Carroll R S, Erskine M S, Baum M J
Department of Biology, Boston University, Massachusetts 02215.
Endocrinology. 1987 Oct;121(4):1349-59. doi: 10.1210/endo-121-4-1349.
Sex differences in the pulsatile secretion of LH were examined in male and female ferrets after mating. Female ferrets which were either gonadally intact and in estrus or gonadectomized and maintained on a pulsed regimen of daily estradiol (E2) injections exhibited a prolonged rise in plasma LH, characterized by an elevation in mean LH levels and an increase in the number of LH pulses after receiving an intromission from a stud male. By contrast, no such increase in LH secretion occurred in males which achieved an intromission with a female, regardless of whether they were gonadally intact and in breeding condition or gonadectomized and given pulsed estrogen. In fact, intact breeding males which achieved an intromission had significantly fewer LH pulses 1-5 h later than unmated males bled serially over the same time period. This decrease in LH pulse frequency was followed by a significant rise in mean plasma levels of androgen 5-12 h later. When a sexually dimorphic LH response to intromission was observed in gonadectomized E2-treated ferrets, we asked whether this could reflect a sex difference in pituitary responsiveness to the endogenous release of GnRH. Thus, plasma LH levels were measured in gonadectomized and gonadectomized E2-treated ferrets for 2 h after iv injection of GnRH. In the absence of gonadal steroids, ferrets exhibited a sex-specific difference in LH responsiveness to GnRH; however, no sex difference was apparent under the influence of E2. These findings demonstrate that ferrets' sexually dimorphic LH responses to intromission probably reflect a sex difference in the processing of somatosensory inputs from the genitalia or in the neural control of GnRH release into the pituitary portal vessels.
在交配后的雄性和雌性雪貂中研究了促黄体生成素（LH）脉冲式分泌的性别差异。性腺完整且处于发情期的雌性雪貂，或性腺切除并每日注射脉冲式雌二醇（E2）的雌性雪貂，在接受种公貂的插入动作后，血浆LH出现持续升高，其特征为平均LH水平升高以及LH脉冲数量增加。相比之下，与雌性雪貂成功完成插入动作的雄性雪貂，无论其性腺是否完整且处于繁殖状态，还是性腺切除并给予脉冲式雌激素，LH分泌均未出现此类增加。事实上，成功完成插入动作的性腺完整的繁殖雄性雪貂，在1 - 5小时后LH脉冲数量比在同一时间段内连续采血的未交配雄性雪貂显著减少。LH脉冲频率的这种下降之后，雄激素的平均血浆水平在5 - 12小时后显著升高。当在性腺切除并经E2处理的雪貂中观察到对插入动作有性别二态性的LH反应时，我们询问这是否可能反映了垂体对GnRH内源性释放反应的性别差异。因此，在静脉注射GnRH后2小时，测量性腺切除和性腺切除并经E2处理的雪貂的血浆LH水平。在没有性腺类固醇的情况下，雪貂对GnRH的LH反应表现出性别特异性差异；然而，在E2的影响下未观察到性别差异。这些发现表明，雪貂对插入动作的性别二态性LH反应可能反映了来自生殖器的躯体感觉输入处理过程中的性别差异，或者是GnRH释放到垂体门脉血管的神经控制方面的性别差异。
