Changes 。f Pーasma Ket。ne B。dy LeVGーS and Lip。ー猶iC Reacti

人間科学研究 Vo1．
18，SupP1ement
（2005）
修士論文要旨
Changes ofP1asma Ketone Body Leve1s and Lipo1皿ic React1ons
During Fasting in In危nt，Adu1t and Aged Rats
Yuriko HIGASHINO
Director：Kazuhiko IMAIZUMI
Introduction
technique．After the fasting，the weights of perirena1and
AI11iving mammaIs require a constant source of energy
periepididymaI white adipose tissues were weighed．
to maintain their1ife activities and optimaI growth．The
sum of the intake of several nutrients such as carbohy−
Resu1ts and Discussion
drate，fat and protein comprises the totaI food energy
1．PIasma glucose，insulin and trigIyceride concentra−
ingested．It is important for mammals to provide energy
tions in three life stages of rats decreased significantIy
continuously because ofthe intermittent intake offood．In
during fasting．
the reguIation of food intake，metaboIic pattems change
21Plasma free fatty acid，tota1ketone body andβ一
drastica11y．Hepatic g1ycogenolysis，g1uconeogenesis，and
hydroxybutyrate，acetoacetate concentratioPs in three1ife
particular1y lipolysis in adipose tissues are known to p1ay
stages of rats increased during fasting．The increased pat−
important roles in supPlying energy sources during
terns of these p1asma leveIs were a1most similar in all1ife
fasting．On the other hand，dramatic changes of metab−
stages of rats．However，the magnitude of the increased
o1ism occur in each deve1opmentaI stage，particuIarly in
leve1s was age−dependent，higher in the order of aged，
infant period．However，the age−related effects of fasting
adult and infant rats．
on lipid metabolism，which p1ays a cruciaI role in supp1y−
3．The times required to reach maxima1concentrations of
ing most of the energy，are still unknown．In the present
pIasma ketone body1evels and free fatty acid were earlier
study，therefore，plasma ketone body（totaI ketone body，b−
in the order of infant，adult and aged rats，suggesting that
hydroxybutyrate and acetoacetate），free fatty’acid，tri−
lipoIysis in infant rats was prompt王y induced．
glyceride leve1s，and white adipose tissue Ievels in three
4．The weights of two adipose tissues in three life stages
life stages（infant，adu1t and aged〕of rats were investi−
of rats decreased significantly．Mean decreased rates of
gated to eIucidate systematicalIy their effects．
two adipose tissues weights were higher in the order of
infant，adult and aged rats，suggesting that fasting induces
age−dependent decreasing actions of adipose tissues．
Methods and Materia1s
l）Bxperimenta1designs and animals：Infant（3weeks），
Further，total quantities｛＝Peak integra1s〕of free fatty acid
adult（8weeks）and aged（32weeks）ma1e Sprague Dawley
and ketone body levels mobiIized into plasma during
rats were used．The animals（n＝S−9／9roup〕were divided
fasting were proportiona1to the decreased weights of
into the control（CON〕groups and the fasting（PAS）
adipose tissues．These results indicate that free fatty acid
groups．Fasting of infant，adu1t and aged rats were
and ketone body derived into pIasma during fasting are
maintained for2，5and13consecutive days，respective1y．
completely originated from1ipolysis in adipose tissue．
Cube diets were given to the CON group rats，and once−
boiled tap water was given to both groups∂ゴ〃伽”〃。
Conc1usion
2）Methods：BIood samples in three life stages of rats
The present study showed that fasting in rats increased
were col1ected from taiI vein and pIasma was prepared by
plasma ketone body leve1s．The pattems of mobi1ization
the centrifugation（12，OOO”㎜for5”加）．Plasma total
of ketone body into plasma during fasting were clear1y
ketonebody，β一hydroxybutyrate，freefattyacid，9Iucose
age−dependent．These results suggest that fasting−induced
and trigIyceride concentrations were assayed by the rou−
Iipo1ytic actions are age−dependent and are c1ose1y
tine spectrophotometric methods．P1asma insu1in assays
re1ated to the differences in metabo1ic tumover rate and
were carried out by the enzyme−1inked−soIvent assay
the energy storage in the body in each1ife stage．
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