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PubMed1980

The relationship of sex role to self-concept.

Investigated the relationship of sex role in 136 Ss as measured by the Bem Sex Role Inventory to measures of self-concept and overt anxiety. Persons who rated themselves low in both masculine and feminine attributes were found to have significantly poorer self-concept than both androgynous and masculine Ss, which suggests that this group should be distinguished from high-high scorers labeled as androgynous. There was no significant difference in self-concept between masculine and androgynous Ss, and the masculine group reported significantly lower levels of anxiety. These findings support a previous contention that it is the presence of masculine attributes rather than a balance of masculinity and femininity that is crucial to personal adjustment.

Adult↗
PubMed1995

Endocrine sex reversal of gonads by the aromatase inhibitor Letrozole (CGS 20267) in Emys orbicularis, a turtle with temperature-dependent sex determination.

In embryos of Emys orbicularis, the sexual differentiation of gonads is influenced by the incubation temperature of eggs. Estrogens administered during the thermosensitive period result in the feminization of gonads at 25 degrees (male-producing temperature), whereas an antiestrogen or aromatase inhibitors masculinize the gonads at 30 degrees (female-producing temperature). The nonsteroidal aromatase inhibitor Letrozole induces gonads with different degrees of masculinization, from ovary-like to testis-like. The present study examines the endocrine function of such masculinized gonads, at the end of embryonic life. Aromatase activity (which is involved in estrogen synthesis in ovary) and the status of Müllerian ducts (the regression of which reflects the secretion of a putative anti-Müllerian hormone by the Sertoli cells) were examined. One month after treatment with Letrozole, the gonads of embryos presented various levels of aromatase activity. There was a strong correlation among aromatase activity, gonadal structure, and Müllerian duct status; high levels of aromatase (similar or close to those in control females) were found in ovary-like gonads; intermediate levels were found in gonads (masculinized ovaries or ovotestes?) exhibiting a cortex and a composite medulla containing a mixture of ovarian lacunae and testicular cord-like structures; low levels (similar or close to those in control males) were found in strongly masculinized gonads (testis-like or ovotestes). Müllerian ducts were regressing in the majority of embryos with gonads containing low levels of aromatase activity. In these individuals, gonads functioned as embryonic testes. These results confirm the implication of estrogens in gonadal differentiation. The origin of these hormones is controversial, so that the aromatase activity was compared in gonads, in the undissociated adrenal-mesonephric complex (AM), and in different parts of this complex during the thermosensitive period. At the female-producing temperature, the aromatase activity per unit of tissue increased in differentiating ovaries but it was low in AM and similar to that found in AM at male-producing temperature. In embryos whose gonads had been masculinized by early treatment with Letrozole, aromatase activity was unchanged in AM. These results suggest that the main source of estrogens involved in ovarian differentiation is the gonad itself.

Analysis of Variance↗
PubMed1997

The effects of testicular tissue and prehatching inhibition of estrogen synthesis on the development of courtship and copulatory behavior in zebra finches.

As in many mammalian and avian species, testicular androgens or their metabolites activate courtship and copulatory behaviors in adult male zebra finches. However, studies of sexual differentiation of these behaviors and related anatomical structures provide conflicting results. For example, posthatching estradiol can both masculinize courtship and the neural structures involved in song in females and inhibit the development of masculine copulation in males. These and other results have led to the hypotheses that (1) testicular androgens are converted to estradiol in the brain of developing males, and estradiol serves to masculinize the song system, whereas (2) estradiol secretion by the female ovary allows feminine rather than masculine copulatory behavior to develop. Treating embryonic zebra finches with the estrogen synthesis inhibitor fadrozole causes functional testicular tissue to develop in genetic females. The present study investigated the effects of such treatment on the development of singing and copulatory behavior as well as song system anatomy in males and females. While exogenous testosterone facilitated the display of sexual behaviors in adult males, the testicular tissue in females had no masculinizing effect on the production of audible courtship song or copulation. Their song control nuclei were also not masculinized, even in individuals lacking ovarian tissue. In contrast, embryonic inhibition of estrogen synthesis in males significantly stimulated song production. These results suggest that while manipulations of steroid hormone exposure can influence the display of sexual behaviors, gonadal secretions may not be required for normal sexual differentiation of the song system in zebra finches.

Animals↗
PubMed2001

Sex differences in children's free drawings: a study on girls with congenital adrenal hyperplasia.

Sex differences are recognized in children's free drawings with respect to motifs, colors, figure compositions, and expression. Boys tend to draw mobile objects and mechanical objects with dark or cold colors and often use bird's-eye-view composition when they draw pictures, whereas girls like to draw human motifs (especially girls and women), flowers, and butterflies with light and warm colors and tend to arrange motifs in a row on the ground. Analyses were made on the drawings of girls with congenital adrenal hyperplasia (CAH) and unaffected boys and girls, using masculine and feminine indexes. Sex difference in masculine and feminine indexes was clear in the drawings by unaffected boys and girls. Their drawings do not or mostly do not contain characteristics typical of the opposite sex. Compared with those of unaffected girls, the pictures of CAH girls more strongly showed masculine characteristics. The feminine index for the pictures of CAH girls was significantly lower than that for unaffected girls, while the masculine index for CAH girls was significantly higher than that for unaffected girls. Furthermore, the masculine index for CAH girls was not significantly different from that of unaffected boys. These results suggest that androgen exposure during fetal life may contribute to shaping masculine characteristics in children's free drawings.

Adrenal Hyperplasia, Congenital↗
PubMed1997

Rapid preparation method for technetium-99m bicisate.

The method currently recommended for the preparation of technetium-99m bicisate (99mTc-bicisate) requires a lengthy 30-min incubation at room temperature. The purpose of this study was to evaluate an alternative method to shorten the preparation time. 99mTc-bicisate was prepared with 3.7 GBq (100 mCi) 99mTc according to the manufacturer's instructions, except for the final incubation step, which was replaced with the microwave heating procedure. A standard thin-layer chromatography (TLC) method (i.e., Baker-Flex silica gel IB-F TLC plate with ethyl acetate as mobile phase) was used for the determination of the radiochemical purity (RCP) of 99mTc-bicisate. Our evaluation with different microwave heating processes (300 W with different heating times) demonstrated that as the microwave heating temperature was increased (i.e., 44 masculine-71 masculine C), an increased percentage of samples reached 95% within 5 min post preparation (n=58). The highest RCP value (i.e., 97.4%+/-0.5%, n=10) could be obtained immediately after an 8-s microwave heating time at 300 W (microwave temperature at 69 masculine C), and an average RCP value of 96.4%+/-1.3% (n=90) was maintained throughout the 24-h evaluation period. However, the trend seemed to reverse at higher microwave temperatures (i.e., 76 masculine-90 masculine C), which reconfirmed our initial findings that overheating had no benefit for the preparation of 99mTc-bicisate. To ensure that temperature was the only determining factor, a hot water incubator set at 69 masculine C was used (n=6). Similar RCP results were achieved. In conclusion, the use of a microwave oven at a low heat cycle provides a rapid and efficient way to prepare 99mTc-bicisate.

Chromatography, Thin Layer↗
PubMed1985

Genetic analysis of developmental mechanics in hydra. XI. Mechanism of sex reversal by heterosexual parabiosis.

Sex change from female to male occurs at a high rate in hydra when a female polyp is exposed to a male polyp by parabiosis for a limited length of time. The mechanism of this masculinization process was investigated. When a male strain which produces immotile sperm was used to masculinize female strains, the resultant masculinized animals produced only immotile sperm. Evidence was also obtained which indicated that the original female interstitial cells remained in large numbers in the masculinized animals but did not differentiate into gametic cells. These observations suggest that masculinization is achieved not by the hypothetical "masculinizing factor" but by the migration of the male interstitial cells from the male to the female tissue during parabiosis.

Animals↗
PubMed1987

Estrogenic contributions to sexual differentiation in the female guinea pig: influences of diethylstilbestrol and tamoxifen on neural, behavioral, and ovarian development.

We administered the synthetic estrogen, diethylstilbestrol (DES), or the antiestrogen, tamoxifen, to pregnant guinea pigs and observed the consequences for sexual differentiation of their female offspring. Hormones were administered during the period when treatment of fetuses with testosterone influences the development of sex-related traits (approximately Days 30 to 65 of gestation). Ovarian function, masculine and feminine sexual behavior, and the structure of a sexually dimorphic neural region in the preoptic area were assessed in adulthood in hormone-exposed animals and in oil-treated and untreated controls. Prenatal exposure to DES dipropionate (DESDP) caused masculinization and defeminization. DESDP-treated females mounted more than control females, both without hormonal stimulation and when given testosterone propionate (TP) as adults. The sexually dimorphic neural region was also masculinized in these females. In regard to defeminization, they showed delayed vaginal opening, impaired progesterone (P) production, an absence of corpora lutea, and impaired lordosis and mounting responses to estradiol benzoate (EB) and P. Prenatal treatment with tamoxifen produced a complicated pattern of results. Tamoxifen-exposed females evidenced less masculine-typical behavior, showing diminished mounting without hormonal stimulation and in response to TP. However, they also showed delayed vaginal opening, enhanced P production, and impaired mounting in response to EB and P. Their lordosis behavior and the volume of the sexually dimorphic neural region were unaffected. These results suggest that estrogens play a substantial role in sexual differentiation in the guinea pig. High levels of estrogen promote masculine-typical development, and unusually low levels may impair some aspects of both masculine-typical and feminine-typical development.

Animals↗
PubMed1985

Differential effects of perinatal androgen treatment on sexually dimorphic characteristics in rats.

Rats were treated with testosterone propionate (TP) or oil (O) beginning in midgestation (group TTT), late gestation (group OTT), neonatally (group OOT), or were left untreated until adulthood (group OOO). At 40 days of age all animals were gonadectomized, received implants of TP in silastic capsules, and were tested in subsequent weeks for masculine copulatory behavior and ex copula phallic responses. Postmortem measures were taken of genital structures and of sexually dimorphic spinal nuclei. Males treated perinatally with androgen were unaffected or exhibited reduced masculinization except on two measures, i.e., number of penile flips and number of cells in the dorsolateral motor nucleus of the lumbar spinal cord, which reflected virilization greater than in normal males. All perinatally androgenized females showed virilization on almost every measure taken of their morphology and behavior. Relative to OOO females, the greatest increases in masculinization were evident in OOT and OTT females. No additional masculinization was detected in TTT females. Only among the TTT rats were males not reliably more masculine than females, but that usually was due to the reduced masculinization of TTT males. Four broad classes of influence characterized the effects of perinatal androgen treatment; these classes may reflect differences in the developmental courses of the variables measured.

Animals↗
PubMed2005

Spatial memory performance in androgen insensitive male rats.

Masculinization of the developing rodent brain critically depends on the process of aromatization of circulating testosterone (T) to its estrogenic metabolite 17beta-estradiol, which subsequently interacts with estrogen receptors to permanently masculinize the brain. However, it remains unclear what role other androgenic mechanisms may play in the process of masculinization. A novel way of examining this is through the study of male rats that express the tfm mutation of the androgen receptor (AR) gene; such males are fully androgen insensitive and manifest a female phenotype due to a failure of AR-mediated masculinization of peripheral structures. Because tfm-affected males develop secretory testes and have near-normal T titers during development, aromatization would be expected to proceed normally, and brain mechanisms may be developmentally masculinized despite the feminized periphery. We compared tfm-affected males (X(tfm)Y) with normal males and females in the Morris Water Maze, a task in which males typically perform better than females. Performance of tfm-affected males was intermediate between that of normal males and females. While an overall male superiority was found in the task, the X(tfm)Y group reached male-typical escape latencies faster than females. Furthermore, in the X(tfm)Y group, the granule cell layer of the dentate gyrus was significantly larger than in females. These results support the suggestion that that AR mediated mechanisms contribute to the masculinization of spatial behaviours and hippocampal morphology, and this may be independent of estrogenic processes.

Analysis of Variance↗
PubMed1991

Development of functional sex differences in the larynx of Xenopus laevis.

Three laryngeal properties associated with the production of masculine song--laryngeal muscle tension, fiber twitch type, and fiber recruitment--are markedly sexually dimorphic in adult Xenopus laevis frogs. To elucidate the pattern of sexual differentiation, tension and fiber recruitment in male and female larynges and fiber twitch type in male larynges were examined throughout postmetamorphic development. Masculinization of male laryngeal properties begins early in postmetamorphic development and continues until adulthood. In contrast, tension and fiber recruitment in females do not change after the end of metamorphosis. Laryngeal muscle tension and fiber type are gradually and progressively masculinized; the temporal pattern of masculinization is very similar for these properties. Fiber recruitment, on the other hand, appears to masculinize in a stepwise manner. Masculinization of all three properties is highly correlated with larynx weight in males. We have used this relation to divide postmetamorphic development into seven stages associated with key events in sexual differentiation. This staging scheme provides an important experimental tool for studying the hormonal regulation of sexual differentiation, the subject of the accompanying paper.

Animals↗
PubMed2004

Prenatal androgenization affects gender-related behavior but not gender identity in 5-12-year-old girls with congenital adrenal hyperplasia.

Gender assignment of children with intersexuality and related conditions has recently become highly controversial. On the basis of extensive animal research and a few human case reports, some authors have proposed the putative masculinization of the brain by prenatal hormones-indicated by the degree of genital masculinization-as the decisive criterion of gender assignment and have derived the recommendation that 46,XX newborns with congenital adrenal hyperplasia (CAH) and full genital masculinization should be assigned to the male gender. The purpose of this study was to test in CAH girls of middle childhood the assumption that prenatal androgens determine the development of gender identity. Fifteen girls with CAH (range of genital Prader stage, 2-4/5), 30 control girls, and 16 control boys (age range, 5-12 years) underwent 2 gender-play observation sessions, and a gender identity interview yielding scales of gender confusion/dysphoria. About half a year earlier, mothers had completed 2 questionnaires concerning their children's gender-related behavior. The results showed that, as expected, CAH girls scored more masculine than control girls on all scales measuring gender-related behavior, with robust effect sizes. By contrast, neither conventionally significant differences nor trends were found on the 3 scales of the gender identity interview. We conclude that prenatal androgenization of 46,XX fetuses leads to marked masculinization of later gender-related behavior, but the absence of any increased gender-identity confusion/dysphoria does not indicate a direct determination of gender identity by prenatal androgens and does not, therefore, support a male gender assignment at birth of the most markedly masculinized girls.

Adrenal Hyperplasia, Congenital↗
PubMed2006

Social role and birth cohort influences on gender-linked personality traits in women: a 20-year longitudinal analysis.

Growth curve modeling was used to examine the impact of social role experiences (e.g., marital support, occupational prestige) and birth cohort on mean-level differences and age-related changes in positive personality traits indicative of either femininity or masculinity in 758 mothers heterogeneous in age, assessed 4 times over 2 decades. Both femininity and masculinity increased significantly from mean ages 39 through 59; each was predictive of an age change in the other. Low masculinity was associated with a more rapid increase in femininity, whereas high occupational prestige decreased the magnitude of association between masculinity and femininity. Femininity increased with more marital support but decreased with unmarried status, more children at home, and working full or part time; among full-time workers, that effect was modified by marital support. Masculinity increased with full-time work and high occupational prestige. A trend for differing levels of femininity, and contrasting associations of masculinity with femininity and marital conflict in women born after 1944 compared with those born earlier, suggests shifting social norms and gender relations in the marital role.

Adult↗
PubMed2005

Men behaving differently: South African men since 1994.

Liberal versions of sexuality, which mark South Africa's new democracy, have had a number of highly contradictory consequences for women and men, as old notions of masculinity and male privilege have been destabilized. The transition to democracy has precipitated a crisis of masculinity. Orthodox notions of masculinity are being challenged and new versions of masculinity are emerging in their place. Some men are seeking to be part of a new social order while others are defensively clinging to more familiar routines. Drawing on in-depth interviews with young African working class men, this paper explores new masculinities in contemporary South Africa. It examines how men negotiate their manhood in a period of social turbulence and transition. Masculinity, male sexuality, and the expectations which men have of themselves, each other and women are contested and in crisis.

Adult↗
PubMed1981

Sexual differentiation of hepatic metabolism of corticosterone and testosterone in the rat.

The metabolism of corticosterone and testosterone has been studied in vitro in separate aliquots of the same homogenates of livers from neonatally masculinized and non-masculinized adult castrate male rats. The recovered metabolites were separated by TLC and identified by the combined use of GLC and appropriate derivative formation. The major effect of neonatal masculinization upon the metabolism of both steroids was to increase the ratio of 3 beta : 3 alpha metabolites but this effect was much more prominent in the metabolism of corticosterone than of testosterone. Only 5 alpha metabolites of corticosterone were found, whereas a minor amount of 5 beta products appeared in the case of testosterone. Reduction at C-20 accounted for only about 5% of the metabolism of corticosterone with the exclusive formation of 20 beta-hydroxy derivatives in the non-masculinized liver, but of both 20 alpha and 20 beta products in the masculinized liver. Small amounts of acetylated androstane 3,17-diols and 3-hydroxy-17-ketones were formed, apparently by enzymic reactions that are influenced by neonatal masculinization.

Animals↗
PubMed2002

Partnership status and the temporal context of relationships influence human female preferences for sexual dimorphism in male face shape.

Secondary sexual characteristics may indicate quality of the immune system and therefore a preference for masculinity may confer genetic benefits to offspring; however, high masculinity may be associated with costs of decreased paternal investment. The current study examined women's preferences for masculinity in male faces by using computer graphics to allow transformation between feminine and masculine versions of individual male faces. We found that preferences for masculinity are increased when women either have a partner or are considering a short-term relationship. Such preferences are potentially adaptive, serving to: (i) maximize parental investment and cooperation in long-term relationships by biasing choices towards feminine faced males, and (ii) maximize possible good-gene benefits of short-term or extra-pair partners by biasing choices towards masculine faced males. We also found that individuals using oral contraception do not show the above effects, indicating that such hormonal intervention potentially disrupts women's choices for evolutionarily relevant benefits from males.

Adolescent↗
PubMed1995

Psychiatrists' and non-physician psychotherapists' beliefs about gender-appropriate behavior: a comparison.

We adapted the Bem Sex-Role Inventory to survey therapists' beliefs about gender-appropriate behavior for hypothetical patients. We previously studied psychiatrists, finding that women were more likely to choose masculine or androgynous (high masculine and high feminine) traits as optimal for female patients while men were more likely to choose the undifferentiated (low masculine and low feminine) category for patients of either sex. In this study we used the same measure to compare psychologists and social workers to the psychiatrists, to determine the effect of medical education on these attitudes. We found that regardless of educational background, women were more likely to choose the androgynous category and men were more likely to choose the undifferentiated category. Women psychiatrists were more likely to choose masculine traits as optimal than were women non-physician therapists. Male therapists of all backgrounds were least likely to choose masculine traits as optimal for either male or female patients. Medical education per se does not seem to determine attitudes about gender-appropriate behavior. Men entering professions in which they are concerned about others' emotional well-being may have less stereotypically masculine beliefs about gender-appropriate behavior than women entering the same fields. Possible reasons for this difference are discussed.

Adult↗
PubMed2002

Effects of perinatal exposure to PCBs and dioxins on play behavior in Dutch children at school age.

Polychlorinated biphenyls (PCBs) and dioxins are known as neurotoxic compounds that may modulate sex steroid hormones. Steroid hormones play a mediating role in brain development and may influence behaviors that show sex differences, such as childhood play behavior. In this study we evaluated the effects of perinatal exposure to environmental levels of PCBs and dioxins on childhood play behavior and whether the effects showed sex differences. As part of the follow-up to the Dutch PCB/dioxin study at school age, we used the Pre-School Activity Inventory (PSAI) to assess play behavior in the Rotterdam cohort (n = 207). The PSAI assesses masculine or feminine play behavior scored on three subscales: masculine, feminine, and composite. Prenatal exposure to PCBs was defined as the sum of PCB 118, 138, 153, and 180 in maternal and cord plasma and breast milk. For breast milk we measured additional PCBs as well as 17 dioxins. Respondents returned 160 questionnaires (age 7.5 years +/- 0.4). Effects of prenatal exposure to PCBs, measured in maternal and cord plasma, on the masculine and composite scales were different for boys and girls (p <.05). In boys, higher prenatal PCB levels were related with less masculinized play, assessed by the masculine scale (p(maternal) =.042; p(cord) =.001) and composite scale (p(cord) =.011), whereas in girls higher PCB levels were associated with more masculinized play, assessed by the composite scale (p(PCBmilk) =.028). Higher prenatal dioxin levels were associated with more feminized play in boys as well as girls, assessed by the feminine scale (p =.048). These effects suggest prenatal steroid hormone imbalances caused by prenatal exposure to environmental levels of PCBs, dioxins, and other related organochlorine compounds.

Adult↗
PubMed2002

Aromatase activity in the ovary and brain of the eastern mosquitofish (Gambusia holbrooki) exposed to paper mill effluent.

Studies have shown that female mosquitofish living downstream of a paper mill located on the Fenholloway River, Florida, have masculinized secondary sex characteristics, including altered anal fin development and reproductive behavior. Masculinization can be caused by exposure to androgens in the water or from an alteration in aromatase activity in the fish. We hypothesized that aromatase activity would be inhibited by a component(s) of the paper mill effluent. Aromatase inhibition could masculinize the hormonal profile and, subsequently, secondary sex characteristics of the exposed females. Therefore, we predicted that ovarian and brain aromatase activity would be lower in the female mosquitofish from the Fenholloway River compared with the reference site, the Econfina River. Adult females were collected and standard length, body mass, anal fin length, and segment number were measured. Ovarian and brain aromatase activity were determined using a tritiated water assay. Fenholloway females had masculinized anal fin development as indicated by an increase in the number of segments in the longest anal fin ray (p < 0.0001), yet the length of the ray did not differ between sites (p = 0.95). Fenholloway females exhibited higher ovarian (p = 0.0039) and brain (p = 0.0003) aromatase activity compared with reference site fish. These data do not support aromatase inhibition as the mechanism for masculinization, suggesting that the masculinization of the Fenholloway female mosquitofish is due to androgenic contaminants. Future studies should examine the relationship between aromatase enzyme activity and exposure to environmental androgens.

Animals↗