Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, 2 Medical Center Drive, Stratford, NJ 08084, USA; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Rutgers University, 683 Hoes Lane West, Piscataway, NJ 08854, USA.
Department of Biology and Center for Computational and Integrative Biology, Rutgers University, 311 North Fifth Street, Camden, NJ 08102, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2021 Dec;262:111061. doi: 10.1016/j.cbpa.2021.111061. Epub 2021 Aug 28.
The present study examined how food availability interacts with age to modulate lizard adrenal steroidogenic function at the cellular level. Adult male and juvenile male and female Eastern Fence Lizards (Sceloporus undulatus) underwent a period of food deprivation with or without a shorter re-feeding period. Lizards maintained on a full feeding regimen served as the controls. Across the feeding regimens, plasma corticosterone of adult lizards was unchanged whereas that of food-deprived juvenile lizards was increased nearly 7 times and this increase was normalized by a short re-feeding period. Freshly dispersed adrenocortical cells derived from these lizards were incubated with ACTH and the production of selected steroids was measured by highly specific radioimmunoassay. Net maximal steroid rates of juvenile cells were 161% greater than those of adult cells. Adult and juvenile progesterone rates were consistently suppressed by food deprivation (by nearly 48%) and were normalized by a re-feeding period, whereas divergent effects were seen with corticosterone and aldosterone rates. Food deprivation suppressed corticosterone rates of adult cells by 43% but not those of juvenile cells. In a reciprocal manner, food deprivation had no significant effect on aldosterone rates of adult cells, but it suppressed those of juvenile cells by 52%. A short re-feeding period normalized most rates in both adult and juvenile cells and further augmented the adult aldosterone rate by 54%. The effect of the feeding regimens on ACTH sensitivity varied with life stage and with steroid. The overall sensitivity of adult cells to ACTH was nearly three times that of juvenile cells. Collectively, the data presented here and data from previous work indicate that food restriction/deprivation in Sceloporus lizard species causes a functional remodeling of the adrenocortical tissue. Furthermore, life stage adds more complexity to this remodeling.
本研究旨在探讨食物可利用性如何与年龄相互作用，在细胞水平上调节蜥蜴肾上腺类固醇生成功能。成年雄性和幼年雄性和雌性东部栅栏蜥蜴（Sceloporus undulatus）经历了禁食期和禁食后短暂的再喂食期。维持正常喂食方案的蜥蜴作为对照。在整个喂食方案中，成年蜥蜴的血浆皮质酮保持不变，而禁食的幼年蜥蜴的皮质酮增加了近 7 倍，这种增加在短暂的再喂食期后恢复正常。从这些蜥蜴中分离出来的新鲜分散的肾上腺皮质细胞用 ACTH 孵育，并通过高度特异性放射免疫测定测量所选类固醇的产生。幼年细胞的净最大类固醇率比成年细胞高 161%。成年和幼年的孕酮率都因禁食而持续受到抑制（近 48%），但通过再喂食期恢复正常，而皮质酮和醛固酮率则出现不同的影响。禁食抑制了成年细胞的皮质酮率 43%，但不影响幼年细胞的皮质酮率。相反，禁食对成年细胞的醛固酮率没有显著影响，但却抑制了幼年细胞的醛固酮率 52%。短暂的再喂食期使成年和幼年细胞的大多数速率恢复正常，并使成年细胞的醛固酮率进一步增加 54%。喂养方案对 ACTH 敏感性的影响因生命阶段和类固醇而异。成年细胞对 ACTH 的总体敏感性接近幼年细胞的三倍。总的来说，这里呈现的数据和以前的工作数据表明，食物限制/剥夺在蜥蜴物种中导致肾上腺皮质组织的功能重塑。此外，生命阶段为这种重塑增加了更多的复杂性。
