Weaning and the developmental changes in follicle-stimulating hormone, pituitary adenylate cyclase-activating polypeptide, and inhibin B in the male rat.
Weaning and the developmental changes in follicle-stimulating hormone, pituitary adenylate cyclase-activating polypeptide, and inhibin B in the male rat.
复制标题
雄性大鼠断奶及促卵泡激素、垂体腺苷酸环化酶激活多肽和抑制素 B 的发育变化。
DOI：
10.1095/biolreprod.107.065466
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发表时间：
2008
影响因子：
3.6
通讯作者：
Winters,StephenJ
中科院分区：
文献类型：
--
作者：
MooreJr,JosephP;Winters,StephenJ
雄性大鼠生后第20天起，垂体Fshb浓度显著且选择性地升高。为了评估可能导致FSH升高的因素，我们调整了断奶时间，通常也是在第20天。雄性幼鼠只通过哺乳获得营养，并比通常在动物设施中进行的断奶(第20天)更早(第17天)或更晚(第23天)断奶。在17日龄至29日龄期间，血清黄体生成素(1.4倍)和卵泡刺激素(2.4倍)水平显著升高，垂体Lhb(5.4倍)、FSHB(21.3倍)和抑制素βB(Inhbb，2.26倍)mRNAs表达显著增加，睾丸Inhbb(10倍)mRNAs表达显著增加。同时，血清抑制素B水平(1.8倍)、垂体腺苷环化酶激活多肽(ADCYAP1，4.2倍)、总卵泡抑素(Fst，3.5倍)和Fstisoform 288(5.6倍)mRNAs，以及睾丸抑制素βA(8.2倍)mRNAs表达显著下降。早期断奶可显着提高血清FSH水平，但不显着提高促黄体生成素水平；增加垂体促性腺激素释放激素受体(GnRH)mRNAs的表达，但不显着提高Lhb水平。早期断奶也显著降低血清抑制素B，但增加睾丸Inhbbb亚单位的表达。早期断奶还导致垂体腺样囊泡蛋白1的表达较对照组提前下降。断奶后立即，生长显著加速，断奶时间对循环瘦素水平产生显著和不同的影响，与FSH产生的指标无关。根据这些观察，我们提出了一个新的假设，即断奶后信号循环抑制素B水平下降的生长速度增加，以及垂体Adcyap1和随之而来的Fst表达减少，这些事件共同通过增加垂体激活素信号来促进Fshband Gnrh抑制的增加。
PituitaryFshbconcentrations increase markedly and selectively beginning on Postnatal Day 20 in the male rat. To evaluate the factors potentially responsible for this rise in FSH, we adjusted the time of weaning, which is generally also on Day 20. Male rat pups were provided nutrients by suckling only and were weaned to laboratory chow earlier (Day 17) or later (Day 23) than normally performed in animal facilities (Day 20). Between ages 17 and 29 days, significant increases were seen in serum LH (1.4-fold) and FSH (2.4-fold) levels; pituitary expression ofLhb(5.4-fold),Fshb(21.3-fold), and inhibin beta B (Inhbb, 2.26-fold) mRNAs; and testicular expression ofInhbb(10-fold) mRNA. Concurrently, significant decreases occurred in serum inhibin B levels (1.8-fold); pituitary adenylate cyclase-activating polypeptide (Adcyap1, 4.2-fold), total follistatin (Fst, 3.5-fold), andFstisoform 288 (5.6-fold) mRNAs; and testicular expression of inhibin beta A (8.2-fold) mRNA. Early weaning significantly increased serum FSH but not LH and increased pituitary expression ofFshband GnRH receptor (Gnrhr) mRNAs but notLhb. Early weaning also significantly decreased serum inhibin B but increased testicular expression of theInhbbsubunit. Early weaning also caused pituitary expression ofFstandAdcyap1to decline earlier than in the control group. Immediately after weaning, growth accelerated substantially, and the time of weaning produced significant and differential effects on circulating leptin levels that were not related to indices of FSH production. From these observations, we propose the novel hypothesis that the increase in growth rate subsequent to weaning signals circulating inhibin B levels to fall and pituitaryAdcyap1and consequentlyFstexpression to decrease, and that these events together facilitate the rise inFshbandGnrhrexpression by increasing pituitary activin signaling.