HORMONAL-REGULATION OF AMINO-ACID-TRANSPORT AND CAMP PRODUCTION IN MONOLAYER-CULTURES OF RAT HEPATOCYTES
HORMONAL-REGULATION OF AMINO-ACID-TRANSPORT AND CAMP PRODUCTION IN MONOLAYER-CULTURES OF RAT HEPATOCYTES
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DOI：
10.1002/jcp.1041030120
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发表时间：
1980-01-01
影响因子：
5.6
通讯作者：
POTTER, VR
中科院分区：
文献类型：
--
作者：
KELLEY, DS;SHULL, JD;POTTER, VR
本文研究了胰岛素[I]、胰高血糖素[G]、地塞米松（DEX）及G与I或DEX合用对大鼠肝细胞摄取2-氨基[1- 14 C]异丁酸（AIB）和N-甲基-2-氨基[1- 14 C]异丁酸（NMeAIB）的影响。I和G刺激了氨基酸的摄取，DEX抑制了氨基酸的摄取，表明所有3种激素都调节A系统（允许NMe AIB转运的Na依赖性系统）在这些培养物中进行氨基酸转运。研究在过量AIB存在下或在Na不存在下氨基环戊烷-1-羧酸，1- [羧基-14 C]的运输的实验表明，I对L系统（偏好亮氨酸的Na非依赖性系统）的活性没有影响。在过量NMe AIB存在下对AIB摄取的实验表明，I对ASC系统（不转运NMe AIB的Na依赖性系统）的转运活性没有影响。I浓度范围为0.1 nM-100 nM，不拮抗最佳或次佳浓度的G对AIB或NMe AIB摄取的刺激作用。同样，G没有拮抗的刺激作用的最佳或次最佳浓度的I对这两种氨基酸的摄取。I和G的组合效应对AIB和NMe AIB的速率以及累积摄取都是加和的。DEX单独抑制AIB和NMe AIB的转运。25%，而G引起2-3倍的增加;当与仅含有DEX的培养物相比时，向含有DEX的培养物中添加G引起AIB和NMe AIB两者的摄取增加7-8倍。还研究了I对c[环]AMP水平的影响。I对用最佳或次佳G浓度处理或未处理的培养物中的cAMP水平没有影响。
The effects of insulin [I], glucagon [G] or dexamethasone (DEX) and of G with I or DEX were examined on the uptake of 2-amino [1-14C]isobutyric acid (AIB) and N-Methyl-2-amino [1-14C]isobutyric acid (NMeAIB) in monolayer cultures of rat hepatocytes. I and G stimulated the uptake of both the amino acids and DEX inhibited it, showing that all 3 of these hormones regulate the A system (the Na-dependent system that permits the transport of NMe AIB) for amino acid transport in these cultures. Experiments investigating the transport of aminocyclopentane-1-carboxylic acid, 1- [carboxyl-14C] in the presence of excess AIB or in the absence of Na showed that I had no effect on the activity of the L system (the Na-independent system that prefers leucine). Experiments on the uptake of AIB in the presence of excess NMe AIB showed I had no effect on the transport activity of the ASC system (the Na-dependent system that does not transport NMe AIB). I concentrations ranging from 0.1 nM-100 nM did not antagonize the stimulatory effect of optimum or suboptimum concentrations of G on the uptake of either AIB or NMe AIB. Similarly, G did not antagonize the stimulatory effect of optimum or suboptimum concentrations of I on the uptake of both the amino acids. The combined effect of I and G was additive on the rate as well as the cumulative uptake of both AIB and NMe AIB. DEX alone inhibited the transport of both AIB and NMe AIB by .apprx. 25%, while G caused a 2-3-fold increase; G addition to cultures containing DEX caused a 7-8-fold increase in the uptake of both AIB and NMe AIB when compared to cultures containing DEX alone. The effect of I on the c[cyclic]AMP levels was also investigated. I had no effect on the cAMP levels in cultures treated or untreated with optimum or suboptimum G concentrations.