Ein neuer sehr interessanter biologischer Sonderfall.
Aus der Wikipedia:
Isolated hypogonadotropic hypogonadism (IHH), also called idiopathic or congenital hypogonadotropic hypogonadism (CHH), as well as isolated or congenital gonadotropin-releasing hormone deficiency (IGD), is a condition which results in a small subset of cases of hypogonadotropic hypogonadism (HH) due to deficiency in or insensitivity to gonadotropin-releasing hormone (GnRH) where the function and anatomy of the anterior pituitary is otherwise normal and secondary causes of HH are not present
Congenital hypogonadotropic hypogonadism presents as hypogonadism, e.g., reduced or absent puberty, low libido, infertility, etc. due to an impaired release of the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), and a resultant lack of sex steroid and peptides production by the gonads.
Und aus dem Artikel zu Gonadotropin:
Gonadotropins are released under the control of gonadotropin-releasing hormone (GnRH) from the arcuate nucleus and preoptic area of the hypothalamus. The gonads — testes and ovaries — are the primary target organs for LH and FSH. The gonadotropins affect multiple cell types and elicit multiple responses from the target organs. As a simplified generalization, LH stimulates the Leydig cells of the testes and the theca cells of the ovaries to produce testosterone (and indirectly estradiol), whereas FSH stimulates the spermatogenic tissue of the testes and the granulosa cells of ovarian follicles, as well as stimulating production of estrogen by the ovaries.
Aus einer Studie dazu: „Evidence for Perinatal Steroid Influence on Human Sexual Orientation and Gendered Behavior“
In laboratory animals, exposure to gonadal steroid hormones before and immediately after birth can exert permanent effects on many behaviors, particularly reproductive behaviors. The extent to which such effects occur in humans remains an open question, but several lines of evidence indicate that perinatal levels of both androgens and estrogens may affect adult human psychology and behavior, including sexual orientation and gender nonconformity. Some putative indicators of prenatal androgen exposure, including the ratio of the length of the index finger to that of the ring finger (2D:4D), have repeatedly indicated that lesbians, on average, were exposed to more prenatal androgens than straight women, suggesting that sufficient fetal androgen exposure predisposes a fetus to gynephilia (attraction to women) at maturity. The digit ratios of gay men do not differ from those of straight men, suggesting that prenatal androgen levels are not responsible for their androphilia (attraction to men). However, evidence that gay men who prefer an insertive anal sex role (ASR) have more masculine digit ratios than those preferring a receptive ASR suggests that early androgens influence some sexual preferences in men. Furthermore, digit ratios among gay men have been found to correlate with recalled childhood gender nonconformity (CGN). People with isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) offer further insight into the effects of perinatal gonadal steroid exposure. In people with IGD, gonadal hormone production is low or absent after the first trimester of gestation. However, because placental gonadotropins drive gonadal hormone secretion during the first trimester when genitalia sexually differentiate, individuals with IGD are unambiguously male or female at birth, consistent with their chromosomal and gonadal sex. Men with IGD report greater CGN, again suggesting that perinatal androgen exposure contributes to male-typical behavioral patterns in humans. Interestingly, women with IGD report less androphilia and more bisexuality than control women, suggesting that perinatal ovarian steroids in females typically augment androphilia in adulthood. Taken together, these findings indicate that the perinatal hormonal milieu influences human sexual orientation and gender conformity.
Der untere Teil übersetzt:
Menschen mit isoliertem Gonadotropin-Releasing-Hormon (GnRH)-Mangel (IGD) bieten weitere Einblicke in die Auswirkungen der perinatalen Exposition gegenüber gonadalen Steroiden. Bei Menschen mit IGD ist die gonadale Hormonproduktion nach dem ersten Trimester der Schwangerschaft gering oder gar nicht vorhanden. Da jedoch die Gonadotropine der Plazenta die gonadale Hormonsekretion während des ersten Trimesters anregen, wenn sich die Genitalien geschlechtlich differenzieren, sind Menschen mit IGD bei der Geburt eindeutig männlich oder weiblich, was mit ihrem chromosomalen und gonadalen Geschlecht übereinstimmt. Männer mit IGD weisen eine größere Gender-Nonkonformität in der Kindheit (CGN) auf, was wiederum darauf hindeutet, dass die perinatale Androgenexposition zu männlich-typischen Verhaltensmustern beim Menschen beiträgt. Interessanterweise berichten Frauen mit IGD über weniger Androphilie und mehr Bisexualität als Kontrollfrauen, was darauf hindeutet, dass perinatale ovarielle Steroide bei Frauen typischerweise die Androphilie im Erwachsenenalter verstärken. Zusammengenommen deuten diese Ergebnisse darauf hin, dass das perinatale hormonelle Milieu die sexuelle Orientierung und die Geschlechtskonformität des Menschen beeinflusst.
Und noch eine interessante Studie aus dem Bereich:
The contributions of gonadal hormones to the development of human behavioral sex differences are subjects of intense scientific and social interest. Isolated gonadotropin-releasing-hormone deficiency (IGD) is a rare endocrine disorder that can reveal a possible role of early gonadal hormones. IGD is characterized by low or absent gonadal hormone production after the first trimester of gestation, but external genitalia and hence gender of rearing are concordant with chromosomal and gonadal sex. We investigated recalled childhood gender nonconformity in men (n = 65) and women (n = 32) with IGD and typically developing men (n = 463) and women (n = 1,207). Men with IGD showed elevated childhood gender nonconformity, particularly if they also reported undescended testes at birth, a marker of low perinatal androgens. Women with IGD did not differ from typically developing women. These results indicate that early androgen exposure after the first trimester contributes to male-typical gender-role behaviors in childhood.
Quelle: Low Perinatal Androgens Predict Recalled Childhood Gender Nonconformity in Men
Und aus einer Besprechung der Studie:
The researchers looked at 97 individuals with IGD and 1665 individuals with typical hormonal development. The researchers recruited IGD subjects through collaborations at Massachusetts General Hospital, Harvard Medical and the National Institute of Child Health and Human Development and from online support groups for people with IGD. Because only one in 130,000 people has IGD the number of IGD subjects was necessarily low. By comparing the two groups, the researchers attempted to isolate the direct influence of sex hormones on the developing brain from the influence of gender socialization — boys being encouraged toward active play, girls pushed to more passive pursuits, for example — because all subjects would have been similarly socialized according to their physical sex.
The researchers asked subjects to recall behaviors they had as children.
„We asked them, ‚When you read a book, were you the male or female in the story?‘, ‚Where your friends boys or girls?‘, ‚Did you play with dolls or trucks?‘,“ said Talia N. Shirazi, doctoral recipient in anthropology now working in the reproductive health industry.
According to Puts, such so called childhood gender role behaviors are among the largest behavioral sex differences. Typically, males will say they were the male character, played with other boys and preferred trucks, while females will say they were the female character, played with other girls and preferred dolls.
However, males with IGD reported more gender non-conforming in these types of behaviors. The researchers report in an upcoming issue of Psychological Science, that men with IGD recalled a higher level of childhood gender non-conformity than typical men, while women with IGD did not differ from typical women in childhood gender conformity.
‚“We don’t see this effect in the women with IGD,“ said Shirazi.
This indicates that having low levels of ovarian hormones such as estrogen does not have a large effect on childhood gender role behaviors, she added.
„Our results suggest that in humans, androgens, such as testosterone produced by the testes, influence male brain development directly as they do in other mammals, rather than only indirectly by influencing external appearance and consequently gender socialization,“ said Puts. „Both the direct influence of androgens on the developing brain and gender socialization probably play important roles in producing sex differences in childhood behavior.“
Und noch ein paar Studien:
Ovarian estrogens may influence the development of the human brain and behavior, but there are few opportunities to test this possibility. Isolated GnRH deficiency (IGD) is a rare endocrine disorder that could provide evidence for the role of estrogens in organizing sexually differentiated phenotypes: Unlike typical development, development in individuals with IGD is characterized by low or absent gonadal hormone production after the first trimester of gestation. Because external genitalia develop in the first trimester, external appearance is nevertheless concordant with gonadal sex in people with IGD. We therefore investigated the effects of gonadal hormones on sexual orientation by comparing participants with IGD (n = 97) to controls (n = 1670). Women with IGD reported lower male-attraction compared with typically developing women. In contrast, no consistent sexuality differences between IGD and typically developing men were evident. Ovarian hormones after the first trimester appear to influence female-typical dimensions of sexual orientation.
Quelle: Evidence that perinatal ovarian hormones promote women’s sexual attraction to men
• We tested whether CNS sensitivity to androgens decreases across puberty in human males.
• Meta-analysis suggested a robust effect of pubertal timing on visuospatial abilities.
• Earlier androgen exposure may lead to greater cognitive sex-typicality in men.
Experiments in male rodents demonstrate that sensitivity to the organizational effects of steroid hormones decreases across the pubertal window, with earlier androgen exposure leading to greater masculinization of the brain and behavior. Similarly, some research suggests the timing of peripubertal exposure to sex steroids influences aspects of human psychology, including visuospatial cognition. However, prior studies have been limited by small samples and/or imprecise measures of pubertal timing. We conducted 4 studies to clarify whether the timing of peripubertal hormone exposure predicts performance on male-typed tests of spatial cognition in adulthood. In Studies 1 (n = 1095) and 2 (n = 173), we investigated associations between recalled pubertal age and spatial cognition in typically developing men, controlling for current testosterone levels in Study 2. In Study 3 (n = 51), we examined the relationship between spatial performance and the age at which peripubertal hormone replacement therapy was initiated in a sample of men with Isolated GnRH Deficiency. Across Studies 1–3, effect size estimates for the relationship between spatial performance and pubertal timing ranged from. −0.04 and −0.27, and spatial performance was unrelated to salivary testosterone in Study 2. In Study 4, we conducted two meta-analyses of Studies 1–3 and four previously published studies. The first meta-analysis was conducted on correlations between spatial performance and measures of the absolute age of pubertal timing, and the second replaced those correlations with correlations between spatial performance and measures of relative pubertal timing where available. Point estimates for correlations between pubertal timing and spatial cognition were −0.15 and −0.12 (both p < 0.001) in the first and second meta-analyses, respectively. These associations were robust to the exclusion of any individual study. Our results suggest that, for some aspects of neural development, sensitivity to gonadal hormones declines across puberty, with earlier pubertal hormone exposure predicting greater sex-typicality in psychological phenotypes in adulthood. These results shed light on the processes of behavioral and brain organization and have implications for the treatment of IGD and other conditions wherein pubertal timing is pharmacologically manipulated.
Quelle: Timing of peripubertal steroid exposure predicts visuospatial cognition in men: Evidence from three samples
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