Ceresini G, Freddi M, Paccotti P, Valenti G, Merchenthaler I
Chair of Geriatrics, University of Parma, Italy.
J Clin Endocrinol Metab. 1997 Feb;82(2):607-10. doi: 10.1210/jcem.82.2.3779.
The neuropeptide galanin (GAL) has been shown to be located in the pituitary gland and to modulate the secretion of several pituitary hormones. In the human pituitary, GAL is almost exclusively located within corticotrophs. We examined whether GAL is secreted from corticotrophs in response to stimuli that induce ACTH release. Plasma levels of GAL and ACTH were evaluated in six healthy female subjects in the follicular phase of the menstrual cycle after the following treatments: 1) ovine CRH (oCRH) injection during saline (SAL) infusion, 2) oCRH injection during infusion of the arginine vasopressin analog desmopressin (DP), 3) SAL injection during DP infusion, and 4) SAL injection during SAL infusion. DP (4.3 ng/min.kg BW) or SAL was infused from 0-60 min. oCRH (1 microgram/kg BW) or SAL was administered by a 2-min injection at 5 min. The expected ACTH response to oCRH was enhanced by the concomitant DP administration (peak level, 10.39 +/- 1.12 vs. 21.37 +/- 3.43 pmol/L in SAL infusion plus oCRH injection vs. DP infusion plus oCRH injection, respectively; P < 0.05). The mean integrated ACTH response, expressed as the area under the curve, to SAL infusion plus oCRH injection vs. that to DP infusion plus oCRH injection was 288.23 +/- 61.94 vs. 699.70 +/- 91.80 pmol/L.60 min, respectively (P < 0.05). A slight, but not significant, increase was observed in ACTH values after DP infusion plus SAL injection compared to that after SAL infusion plus SAL injection challenge. Plasma GAL levels were highly variable. No changes in GAL levels were found concomitant to ACTH values in either experimental group. In fact, GAL levels were not significantly affected by either treatment. These data confirm that DP potentiates the ACTH response to CRH in humans. Furthermore, our results suggest that GAL is probably not cosecreted with ACTH in normal subjects. The possibility exists that GAL produced by corticotrophs exerts its action principally through a locally mediated paracrine or autocrine mechanism without being secreted into the bloodstream.
神经肽甘丙肽（GAL）已被证明存在于垂体中，并可调节多种垂体激素的分泌。在人类垂体中，GAL几乎仅存在于促肾上腺皮质激素细胞内。我们研究了促肾上腺皮质激素细胞是否会在诱导促肾上腺皮质激素（ACTH）释放的刺激下分泌GAL。在月经周期的卵泡期，对6名健康女性受试者进行以下处理后，评估其血浆中GAL和ACTH的水平：1）在输注生理盐水（SAL）期间注射羊促肾上腺皮质激素释放激素（oCRH）；2）在输注精氨酸加压素类似物去氨加压素（DP）期间注射oCRH；3）在输注DP期间注射SAL；4）在输注SAL期间注射SAL。从0至60分钟输注DP（4.3 ng/分钟·千克体重）或SAL。在5分钟时通过2分钟注射给予oCRH（1微克/千克体重）或SAL。同时给予DP可增强预期的oCRH诱导的ACTH反应（峰值水平，在SAL输注加oCRH注射组与DP输注加oCRH注射组中分别为10.39±1.12与21.37±3.43 pmol/L；P<0.05）。以曲线下面积表示的SAL输注加oCRH注射组与DP输注加oCRH注射组的平均整合ACTH反应分别为288.23±61.94与699.70±91.80 pmol/L·60分钟（P<0.05）。与SAL输注加SAL注射激发相比，DP输注加SAL注射后ACTH值有轻微但不显著的升高。血浆GAL水平高度可变。在任何一个实验组中，均未发现GAL水平随ACTH值的变化而改变。实际上，两种处理均未显著影响GAL水平。这些数据证实DP可增强人类对CRH的ACTH反应。此外，我们的结果表明，在正常受试者中GAL可能不会与ACTH共同分泌。存在一种可能性，即促肾上腺皮质激素细胞产生的GAL主要通过局部介导的旁分泌或自分泌机制发挥作用，而不会分泌到血液中。
