Mondain-Monval M, Farstad W, Smith A J, Roger M, Lahlou N
Fondation de Recherche en Hormonologie, Fresnes, France.
J Reprod Fertil Suppl. 1993;47:47-56.
The blue fox is a monestrous seasonal breeder with a pro-oestrus and oestrus lasting several days and a prolonged luteal phase in non-pregnant as well as pregnant vixens. Ovulation occurs 2 days after the preovulatory luteinizing hormone (LH) peak at the onset of oestrus; oocytes are ovulated as primary oocytes and maturation is completed 2-3 days later. Fertilization is possible during all stages of oocyte maturation until degeneration of oocytes 5 or 6 days after the LH peak. In this study, changes in plasma concentrations of follicle-stimulating hormone (FSH) and immunoreactive inhibin (iINH) and their relationships with LH, oestradiol, androstenedione, testosterone and progesterone secretion and with the periovulatory events, were determined throughout the reproductive cycle of 14 vixens. In late anoestrus and pro-oestrus, FSH and iINH were inversely related to each other (r = -0.84, P < 0.001); whereas FSH concentrations declined to reach low values within the 5 days preceding the LH peak, iINH secretion increased, as did that of oestradiol and androgens. Thereafter, iINH and steroid concentrations with the exception of progesterone reached maximal values at the time of the LH and FSH peaks and decreased within the following 2-3 days in the early luteal phase. Progesterone started to increase simultaneously with the LH peak, and when oocyte maturation was completed (around day 4), progesterone concentrations were increasing, while those of other hormones were low. A postovulatory release of FSH was detected between days 6 and 10; it preceded the rise in iINH, which began on day 8 when concentrations of progesterone were already high and those of oestradiol and LH were low. Progesterone and iINH were positively correlated over the period day 6 to day 49 (r = 0.62, P < 0.01). These results indicate that, in the blue fox, iINH is secreted by the preovulatory follicle and the corpus luteum; that during pro-oestrus, iINH may act in synergy with oestradiol to reduce the secretion of FSH and that after the LH peak the decrease of iINH and oestradiol concentrations may be responsible for the postovulatory release of FSH, which in turn causes an increase in iINH, possibly secreted by the corpus luteum and, as a result, FSH secretion is suppressed.
蓝狐是季节性单次发情的动物，其发情前期和发情期持续数天，未怀孕和怀孕母狐的黄体期都较长。发情开始时，排卵发生在促黄体生成素（LH）排卵前高峰后的2天；卵母细胞以初级卵母细胞形式排出，2 - 3天后完成成熟。在卵母细胞成熟的所有阶段都可能受精，直到LH高峰后5或6天卵母细胞退化。在本研究中，测定了14只母狐整个生殖周期中促卵泡激素（FSH）和免疫反应性抑制素（iINH）的血浆浓度变化，以及它们与LH、雌二醇、雄烯二酮、睾酮和孕酮分泌的关系，以及与排卵前后事件的关系。在发情后期和发情前期，FSH和iINH呈负相关（r = -0.84，P < 0.001）；在LH高峰前5天内，FSH浓度下降至低值，而iINH分泌增加，雌二醇和雄激素的分泌也增加。此后，除孕酮外，iINH和类固醇浓度在LH和FSH高峰时达到最大值，并在黄体期早期的接下来2 - 3天内下降。孕酮在LH高峰时同时开始增加，当卵母细胞成熟完成时（约第4天），孕酮浓度在上升，而其他激素浓度较低。在第6天至第10天之间检测到排卵后FSH的释放；它先于iINH的升高，iINH在第8天开始升高，此时孕酮浓度已经很高，而雌二醇和LH浓度较低。在第6天至第49天期间，孕酮和iINH呈正相关（r = 0.62，P < 0.01）。这些结果表明，在蓝狐中，iINH由排卵前卵泡和黄体分泌；在发情前期，iINH可能与雌二醇协同作用以减少FSH的分泌，并且在LH高峰后，iINH和雌二醇浓度的下降可能是排卵后FSH释放的原因，这反过来又导致iINH增加，可能由黄体分泌，结果FSH分泌受到抑制。
