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The Effects of Tryptophan and Leucine On Moving Ability of The Organism and Their Interaction
LI Li LIU Zuoqiang QIAO Xiaoyu LAN Kai LI Zhaopei Class 1， Grade 2000， Department of Clinic Medicine Sun Yat-sen University，Guangzhou 510089，P．R．China Tutor： WANG Tinghuai Department of Physiology Sun Yat-sen University， Guangzhou 510089， P．R．CHINA ［Abstract］ Objective To discuss the effects on the moving ability of the organism and the interaction of Tryptophan and Leucine． Methods Perfuse the little mice with the solution of Trp and Leu． And then measure how long the mice will swim． Results The control group and the experimental group have significant difference. Conclusions Trp has obvious effect of fatiguing the mice while Leu has the contrary effect． But when mixed， Trp and Leu hardly have any effect on the living mice． ［Key Words］Tryptophan (Trp) Leucine (Leu) Moving ability Constant swimming time 1 Preface
Amino acid is a synthetical material of protein and can produce energy from oxidation in the body． Some of them are regulatable factors of the body and play an important role in movement． A number of researches [1] have been conducted these years ． Muscle is the main metabolism site of BCAA， so it may be true that supply the amino acid can improve the moving ability and stamina of the body． And it is said that the concentration of BCAA in the blood plasma of the rat after exercises is reduced distinctly after the stamina training． Long-time exercise can lead to the change of the composition of free amino acid that causes the fatigue of the motor center． Supplying BCAA can reduce the fatigue of the center． But there are also other reports exercise the concentration of [2] BCAA in the muscle does not change and there are not any results showing BCAA can improve the moving ability ． Fatigue is the phenomenon that the work efficiency is distinctly reduced temporarily caused by long-time heavy and tense physical or mental work． So far as is known， the causes of fatigue include： (1) exhaustion + of creatine (2) increase of concentration of H in muscle tissue． (3) exhaustion of muscle hepatin． (4) decrease of blood sugar (5) increase of Trp-Leu ratio in the blood plasma and so on． The last two causes [3] are more essential ． This article tries to discuss the effects of Trp and Leu on the mouse’ moving ability and their interaction in view of their metabolism feature in the body． 2 Materials and Methods
2.1 Drugs or reagents Trp solution (10．0mg/ml) Leu solution (10．0mg/ml) 2.2 Animals grouping 64 white mice (male， 18-22g)， divided into 8 groups at random， 8 for each group(It is the fewest number of mice left if some of them die during the experiment) 2.3 Methods and observation points (1) Grouping： perfuse each group one time per day， 7 days totally． First group： control group using physiological saline (0．5ml) Second group： Trp low dose group (0．25mg/g) Third group： Trp moderate dose group (0．50mg/g) Fourth group： Trp high dose group (1．00mg/g) Fifth group： Leu low dose group (0．25mg/g) Sixth group： Leu moderate group (0．50mg/g) Seventh group： Leu high dose group (1．00mg/g) Eight group： mixed group (1．00mg/g， 0．5mg/g each solute) (2) Observation points： observe how long the mouse can swim in the trough． Take that the mouse’s head is under the water for at least 7s as the end of the swimming． The time how long it swims in the water is the index of fatigue．
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2.4 Data processing (ANOVA) 3 Results Groups Table 1 Statistical results of each group Number Swimming time (s) 8 8 8 8 8 8 8 8 Comparison of each group 328．8±6．618 311．0±17．64 281．7±8．269 186．94±13．67 414．3±11．43 514．0±22．84 619．97±24．88 328．17±28．75
1)control group 2)Trp low dose group 3)Trp moderate dose group 4)Trp high dose group 5)Leu low dos group 6)Leu moderate dose group 7)Leu high dose group 8)mixed group Chart1
Data analysis：(main calculating process omitted) ν1=8-1=7， ν2=64-8=56， MSB=SSB/ν1， MSW=SSW/ν2， MSB/MSW=15．7319， for F0．1=1．82 F0．05=2．17 therefore F>F0．05 therefore P<0．05 It can be concluded that the eight groups of data have distinct differences． 4 Discussion
From above result we can see that as the concentration of the perfused Trp solution increases， the swimming time of the mouse decreases distinctly and as the concentration of Leu solution increases the swimming time of the mouse increases distinctly． As you know， Trp is the necessary aminophenol of human body． It can be metabolized into nicotinic acid and other substance in the liver． But it is mainly decarboxylated--hydroxylated into 5-HT． 5-HT has many
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physiological regulation effects， especially to the central nervous system． As a kind of neurotransmitter， 5-HT can control the feeling of fatigue and sleep． It is the free Trp but not 5-HT that passes through the blood-brain barrier． In the normal human body， there are certain amounts of necessary aminophenol such as free Trp， Leu etc． The free Trp enters the brain tissue be synthesized to 5-HT with the help of hydroxylase． Increase of the concentration of 5-HT in the brain leads to physical and mental fatigue． Trp is the only one of amino acid that can bind to albumin． In the blood plasma， they can got together or be separate． Generally， the two forms are at balance． But under certain condition， increase of fat mobilization， for example， fatty acid are increasingly freed into the blood， its concentration rises up， and because fatty acid can bind to albumin too， the high-concentration fatty acid will compete to bind to albumin with [5] Leu， which break the balance and cause the increase of free Trp in the plasma and brain ． In this experiment， we increase largely the amount of Trp taken in by the mouse (more than 10 times) to increase the concentration of Trp in the plasma． It shows that the swimming time of the loaded mouse is shortened distinctly， i．e． as the dose of drug increases from low to high， the swimming time increases from 311．0s， 281．7s to 186．9s， i．e． the more the drug dose increases， the shorter the time is， the more distinct the inhibitory effect is． The Trp-BCAA ratio is one of the important factors that affect the entry of Trp． Trp and BCAA pass through the blood-brain barrier by the same carrier， there is a compete mechanism between them． If the ratio rises， Trp will enter the brain more easily and then leads to the increase of 5-HT， which cause physical and mental fatigue． If the ratio falls， the result will be the opposite． Therefore， increase the concentration of Trp will cause fatigue while increase the concentration of BCAA will mitigate the feeling of fatigue． As is shown above， largely increased the amount of Leu taken in (more than 10 times)， the swimming times of the mice are distinctly prolonged than the control group (328．8s)． And as the drug dose increases， the swimming time increases from 414．3s， 514．0s to 619．97s． That is， the higher the dose is， the longer the time is． Finally， when we increase both of the doses of Trp and Leu， the result is not obviously different from the control group (328．17s)． 5 Conclusions
Trp may impair the moving ability of the body， making the body tend to fatigue． BCAA may improve the moving ability of the body， retarding fatigue． Using the two together hardly has any effect on the body． References(refer to Chinese version)
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