Giltay Erik J, Kho King H, Blansjaar Ben A, Verbeek Marcel M, Geurtz P Ben H, Geleijnse Johanna M, Gooren Louis J G
Geestelijke Gezondheidszorg Delfland, Institute of Mental Health, PO Box 5016, 2600 GA Delft, The Netherlands.
J Endocrinol. 2005 Oct;187(1):109-16. doi: 10.1677/joe.1.06307.
There is a close relationship between the brain and the endocrine system. The brain expresses receptors for sex steroids and is capable of metabolizing these hormones. We explored (1) sex differences in homovanillic acid (HVA), a metabolite of the neurotransmitter dopamine, and (2) the effects of cross-sex steroid administration in transsexual subjects. First, we compared plasma HVA levels between 38 male and 34 female healthy volunteers (not using hormone replacement therapy) of a mean age of 72 years (range 65-84 years). Secondly, we measured plasma HVA levels in 15 male-to-female transsexuals treated with 100 microg ethinyl estradiol/day and 100 mg cyproterone acetate/day for 4 months, and in 17 female-to-male transsexuals treated with testosterone esters (250 mg/2 weeks i.m. for 4 months). Plasma HVA levels were lower in elderly men than in elderly postmenopausal women (geometric mean 25.4 nmol/l (percentile (P)10 4.9; P90 69.8) vs 39.0 nmol/l (19.0; 76.1); P=0.027). In transsexuals before cross-sex hormone administration, genetic males also had lower plasma levels of HVA than genetic females (geometric mean 14.8 nmol/l (P10 7.0; P90 35.0) vs 34.3 nmol/l (21.8; 61.4); P<0.001). Cross-sex hormone administration did not affect plasma HVA in either group (P>0.5). The pretreatment sex difference in plasma HVA was unaffected after 4 months of cross-sex hormone administration (P=0.003). The sex difference in plasma HVA was not reversed by cross-sex hormone administration in transsexuals, and was also preserved in elderly subjects. This indicated that differences in dopamine gene expression were largely unaffected by exposure to sex hormone levels in adulthood, but must rather be explained by a sex difference in genetic factors or by the organizing effects of sex hormones during early development.
大脑与内分泌系统之间存在着密切的关系。大脑表达性类固醇受体，并能够代谢这些激素。我们探究了：（1）神经递质多巴胺的代谢产物高香草酸（HVA）的性别差异；（2）在变性者中给予跨性别类固醇的影响。首先，我们比较了38名男性和34名女性健康志愿者（未使用激素替代疗法）的血浆HVA水平，这些志愿者的平均年龄为72岁（年龄范围65 - 84岁）。其次，我们测量了15名接受每天100微克乙炔雌二醇和100毫克醋酸环丙孕酮治疗4个月的男变女变性者，以及17名接受睾酮酯（每2周肌肉注射250毫克，共4个月）治疗的女变男变性者的血浆HVA水平。老年男性的血浆HVA水平低于老年绝经后女性（几何平均数分别为25.4纳摩尔/升（第10百分位数（P）4.9；第90百分位数69.8）和39.0纳摩尔/升（19.0；76.1）；P = 0.027）。在给予跨性别激素之前，基因男性的血浆HVA水平也低于基因女性（几何平均数分别为14.8纳摩尔/升（P10 7.0；P90 35.0）和34.3纳摩尔/升（21.8；61.4）；P < 0.001）。给予跨性别激素对两组的血浆HVA均无影响（P > 0.5）。给予跨性别激素4个月后，血浆HVA的预处理性别差异未受影响（P = 0.003）。变性者中血浆HVA的性别差异不会因给予跨性别激素而逆转，在老年受试者中也同样存在。这表明多巴胺基因表达的差异在很大程度上不受成年期性激素水平暴露的影响，而更可能是由遗传因素的性别差异或早期发育中性激素的组织效应来解释。
