食物限制、禁食、糖尿病及甲状腺切除对大鼠垂体生长激素和促甲状腺激素基因表达的比较影响

Comparative effects of food restriction, fasting, diabetes and thyroidectomy on growth hormone and thyrotropin gene expression in the rat pituitary.

作者信息

Rodríguez M, Rodríguez F, Jolin T, Santisteban P

机构信息

Instituto de Investigaciones Biomédicas, CSIC (Consejo Superior de Investigaciones Científicas), Madrid, Spain.

出版信息

Eur J Endocrinol. 1995 Jul;133(1):110-6. doi: 10.1530/eje.0.1330110.

DOI:10.1530/eje.0.1330110

PMID:7627331

Abstract

To examine the molecular basis for the decreased pituitary growth hormone (GH) and thyrotropin (TSH) content during restricted feeding, fasting and diabetes, we measured steady-state levels of mRNA for TSH-alpha, TSH-beta and GH in the pituitary from normal rats either fed ad libitum (C), limited to 75%, 50% and 25% (FR75, FR50, FR25, respectively) of ad libitum intake, or deprived of food for 2 and 4 days (F2 and F4, respectively), and also in streptozotocin-diabetic (D) and D insulin-treated animals. The results from these experimental groups were compared with those in thyroidectomized (Tx) rats. Pituitary mRNA was quantified by Northern blot hybridization with cDNA probes specific for rat TSH-alpha, TSH-beta and GH. Although changes in the pituitary GH mRNA during restricted feeding, fasting and diabetes were similar qualitatively to those induced by hypothyroidism, GH mRNA levels in Tx rats (> 10% of C values) were less than in the other experimental groups (p < 0.001). Pituitaries from FR50, FR25 and D rats also contained less GH mRNA than F2 and F4 animals (p < 0.05). Thyroidectomy resulted in a marked increase in both TSH-beta and TSH-alpha mRNAs, the changes in TSH-beta mRNA being greater than those in TSH-alpha mRNA. In contrast, FR50, FR25, F2, F4 and D rats exhibited a decrease in pituitary TSH-beta mRNA (60%, 50%, 35%, 36% and 33%, respectively, of C values; p < 0.01-0.05) and in TSH-alpha mRNA levels (81%, 64%, 46%, 43% and 36%, respectively, of normal values; p < 0.02-0.05), TSH-beta mRNA showing the greater changes.(ABSTRACT TRUNCATED AT 250 WORDS)

摘要

为研究限食、禁食和糖尿病期间垂体生长激素（GH）和促甲状腺激素（TSH）含量降低的分子基础，我们测定了正常大鼠垂体中TSH-α、TSH-β和GH的mRNA稳态水平。这些大鼠要么自由采食（C组），要么限制采食量为自由采食量的75%、50%和25%（分别为FR75、FR50、FR25组），要么禁食2天和4天（分别为F2和F4组），同时还测定了链脲佐菌素诱导糖尿病大鼠（D组）及D组胰岛素治疗动物的上述指标。将这些实验组的结果与甲状腺切除（Tx）大鼠的结果进行比较。用针对大鼠TSH-α、TSH-β和GH的cDNA探针通过Northern印迹杂交对垂体mRNA进行定量。尽管限食、禁食和糖尿病期间垂体GH mRNA的变化在性质上与甲状腺功能减退诱导的变化相似，但Tx大鼠的GH mRNA水平（>C组值的10%）低于其他实验组（p<0.001）。FR50、FR25和D组大鼠垂体中的GH mRNA也比F2和F4组动物少（p<0.05）。甲状腺切除导致TSH-β和TSH-α mRNA均显著增加，TSH-β mRNA的变化大于TSH-α mRNA。相反，FR50、FR25、F2、F4和D组大鼠垂体TSH-β mRNA（分别为C组值的60%、50%、35%、36%和33%；p<0.01 - 0.05）和TSH-α mRNA水平（分别为正常值的81%、64%、46%、43%和36%；p<0.02 - 0.05）降低，TSH-β mRNA变化更大。（摘要截断于250字）