Shaw G, Jorgensen G I, Tweedale R, Tennison M, Waters M J
J Endocrinol. 1985 Dec;107(3):429-36. doi: 10.1677/joe.0.1070429.
Adult Merino ewes were infused via the jugular vein with either saline (n = 5) or epidermal growth factor (EGF) (4.2 micrograms/kg per h, n = 6) for 24 h in either the luteal phase or the follicular phase of the oestrous cycle and reproductive function was examined. Infusion of EGF during the luteal phase caused no detectable change in plasma progesterone or prolactin concentrations over a 7-day period compared with the controls. Infusion of EGF during the follicular phase suppressed the oestrous rise in plasma oestradiol. Luteinizing hormone pulse amplitude was increased and pulse frequency was decreased by the end of the infusion. All control ewes had a pro-oestrous LH surge and mated, but the LH surge and oestrus were prevented by EGF infusion. Nevertheless, plasma progesterone levels rose subsequently in the EGF-infused ewes in parallel with the control ewes, suggesting that the preovulatory follicle had luteinized. Both LH and FSH rose over the 7 days after EGF infusion to levels similar to those in ovariectomized ewes. Thus EGF appears to inhibit follicular oestradiol production, although it does not affect luteal progesterone production or follicular luteinization. We suggest that the alteration in gonadotrophin secretion patterns results from a disturbance of feedback mechanisms between the ovary and the hypothalamopituitary axis, although a direct effect in the brain or the pituitary gland cannot yet be excluded.
在发情周期的黄体期或卵泡期，通过颈静脉向成年美利奴母羊输注生理盐水（n = 5）或表皮生长因子（EGF）（4.2微克/千克每小时，n = 6），持续24小时，然后检查生殖功能。与对照组相比，在黄体期输注EGF在7天内未引起血浆孕酮或催乳素浓度的可检测变化。在卵泡期输注EGF抑制了血浆雌二醇的发情期升高。输注结束时，促黄体生成素脉冲幅度增加，脉冲频率降低。所有对照母羊都有发情前期促黄体生成素高峰并交配，但EGF输注阻止了促黄体生成素高峰和发情。然而，输注EGF的母羊血浆孕酮水平随后与对照母羊平行上升，表明排卵前卵泡已黄体化。在EGF输注后的7天内，促黄体生成素和促卵泡生成素均升高至与去卵巢母羊相似的水平。因此，EGF似乎抑制卵泡雌二醇的产生，尽管它不影响黄体孕酮的产生或卵泡黄体化。我们认为，促性腺激素分泌模式的改变是由于卵巢与下丘脑 - 垂体轴之间反馈机制的紊乱所致，尽管尚未排除在大脑或垂体中的直接作用。
