Agricultural Science Digest
Vol. 11, Jan. - Feb., 1969
PURDUE UNIVERSITY
DISTRIBUTION OF RADIOACTIVITY

COMPARISON OF pH

Using twelve well-trained English
Pointer dogs about 1.5 years old, veterinary
scientists took blood samples from the neck,
inguinal area and tip of the tail. With Radio-
meter equipment, the pH of capillary, arter-
ial and venous blood samples were deter-
mined twice and the average of the two read-
ings recorded:
-	capillary: 7.441 and 7.427
-	arterial: 7.438 and 7.426
-	venous: 7.398 and 7.401, respectively
for the first and second series of bleedings.

The above indicates that the pH of cap-
illary and arterial blood in the dog is nearly
the same.

The pH of the capillary and arterial
blood samples of the second series of bleed-
ings was slightly less than the corresponding
samples in the first series. This may have
been caused by a lower ventilatory rate
(due to the fact that the dogs may have been
more at ease during the second bleeding).

Purdue veterinary scientists taking part
in this study agree that the use of venous
blood is a satisfactory clinical procedure
in veterinary practice. It is easier to ob-
tain than arterial blood, and the difference
between the mean values of venous blood
was less than the variation between the
means of the arterial and capillary samples.

Finally, the mean values found for the
venous blood in this study are identical with
the 7.4 universally accepted value of pH of
the blood.

Journal paper 3653, J. M. Carter and
Duane Brobst, Department of Veterinary
Science

The distribution and binding of radio-
active hydrocortisone to proteins in different
tissues of pigs were studied by Purdue re-
searchers. Pigs were used since larger
tissue samples were available and are com-
parable to man in many physiological as-
pects.

In order to detect action sites of the
hormone, the studies were made with re-
spect to: (1) concentration of radioactivity
in different tissues of the pig 45 minutes
after an IV injection of ^3H-hydrocortisone;
and (2) degree of binding of the radioactive
steroid to protein molecules in the different
tissues.

Results indicated that only the liver was
capable of concentrating radioactivity from
the blood. The brain, thymus and heart
showed less radioactivity than that in the
plasma, while activity in the testes, pitui-
tary, skeletal muscle and spleen was iden-
tical with the plasma.

Binding of radioactivity to protein mole-
cules in the liver, spleen and thymus was
found by means of molecular-sieve chroma-
tography on Sephadex G-100.

Although there is no evidence to verify
it, it seems possible that there may exist
a relationship between the intracellular
binding of the radioactivity to large mole-
cules and physiological action of steroids.

Journal paper 3630, G. D. Bottoms,
R. Stith and R. Burger, Dept, pf Physiology
and Pharmacology.

EFFECT OF ASCORBIC ACID

Purdue veterinary scientists
tested the effects of ascorbic
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