Tovar Armando R, Ascencio Claudia, Torres Nimbe
Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City DF 14000, México.
Am J Physiol Endocrinol Metab. 2002 Nov;283(5):E1016-22. doi: 10.1152/ajpendo.00398.2001.
Glucagon has been postulated as an important physiological regulator of histidase (Hal) gene expression; however, it has not been demonstrated whether serum glucagon concentration is associated with the type and amount of protein ingested. The purpose of the present work was to study the association between hepatic Hal activity and mRNA concentration in rats fed 18 or 50% casein, isolated soy protein, or zein diets in a restricted schedule of 6 h for 10 days, and plasma glucagon and insulin concentrations. On day 10, five rats of each group were killed at 0900 (fasting), and then five rats were killed after being given the experimental diet for 1 h (1000). Rats fed 50% casein or soy diets showed higher Hal activity than the other groups studied. Rats fed 50% zein diets had higher Hal activity than rats fed 18% casein, soy, or zein diets, but lower activity than rats fed 50% casein or soy diets. Hal mRNA concentration followed a similar pattern. Hal activity showed a significant association with serum concentrations of glucagon. Serum glucagon concentration was significantly correlated with protein intake. Thus the type and amount of protein consumed affect Hal activity and expression through changes in serum glucagon concentrations.
胰高血糖素被认为是组氨酸酶（Hal）基因表达的重要生理调节因子；然而，血清胰高血糖素浓度是否与摄入蛋白质的类型和数量相关尚未得到证实。本研究的目的是探讨在为期10天、每天6小时限时进食的条件下，给大鼠喂食18%或50%酪蛋白、分离大豆蛋白或玉米醇溶蛋白日粮后，肝脏Hal活性和mRNA浓度与血浆胰高血糖素和胰岛素浓度之间的关系。在第10天，每组五只大鼠于09:00（空腹）处死，然后另外五只大鼠在给予实验日粮1小时后（10:00）处死。喂食50%酪蛋白或大豆日粮的大鼠的Hal活性高于所研究的其他组。喂食50%玉米醇溶蛋白日粮的大鼠的Hal活性高于喂食18%酪蛋白、大豆或玉米醇溶蛋白日粮的大鼠，但低于喂食50%酪蛋白或大豆日粮的大鼠。Hal mRNA浓度呈现类似的模式。Hal活性与血清胰高血糖素浓度显著相关。血清胰高血糖素浓度与蛋白质摄入量显著相关。因此，摄入蛋白质的类型和数量通过血清胰高血糖素浓度的变化影响Hal活性和表达。
