Lactic acid does not directly activate hypothalamic-pituitary corticotroph function.
Lactic acid does not directly activate hypothalamic-pituitary corticotroph function.
复制标题
乳酸不直接激活下丘脑-垂体促肾上腺皮质激素功能。
DOI：
10.1046/j.1525-1373.1999.d01-16.x
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Mueller,GP
中科院分区：
文献类型：
--
作者：
Petrides,JS;Deuster,PA;Mueller,GP
在剧烈运动中，代谢产物在调节下丘脑-垂体-肾上腺(HPA)轴中所起的作用尚属推测。这项研究考察了无氧运动的主要代谢物乳酸对下丘脑-垂体功能的直接影响程度。具体地说，用生理水平的乳酸(0.5×10β3M至5×10−2M)或乳酸与促肾上腺皮质激素释放因子：促肾上腺皮质激素释放激素、精氨酸加压素、去甲肾上腺素和/或肾上腺素联合作用，测量了At-20(D-16)小鼠促肾上腺皮质激素肿瘤细胞的促肾上腺皮质激素分泌。用ATT-20细胞培养的结果表明，在大鼠垂体前叶的原代培养中具有代表性。乳酸不改变AtT-20细胞在急慢性条件下自发释放β-内啡肽。虽然促肾上腺皮质激素释放激素、去甲肾上腺素和肾上腺素引起β-内啡肽释放的显著增加，但乳酸与这些促分泌剂的结合并不改变它们的作用。同样，乳酸不能改变原代培养的大鼠垂体β-内啡肽的基础或刺激释放。然而，在大鼠下丘脑组织块中加入乳酸(3×103M)后，自发的CRH释放确实有轻微但显著的减少，这表明乳酸可能促进运动后基础分泌的恢复。目前的研究结果表明，生理浓度的乳酸对促肾上腺皮质激素的分泌没有影响，无论是单独的还是与其他垂体促分泌剂联合使用。虽然乳酸在下丘脑中的生理作用是可能的，但目前的发现表明，乳酸是CRH释放的抑制剂。因此，在剧烈运动后HPA轴的深刻激活中，乳酸似乎并不起直接作用。
The role that metabolic products play in regulating the hypothalamic‐pituitary‐adrenal (HPA) axis during strenuous exercise is speculative. This investigation examined the extent to which lactic acid, a major metabolite of anaerobic exercise, directly affects hypothalamic‐pituitary function. Specifically, β‐endorphin secretion was measured from AtT‐20 (D‐16) mouse corticotroph tumor cells treated either acutely (15 min − 180 min) or chronically (1 day − 3 day) with physiologic levels of lactate (0.5 × 10−3Mto 5 × 10−2M) or lactate in combination with the corticotroph releasing factors: corticotroph releasing hormone (CRH), arginine vasopressin (AVP), norepinephrine and/or epinephrine. Findings with AtT‐20 cell cultures were shown to be representative of responses in primary cultures of rat anterior pituitary. Lactic acid did not alter the spontaneous release of β‐endorphin by AtT‐20 cells under either acute or chronic conditions. While CRH, norepinephrine, and epinephrine evoked significant increases in β‐endorphin release, lactate, in combination with these secretagogues did not alter their effects. Similarly, lactic acid failed to alter basal or stimulated release of β‐endorphin by primary cultures of rat anterior pituitary. The addition of lactate (3 × 103M) to rat hypothalamic explants did, however, produce a modest but significant reduction in spontaneous CRH release, suggesting that lactate may facilitate the return to basal secretion following exercise. The present findings show that physiologic concentrations of lactate have no effect, either alone or in combination with other pituitary secretagogues, on corticotroph secretion. Whereas a physiologic action for lactate within the hypothalamus is possible, the present findings indicate that lactate is an inhibitor of CRH release. Thus, lactate does not appear to play a direct role in the profound activation of the HPA axis that occurs in response to strenuous exercise.