displayed virtually all of the agonistic behaviors, and intruders displayed virtually all of the defensive behaviors. Intruders treated with ethanol displayed more defensive behavior and elicited more agonistic behavior than control intruders. Twenty minutes into the resident-intruder test intruders showed the greatest increase in corticosterone (338% vs. 129%), while residents showed the greatest increase in testosterone (103% vs. 18%). On the 2nd day of the resident-intruder test intruders lost more weight than residents (21.5 g vs. 10.2 g). Plasma corticosterone levels remained elevated for the intruders, and in particular for those intruders displaying defensive behaviors regardless of the resident's behavior. Plasma testosterone levels remained elevated for those residents that were paired with intruders that displayed defensive behaviors regardless of the resident's behavior. The frequency and severity of biting attacks by ethanol residents was significantly greater than that of control residents. In addition, the locus of biting attack shifted from the upper back of intruders paired with control residents to the flanks, tail, lower feet, and ventral surface on intruders paired with ethanol residents. 相似文献
Behavioral, physiological (i.e., endocrine), and anatomical consequences of crowding in mice were studied in a situation where animals were in auditory, visual, olfactory, and tactile contact but restrained from full physical interactions, to prevent overt aggression. Males that cohabited with females undisturbed by neighboring conspecifics showed greater propensity to attack same-sex intruders and had higher plasma testosterone levels than did their “crowded” counterparts, that is, males cohabiting with females and housed adjacent to other male/female pairs. In this respect, the latter animals resembled submissive males. However, a significant increase in weight of androgen-dependent target organs (i.e., seminal vesicles and preputial glands) was found in crowded males. These data indicate that despite the observed inhibition of social aggression these males are not physiologically comparable (homologous) to male mice that experienced defeat and the stress of submission during fighting. The intriguing possibility that different conversion pathway of testosterone are accelerated, as a result of social communication, in males living in these two environments and the behavioral implications of these possibilities are discussed. Finally, the parental behavior of crowded animals, although not freely interacting with each other, was disrupted, causing a marked decrease in reproductive success. In this situation a high incidence of infanticide of their offspring by both parents was observed, whereas this behavior was virtually absent in non-crowded male/female pairs. 相似文献
Background: Testosterone therapy is the predominant treatment for voice masculinization in transgender patients. Although lowering of voice fundamental frequency (f0) occurs with testosterone therapy, evidence suggests voice and gender identity may not fully align—i.e., voice-gender congruence may not be achieved—with its use.
Aim: This meta-analytic review evaluates the effectiveness of testosterone therapy to masculinize voice in transgender patients.
Methods: Multiple electronic databases were queried (inclusion dates: from database inception up to October 27, 2017) to identify original research on voice masculinization using testosterone therapy. Nineteen articles were included in this meta-analytic review, which followed PRISMA guidelines. In addition to qualitative analyses, random effects proportion meta-analyses were performed on data related to f0, voice-gender congruence, voice problems, and satisfaction with voice.
Results: A meta-analysis on f0 data showed after 1 year of testosterone therapy a combined estimate of 21% of participants (95% confidence interval [CI]: 5%–43%; I2: 59.9%) did not achieve cisgender male normative frequencies (f0 ≤ 131 Hz). Meta-analyses on incomplete voice-gender congruence and voice problems indicated combined estimates of 21% (95% CI: 10%–34%; I2: 0.0%) and 46% (95% CI: 14%–79%; I2: 90.2%), respectively. Regarding incomplete satisfaction with voice, a meta-analysis showed a combined estimate of 16% (95% CI: 7%–28%; I2: 0.0%).
Discussion: We found that not all transgender patients using testosterone therapy to masculinize voice should expect f0 lowering to cisgender male normative frequencies after 1 year. The vocal transition may involve voice problems for many patients, and some might not achieve voice-gender congruence without additional, voice-specific intervention. Given these findings, a voice evaluation should occur prior to initiating testosterone therapy and involve counseling on expectations for voice. Transgender patients who pursue voice masculinization may need management from laryngology and speech and language therapy to improve voice-gender congruence, mitigate voice problems, and increase satisfaction with voice. 相似文献