vitamin C free diet. Vitamin C content of the blood was studied at regular intervals. The volunteers were also clinically examined regularly and any symptoms of vitamin C deficiency noted carefully. A graph showing mean average figures of the changes in blood vitamin C level of ten volunteers kept on vitamin C deficient diet for two months.

Blood Vitamin C level in m|m. perlOO

cc.

Scale:Scale from 0-0-5 m?ms. (1 -0?mfJms.) mgms. small sq.= -0?mgms.) from 0-5-2-0 0-5-2 0msfms.(Ismail m^ms.(Hmall sq.^ sq.-11 m|ms.) m?ms.)

BIOSYNTHESIS OF ASCORBIC ACID IN HUMAN BEINGS By R. B. ARORA,

Professor

m.d., b.s.

(Luck.)

Head of Department of Physiology, Lady Hardinge Medical College, New Delhi Introduction.?It is generally recognized that human beings, monkeys and guinea-pigs do not synthesize vitamin C in their body. The difference in the time of onset of the symptoms ?f vitamin C deficiency were attributed to differences in age, sex and locality. The great extent to which pregnant women could tolerate vitamin C deficiency could not be explained. It has, however, been suggested that possibly the fcetus synthesizes vitamin C and that this is the cause of higher tolerance levels in the case of Pregnant women. The fact that nursing mothers secrete more vitamin G in their milk than they consume has been assumed to be due to biosynthesis of vitamin C by them. What is the actual state of affairs in normal non-pregnant women and in men does not appear to have been studied. The possibility of biosynthesis of vitamin C in them has been examined in the present series of investigations.

0

J 1

I 5

l 8

I 15

I

l

20

I?i J4

25 30

_t?I?l?I?i?l?I?i?i 36 38 40

44

46

48

50 52

54

Number of s on Vitamin C deficient Diet and on-which theblood C deficient Diet and on- which the bloodof ofthe Number ofDay the Day s on Vitamin Volunteers tor VitaminCCAnalysis wasdrawn. drawn. Volunteers forVitamin Analysiswas

and

Experimental

technique and material for normal healthy girl students and 4 healthy males between the ages of 16 and 25 were selected. The level of vitamin C in blood was estimated in every case before the experiment was started. The cases included men and non-pregnant women, 6 of whom were vegetarians and 4 taking a mixed diet. The method used Was the volumetric method of Farmer and Abt Jn which the plasma proteins are precipitated with metaphosphoric acid and the ascorbic acid solution titrated with standardized 2 : 6 indophenol-sodium solution. The above volunteers were then kept on a regulated

study.?Six

jn dichlorophenol

Discussion

of

results

As will be observed from the graph, there is a gradual decline in the vitamin C content of the blood on the vitamin C free diet given to the volunteers. This decline reaches the lowest level on an average in 36 days. Although this period differs from individual to individual, a time does come when every individual reaches a minimal level. It is after this minimal level has been reached that the quantity of vitamin C in the blood begins to rise and this continues for about 18 days. Here also there is an individual variation and every individual has his or her own time limit up to which a gradual rise continues. It is generally during this period that symptoms of vitamin C deficiency manifest themselves and further experimentation had to be discontinued on account of the reluctance of the volunteers to undergo further investigations. It therefore appears that when a minimal level of vitamin C in blood has been reached human body tries to overcome this deficiency by synthesizing vitamin C itself or there might be a rush of vitamin C from the tissues in the blood to maintain a minimal level. In any case the rise in the level of blood vitamin C is not sufficient to withstand deficiency symptoms and the small response which may be due either to synthesis or exchange is insignificant.

Summary content of

1. Vitamin C human volunteers kept diet was examined.

on

the_

blood of

10

vitamin C deficient

288

THE INDIAN MEDICAL

2. It has been found that there is a gradual decline for a definite period up to 36 days the minimum vitamin C level in the blood in mg. per 100 cc. blood reaching 0.02 mg., after which there is an average rise to a maximum of 0.23 mg. per cent in blood. The writer is indebted to Professor S. N. Mathur, ph.D. (Lond.), Professor and Head of the Department of Physiology, Lucknow University, for suggesting this, still unexplored, problem and for his continued help throughout the course of this work. BIBLIOGRAPHY

Bicknell, F., and Prescott, F. (1946). Hjarre, A., and LilleENGEN, K. (1936). McCarrison, R. (1930). Rosenberg, H. R. (1945). H. M., Burke, B. S., and Draper, R. (1938).

Teel,

Vitamins

in MedicineWilliam Heinemann Ltd., London. Virchow's Arch. Path. Anat.,

297,

565.

Studies in Deficiency Diseases. Henry Frowde and Hodder and Stoughton, London.

Chemistry and Physiology of

Vitamins. Interscience Publishers Inc., New York. Amer. J. Dis. Child, 66, 1004.

GAZETTE

[July,

1949

Biosynthesis of Ascorbic Acid in Human Beings.

Biosynthesis of Ascorbic Acid in Human Beings. - PDF Download Free
3MB Sizes 0 Downloads 7 Views