Capaldo Anna, Gay Flaminia, De Falco Maria, Virgilio Francesca, Laforgia Vincenza, Varano Lorenzo
Department of Biological Sciences, Section of Evolutive and Comparative Biology, University of Naples Federico II, Via Mezzocannone 8, 80134, Naples, Italy.
Anat Embryol (Berl). 2006 Nov;211(6):577-84. doi: 10.1007/s00429-006-0096-y. Epub 2006 Apr 22.
The response of the adrenal gland of Triturus carnifex to betamethasone administration was studied; the effects were evaluated by examination of the ultrastructural morphological features of the tissues as well as the serum levels of aldosterone, corticosterone, norepinephrine and epinephrine. In March and June, betamethasone significantly decreased the serum levels of aldosterone and corticosterone and the lipid droplet content in the steroidogenic cells. Moreover, betamethasone influenced the chromaffin tissue, enhancing in March (when the chromaffin cells produce norepinephrine and epinephrine in almost equal quantities) epinephrine serum levels and the numeric ratio between norepinephrine and epinephrine granules in the chromaffin cells. In June, (when the chromaffin cells contain almost exclusively norepinephrine granules) betamethasone administration raised norepinephrine serum levels, whereas a decrease in the numeric ratio between norepinephrine and epinephrine granules in the chromaffin cells was found. Finally, betamethasone administration did not evoke in June any increase in the mean number of epinephrine granules in the chromaffin cells and/or in epinephrine serum levels, as would be expected if phenyletanolamine-N-methyl transferase (PNMT) enzyme, converting norepinephrine into epinephrine, were activated by corticosteroids. The results of this study showed that betamethasone decreased aldosterone and corticosterone serum levels and enhanced catecholamine serum concentrations. Moreover, the present results suggest that a stimulatory role of glucocorticoids on PNMT enzyme may be ruled out.
研究了食用蝾螈肾上腺对倍他米松给药的反应；通过检查组织的超微结构形态特征以及醛固酮、皮质酮、去甲肾上腺素和肾上腺素的血清水平来评估其效果。在三月和六月，倍他米松显著降低了醛固酮和皮质酮的血清水平以及类固醇生成细胞中的脂滴含量。此外，倍他米松影响嗜铬组织，在三月（此时嗜铬细胞产生的去甲肾上腺素和肾上腺素数量几乎相等）提高了肾上腺素血清水平以及嗜铬细胞中去甲肾上腺素和肾上腺素颗粒之间的数量比。在六月（此时嗜铬细胞几乎只含有去甲肾上腺素颗粒），给予倍他米松提高了去甲肾上腺素血清水平，而在嗜铬细胞中发现去甲肾上腺素和肾上腺素颗粒之间数量比降低。最后，在六月给予倍他米松并没有像预期的那样引起嗜铬细胞中肾上腺素颗粒平均数量和/或肾上腺素血清水平的增加，如果将去甲肾上腺素转化为肾上腺素的苯乙醇胺 - N - 甲基转移酶（PNMT）被皮质类固醇激活，情况就会如此。这项研究的结果表明，倍他米松降低了醛固酮和皮质酮的血清水平并提高了儿茶酚胺血清浓度。此外，目前的结果表明可以排除糖皮质激素对PNMT酶的刺激作用。
