Hidalgo-Díaz C, Castaño J P, López-Pedrera R, Malagón M M, García-Navarro S, Gracia-Navarro F
Department of Cell Biology, Faculty of Sciences, University of Córdoba, Spain.
Biol Reprod. 1998 Mar;58(3):678-85. doi: 10.1095/biolreprod58.3.678.
Substance P (SP) has been suggested to regulate gonadotroph function both directly and indirectly in different species. In pigs, the possible role of hypothalamic and pituitary SP in the control of LH release has not been examined. Here, we investigated SP effects on basal and GnRH-stimulated LH secretion by porcine gonadotrophs in vitro, in both static and dynamic culture systems. SP concentrations of 100 nM or above stimulated LH release from monolayer cultures without affecting intracellular LH content. In the same cultures, SP potentiated GnRH (10 nM)-stimulated LH release and reversed the GnRH-induced decrease of gonadotroph LH stores. The GnRH, but not the SP, effect was completely blocked by the potent GnRH-receptor antagonist antide. In superfused pituitary fragments, three successive pulses of SP or GnRH also stimulated LH release, yet the combined administration of both factors did not result in a synergistic stimulation. These results demonstrate that SP acts directly on porcine gonadotrophs to stimulate LH release, and to maintain the levels of hormonal stores, through a GnRH receptor-independent mechanism. Furthermore, our findings suggest that continuous exposure of gonadotrophs to SP would potentiate GnRH-stimulated LH secretion, thus supporting a possible role of SP as modulator of porcine gonadotroph function.
P物质（SP）已被认为在不同物种中可直接或间接调节促性腺激素细胞的功能。在猪中，下丘脑和垂体SP在控制促黄体生成素（LH）释放方面的潜在作用尚未得到研究。在此，我们在静态和动态培养系统中，研究了SP对体外培养的猪促性腺激素细胞基础分泌及GnRH刺激的LH分泌的影响。100 nM及以上浓度的SP刺激单层培养物中的LH释放，而不影响细胞内LH含量。在相同培养物中，SP增强GnRH（10 nM）刺激的LH释放，并逆转GnRH诱导的促性腺激素细胞LH储存量的减少。GnRH的作用被强效GnRH受体拮抗剂antide完全阻断，但SP的作用未被阻断。在灌流的垂体片段中，连续三个脉冲的SP或GnRH也刺激LH释放，但两种因子联合给药并未产生协同刺激作用。这些结果表明，SP通过一种不依赖GnRH受体的机制直接作用于猪促性腺激素细胞，刺激LH释放并维持激素储存水平。此外，我们的研究结果表明，促性腺激素细胞持续暴露于SP会增强GnRH刺激的LH分泌，从而支持SP作为猪促性腺激素细胞功能调节剂的可能作用。
