Barthold J S, Mahler H R, Sziszak T J, Newton B W
Department of Urology, University of Arkansas for Medical Sciences, Little Rock, USA.
J Urol. 1996 Aug;156(2 Pt 2):767-71. doi: 10.1097/00005392-199608001-00057.
The sexually dimorphic cremaster nucleus contains motoneurons that project via the genitofemoral nerve and theoretically direct androgen dependent testicular descent. The effects of flutamide on descent and masculinization of the cremaster nucleus were studied in the rat and pig.
Flutamide was given to pregnant rats and pigs on days 16 to 22 and 65 to 113 of gestation, respectively. Tissues were perfused and examined at birth (pigs) or at age 30 days (rats). Spinal cords were removed, sectioned and immunohistochemically stained for serotonin (rats) or substance P (pigs) to demarcate the position of the cremaster nucleus and allow the determination of cremaster motoneuron number.
After exposure to flutamide testes were undescended in 6 of 9 rats and 7 of 10 pigs. Cremaster motoneuron number per nucleus were 288 +/- 22 in control versus 250 +/- 27 in flutamide treated rats, and 165 +/- 28 in control versus 148 +/- 24 in flutamide treated pigs. The decrease in motoneuron number by flutamide was significant in both species (p < 0.02) but it did not approach the levels in female rats (93 +/- 11) and pigs (57 +/- 12). Cremaster motoneuron number did not correlate with testicular position. Porcine undescended testes were associated with a significant increase in mean gubernacular volume.
Unlike other sexually dimorphic spinal cord nuclei masculinization of the cremaster nucleus appears to be largely androgen independent and it does not correlate with ipsilateral testicular descent. These data suggest that androgens do not mediate descent of the testes via the efferent limb of the genitofemoral nerve.
具有性别差异的提睾肌核含有运动神经元，这些运动神经元通过生殖股神经投射，理论上指导雄激素依赖的睾丸下降。在大鼠和猪中研究了氟他胺对提睾肌核下降和雄性化的影响。
分别在妊娠第16至22天和65至113天给怀孕的大鼠和猪给予氟他胺。在出生时（猪）或30日龄（大鼠）对组织进行灌注和检查。取出脊髓，切片并进行免疫组织化学染色以检测5-羟色胺（大鼠）或P物质（猪），以划定提睾肌核的位置并确定提睾肌运动神经元数量。
暴露于氟他胺后，9只大鼠中有6只和10头猪中有7只睾丸未下降。每核提睾肌运动神经元数量在对照组大鼠中为288±22，在氟他胺处理组大鼠中为250±27；在对照组猪中为165±28，在氟他胺处理组猪中为148±24。氟他胺导致的运动神经元数量减少在两个物种中均具有统计学意义（p<0.02），但未达到雌性大鼠（93±11）和猪（57±12）的水平。提睾肌运动神经元数量与睾丸位置无关。猪未降睾丸与平均引带体积显著增加有关。
与其他具有性别差异的脊髓核不同，提睾肌核的雄性化似乎在很大程度上不依赖雄激素，且与同侧睾丸下降无关。这些数据表明，雄激素不通过生殖股神经的传出支介导睾丸下降。
