Coquelin A
Department of Cell Biology and Anatomy, Texas Tech University Health Sciences Center, Lubbock 79430.
Biol Reprod. 1991 Sep;45(3):424-31. doi: 10.1095/biolreprod45.3.424.
This experiment was designed to determine whether the reflexive LH pulses induced in male mice by exposure to a female are dependent upon the presence of the testes. B6D2F1 males were studied because, unlike most males, these hybrids remain sexually active indefinitely after castration, demonstrating that they still recognize females and are sexually arousable. We reasoned that if LH reflexes occur independently of the testes, then exposing castrated B6D2F1 males to a female should elicit a pulse. We observed female-induced pulses in 67% of intact, naive males and 80% of intact, sexually experienced males, but they were absent in castrated, sexually experienced males. Spontaneous pulses were too frequent in castrated, naive males to distinguish potential LH reflexes. Thus, the induction of LH reflexes depends upon the presence of the testes in these hybrid males. Secondarily we found more frequent spontaneous pulses in sexually naive than in experienced mice regardless of their gonadal status. These unexpected results imply that long-term mating activity slows the pace of spontaneous LH pulses in these hybrids. Considered together, the differential effects of the testes and sexual experience on both types of LH pulses suggest that two distinct pulse-generating mechanisms exist in male mice.
本实验旨在确定雄性小鼠接触雌性后诱导产生的反射性促黄体激素（LH）脉冲是否依赖于睾丸的存在。选用B6D2F1雄性小鼠进行研究，因为与大多数雄性小鼠不同，这些杂种小鼠在阉割后仍能无限期地保持性活跃，这表明它们仍能识别雌性且具有性唤起能力。我们推断，如果LH反射的发生独立于睾丸，那么将阉割后的B6D2F1雄性小鼠暴露于雌性小鼠应该会引发脉冲。我们观察到，67%的未交配过的完整雄性小鼠和80%的有过性经验的完整雄性小鼠出现了由雌性诱导的脉冲，但在有过性经验的阉割雄性小鼠中未出现。在未交配过的阉割雄性小鼠中，自发脉冲过于频繁，无法区分潜在的LH反射。因此，在这些杂种雄性小鼠中，LH反射的诱导依赖于睾丸的存在。其次，我们发现，无论性腺状态如何，未交配过的小鼠比有过性经验的小鼠自发脉冲更频繁。这些意外结果表明，长期的交配活动会减缓这些杂种小鼠自发LH脉冲的频率。综合来看，睾丸和性经验对两种类型LH脉冲的不同影响表明，雄性小鼠存在两种不同的脉冲产生机制。
