S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Medicine (의학과) The Seoul Journal of Medicine The Seoul Journal of Medicine Vol. 09 No.1 (1968)
Walker 256 종양에 있어서 C14-포도당 및 C14-젖산의 산화대사
Oxidative Metabolism of C14-Glucose and C14-Lactate in the Walker 256 Tumor
- 구철회; 이상돈
- Issue Date
- 서울대학교 의과대학
- Seoul J Med, Vol.9 No.1, pp. 1-9
- Tissue homogenates of Walker 256 tumor were incubated
separately in medium containing 04-1-glucose, 0 46-
glucose, OL1-lactate, OL2-lactate, and C~3-lactate
in order to observe' the oxidative metabolism of each
carbon of substrates which labelled by 0 4• Glucose
and lactate media, in which tissue homogenates were
incubated, were kept at a concentration of 200mg% and
50mg%, respectively. At the end. of 3 hours incubation,
respiratory CO2 samples trapped by alkaline which was
placed in the center well of the incubation flask were
analyzed for total CO2 production rates and their radioactivities.
The tissue homogenate samples after incubation
were analyzed for their concentrations of glucose, lactateand
pyruvate. Calculations were made on the glucose
consumption rate and accumulation rates of lactate and
pyruvate. The following results were obtained.
1. In the tissue homogenate, which was incubated with
OLglucose as a substrate, total CO2 [production rate
averaged 10. 0±2.1 J.lM/hr/gm and CO2 productions from
C-1 and C-6 carbon of glucose were means of 23.1
and 2. 6% respectively.
2. Glucose uptake rate in the OLglucose incubation
experiment was mean of 14. 3±2. 9 J.l M/hr/grn. The
fraction of glucose oxidized into C~ to total glucose
uptaked (RGD C02) was only 0.7%. On the other hand,
lactate and pyruvate accumulation rates averaged 14. 1
±3.4 and O.33±0. 6 pM/hr/ gm, respectively, Assuming:
that these 3 carbon compounds appeared in the medium
were derived from glucose, the relative glucose
disappearance rete into lactate(RGDt.) was 48. 9% and
RGDi> was 1. 29;}. Therefore, abouth 50; 8% of total
glucose uptaken were accounted for by conversion into.
respiratory CO2• lactate and pyruvate.
3. The oxidative pathway of glucose in the tumor
tissue was analyzed from the values of relative specific
activities which were obtained in the OL1 and 0 4- & -glucose incubation experiments. It was found that
11. 3% of CO2 deriven from glucos were via the principal
EMP-TCA cycle and the remainder were via the
alternate pathway such as HMP.
4. In the Of-lactate incubation experiments, total
CO2 production rate was mean of 10.2 ,uM/hr/gm which
showed same order in value obtained in the C14-glucose
incubation. Lactate was accumlated to about O. 244 mg/hr/
gm from endogenous source in every run of experiments.
The pyruvate accumulation rate was mean of O.045 mg/
Respiratory C14 O2 yield from C-1 carbon of lactate
was 13.8-2.3% of total CO2 production rate and this
proportion was larger than those from C-20r C-3 carbon of
lactate whose values showed 3.78-1.1 and 7.97-2.1,
respectively. It shows that carboxyl carbon of lactate
contributes a larger proportion in producing respiratory
CO2 than 2 and 3 carbons of lactate.
From the data described above, it was assumed that
anaerobic glycolysis proceeds normally, resulting in the
accumlation of lactate in the Walker 256 tumor but
farther oxidation via the TCA cycle was remarkably
inhibited and almost all of oxidative energy from glucose
was released by alternate pathway such as HMP.