Sympathoadrenal activity in fasting pregnant rats. Dissociation of adrenal medullary and sympathetic nervous system responses.
Sympathoadrenal activity in fasting pregnant rats. Dissociation of adrenal medullary and sympathetic nervous system responses.
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禁食怀孕大鼠的交感肾上腺活动。
DOI：
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发表时间：
1979
影响因子：
15.9
通讯作者：
Lewis Landsberg
中科院分区：
文献类型：
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作者：
James B. Young;Lewis Landsberg
妊娠大鼠和非妊娠大鼠禁食时尿儿茶酚胺排泄模式不同，这表明妊娠改变了对禁食的交感肾上腺反应。在禁食的非妊娠动物中，尿去甲肾上腺素（NE）排泄减少，肾上腺素（E）排泄保持不变，而两种儿茶酚胺的排泄随着再喂养而显著升高。与此相反，禁食妊娠晚期大鼠表现出420%的尿E和尿NE增加345%，升高下降与再喂养。对禁食妊娠大鼠交感肾上腺活性的具体评价表明，肾上腺髓质受到刺激，交感神经受到抑制。在禁食的孕晚期大鼠中，与对侧失神经支配的肾上腺相比，受神经支配的肾上腺中E的肾上腺含量低37%，这表明存在神经介导的肾上腺髓质激活。肾上腺切除术完全取消了禁食引起的尿E和NE的上升在怀孕的大鼠。2-脱氧-D-葡萄糖的研究表明，肾上腺髓质的刺激是由妊娠大鼠禁食3天后出现的低血糖引起的（血浆葡萄糖36.7 mg/dl）。通过测定心脏中[（3）H] NE的周转率，发现禁食妊娠大鼠的交感神经系统活动降低，尽管存在低血糖，这一反应与禁食非妊娠动物（血糖维持在50 mg/dl以上）相似。2天禁食妊娠大鼠的NE转换率计算值比进食妊娠动物低44%（分别为17.6 +/-1.3和31.3 +/-1.8 ng NE/心脏/h）。因此，肾上腺髓质和交感神经系统的反应在禁食妊娠大鼠似乎是分离的，这表明，饮食诱导的交感神经活性的变化和刺激肾上腺髓质低血糖可能是独立的调节。
The pattern of urinary catecholamine excretion in fasting differs in pregnant and nonpregnant rats, which suggests that the sympathoadrenal response to fasting is altered by pregnancy. In fasting nonpregnant animals, urinary norepinephrine (NE) excretion decreases and epinephrine (E) excretion remains unchanged, whereas the excretion of both catecholamines rises significantly with refeeding. In contrast, fasting third-trimester pregnant rats exhibit a 420% increase in urinary E and a 345% increase in urinary NE, elevations which fall with refeeding. Specific evaluation of sympathoadrenal activity in fasting pregnant rats reveals stimulation of the adrenal medulla and suppression of sympathetic nerves. In fasting third-trimester rats the adrenal content of E is 37% lower in innervated adrenals as compared with contralateral denervated glands, which indicates the presence of neurally-mediated adrenal medullary activation. Adrenalectomy completely abolishes the fasting-induced rise in urinary E and NE in pregnant rats. Studies with 2-deoxy-D-glucose suggest that stimulation of the adrenal medulla results from hypoglycemia, which is present after 3 d of fasting in pregnant rats (plasma glucose 36.7 mg/dl). Sympathetic nervous system activity, as measured by [(3)H]NE turnover in the heart, decreases in fasting pregnant rats despite hypoglycemia, a response similar to that seen in fasting nonpregnant animals where plasma glucose is maintained above 50 mg/dl. The calculated NE turnover rate is 44% lower in 2-d fasted pregnant rats than in fed pregnant animals (17.6 +/- 1.3 vs. 31.3 +/- 1.8 ng NE/heart per h, respectively). Thus adrenal medullary and sympathetic nervous system responses in fasting pregnant rats appear to be dissociated, which suggests that diet-induced changes in sympathetic activity and stimulation of the adrenal medulla by hypoglycemia may be independently regulated.