Ceresini G, Marchini L, Fabbo A, Freddi M, Pasolini G, Reali N, Troglio G, Valenti G
Dipartimento di Biochimica, University of Parma, Italy.
Metabolism. 1997 Mar;46(3):282-6. doi: 10.1016/s0026-0495(97)90254-7.
The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems, anterior pituitary, and adrenal medulla. GAL is colocalized with corticotropin (ACTH) in the human pituitary and with epinephrine (E) and norepinephrine (NE) in chromaffin cells of the adrenal medulla. The function of GAL in peripheral tissues is not known, although the presence of the peptide in corticotrophs and the adrenal gland suggest that it participates in stress responses. In the present study, we investigated whether GAL is cosecreted with ACTH during activation of corticotrophs by an acute physical exercise test. Circulating levels of GAL and pituitary hormones were measured in healthy exercise-tested and control male subjects. Blood samples were collected during basal conditions, maximal power output (MPO), and the recovery period. Control subjects were sampled during the resting condition. The pituitary response to exercise was characterized by a significant increase in ACTH plasma levels (peak value 13.28 +/- 2.19 v 6.68 +/- 1.01 pmol/L, P < .05) and growth hormone (GH) serum levels (peak value, 14.53 +/- 5.59 v 0.29 +/- 0.1 microg/L, P < .02), with the peak in hormone levels detected 15 minutes after the end of exercise. No change in circulating prolactin (PRL) levels was detected. An expected significant increase in plasma levels of both E (peak value, 1,574.41 +/- 403.31 v 267.44 +/- 60.03 pmol/L, P < .01) and NE (peak value, 7,275.25 +/- 955.80 v 961.51 +/- 168.40 pmol/L, P < .01) was also observed. Plasma GAL levels were not affected by the acute exercise test, with the levels being comparable to baseline during the exercise test and the recovery phase. At any sample time, GAL values were comparable between exercise-tested and control subjects. These data show that despite the colocalization of GAL and ACTH within the same pituitary cells, the two peptides are not coreleased in response to stress resulting from acute physical exercise. Furthermore, pituitary GAL seems not to be involved in the stimulation of GH secretion in exercise-tested subjects. The results also indicate that GAL is not coreleased with E or NE in response to the exercise-induced stress condition.
神经肽甘丙肽（GAL）广泛分布于中枢和外周神经系统、垂体前叶及肾上腺髓质。在人垂体中，GAL与促肾上腺皮质激素（ACTH）共定位，在肾上腺髓质的嗜铬细胞中与肾上腺素（E）和去甲肾上腺素（NE）共定位。尽管该肽在促肾上腺皮质激素细胞和肾上腺中存在，提示其参与应激反应，但GAL在周围组织中的功能尚不清楚。在本研究中，我们调查了急性体育锻炼测试激活促肾上腺皮质激素细胞时，GAL是否与ACTH共同分泌。在健康的接受运动测试的男性受试者和对照男性受试者中测量了GAL和垂体激素水平。在基础状态、最大功率输出（MPO）及恢复期采集血样。对照受试者在静息状态下采样。运动对垂体的反应表现为ACTH血浆水平显著升高（峰值13.28±2.19对6.68±1.01 pmol/L，P<0.05）及生长激素（GH）血清水平显著升高（峰值14.53±5.59对0.29±0.1 μg/L，P<0.02），运动结束后15分钟检测到激素水平达到峰值。未检测到循环催乳素（PRL）水平变化。还观察到E（峰值1574.41±403.31对267.44±60.03 pmol/L，P<0.01）和NE（峰值7275.25±955.80对961.51±168.40 pmol/L，P<0.01）的血浆水平预期显著升高。急性运动测试未影响血浆GAL水平，在运动测试及恢复期其水平与基线相当。在任何采样时间，接受运动测试的受试者与对照受试者的GAL值相当。这些数据表明，尽管GAL和ACTH在同一垂体细胞中共定位，但这两种肽不会因急性体育锻炼产生的应激而共同释放。此外，垂体GAL似乎不参与接受运动测试的受试者中GH分泌的刺激。结果还表明，GAL不会因运动诱导的应激状态而与E或NE共同释放。
