Richard

M.

Freeman,3

M.D.,

and

ABSTRACT lism

The

in the rat

intravenous hours 16.78

± 1.90

of intravenous

with

infusion These

values diluent

zinc

were

Plasma

to

and

of this cation given histidine

observed

orally

or kidney

of 110

zinc

In conclusion, or parenterally.

of histidine

9 jcg/100

±

content.

histidine Evidence

for

Am.

administration.

plasma (1-8). -

globulin

and

this may

be the transport

(4,

one

6). Henkin et al. (9) orally to humans and

increase

as a significant

rum zinc. There is, therefore, in vivo and in vitro studies

in urinary

decrease

evidence that amino

in se-

from acid

binding of zinc might be. important in the transport of this divalent cation. This prompted us to study the influence of histidine administration on zinc metabolism in rats.

Materials Acute

infusion

and methods study

Twenty-two male Sprague-Dawley rats weighing between 160 to 260 g which had been previously maintained in a group cage with regular rat chow (containing 150 ppm zinc) and deionized water ad libitum were paired off for simultaneous infusions. The rats were anesthetized with sodium pentobarbital (0.2 ml intra-

peritoneally The American

7.58

±

the prehistidine

at the end

of solution Journal

containing of

Clinical

50 mg/mI), Nutrition

ml,

increased

that protein-bound in two forms one

a 6- to 20-fold

as well

than zinc

diluent

and a 30: APRIL

zinc

lesions

urinary

Nutr.

0.97,

20.21

however,

the

hour

During ±

value

the

2.07, and and

higher

was 76 ± 5 tag/1 00 studies:

histidine

(500

in histidine treated rats was no difference in the deficiency

in the

30: 523-527,

metabo-

by constant

During pg/hr.

infusion

of zinc

excretion

deficiency,

J. Clin.

alone. (SE) infusion

of the

No histological

testicular,

esophagus.

levels

loosely bound to albumin. It has been more recently suggested that a small percentage of zinc is bound to amino acids (in particular histidine

zinc

averaged

on zinc was given

± 0.37

plasma,

Vikbladh (1) suggested zinc is in the plasma

cysteine)

0.435

Chronic

to control

The status of zinc in circulating been of interest for several years

form have

receiving

mg/hr)

excretion this there

tered

and

animals

excretion

administration (250

averaged

all higher

alone.

histidine

histidine

P

Influence of histidine administration on zinc metabolism in the rat.

Richard M. Freeman,3 M.D., and ABSTRACT lism The in the rat intravenous hours 16.78 ± 1.90 of intravenous with infusion These values dilu...
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