Decourt C, Anger K, Robert V, Lomet D, Bartzen-Sprauer J, Caraty A, Dufourny L, Anderson G, Beltramo M
Unité Mixte de Recherche Physiologie de la Reproduction et des Comportements (Institut National de la Recherche Agronomique, Unité Mixte de Recherche 85; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Université François Rabelais Tours, IFCE) (C.D., K.A., V.R., D.L., J.B.-S., A.C., L.D., M.B.), F-37380 Nouzilly, France; and Centre for Neuroendocrinology and Department of Anatomy (G.A.), University of Otago School of Medical Sciences, Dunedin 9054, New Zealand.
Endocrinology. 2016 Apr;157(4):1566-75. doi: 10.1210/en.2015-1854. Epub 2016 Feb 10.
The neuropeptide RFamide-related peptide 3 (RFRP-3) has been implicated in the control of gonadotropin secretion in both birds and mammals. However, in mammals, depending on species, sex and photoperiod, inhibitory, excitatory, or no effect of RFRP-3 on the plasma concentration of LH has been reported. In the ewe, treatment with RFRP-3 either reduced LH concentration or had no effect, and treatment with an RFRP-3 receptor antagonist (ie, RF9) resulted in increased concentration of plasma LH. To clarify these conflicting results in the present study, a set of experiments was performed in ewes. Multiple iv injections of RFRP-3 (6 × 50 μg) in ovariectomized ewes had no effect on plasma LH pulsatility. In intact ewes a bolus injection (500 μg) or an injection (250, 500, or 1000 μg) followed by a 4-hour perfusion (250, 500, or 1000 μg · h(-1)) of RFRP-3 had no effect on the LH pulse induced by kisspeptin (6.5 μg). In ovariectomized, estrogen-replaced ewes, the LH surge induced by estradiol benzoate was not modified by a 24-hour perfusion of RFRP-3 (500 μg h(-1)). Finally, although treatment with RF9 induced a robust release of LH, treatment with a more selective RFRP-3 receptor antagonist, GJ14, resulted in no evident increase of LH. In contrast to the inhibitory effect previously suggested, our data are more consistent with the concept that RFRP-3 has no direct effect on LH secretion in ewes and that RF9 effect on LH release is likely not RFRP-3 receptor mediated. Hence, RFRP-3 probably has a minor role on the control of LH secretion in the ewe.
神经肽RF酰胺相关肽3（RFRP - 3）已被证实参与鸟类和哺乳动物促性腺激素分泌的调控。然而，在哺乳动物中，根据物种、性别和光照周期的不同，RFRP - 3对促黄体生成素（LH）血浆浓度的影响报道不一，有抑制作用、兴奋作用或无作用。在母羊中，用RFRP - 3处理要么降低LH浓度，要么无影响，而用RFRP - 3受体拮抗剂（即RF9）处理则导致血浆LH浓度升高。为了阐明本研究中这些相互矛盾的结果，我们在母羊身上进行了一系列实验。对去卵巢母羊多次静脉注射RFRP - 3（6×50μg）对血浆LH脉冲性没有影响。在未切除卵巢的母羊中，一次推注（500μg）或一次注射（250、500或1000μg）后接着4小时灌注（250、500或1000μg·h⁻¹）RFRP - 3对亲吻素（6.5μg）诱导的LH脉冲没有影响。在去卵巢并用雌激素替代的母羊中，苯甲酸雌二醇诱导的LH峰不受24小时灌注RFRP - 3（500μg·h⁻¹）的影响。最后，虽然用RF9处理可诱导LH大量释放，但用更具选择性的RFRP - 3受体拮抗剂GJ14处理并未使LH明显升高。与之前认为的抑制作用相反，我们的数据更符合这样的概念，即RFRP - 3对母羊LH分泌没有直接影响，且RF9对LH释放的作用可能不是由RFRP - 3受体介导的。因此，RFRP - 3可能在母羊LH分泌调控中起次要作用。
