On the nature of adrenocorticoid-induced increase in tyrosine-α-ketoglutarate transaminase activity of rat liver

Vol. 2, No. 5

BIOCHEMICAL

ON

AND

THE NATURE IN

BIOPHYSICAL

OF

TYROSINE-a-KETOGLUTARATE

A rapid liver

after

found

that

the

and specific

the

rendered

thus seem

that

be influenced nature

has been

investigated

immunized

rabbits. and

‘operated

that

1

extensions

by Union

but effect

sharply

level

Kretchmer,

1959).

fashion

by various

in activity

amino

in “induced”

the aid of a highly

specific

enzyme

was purified

SOO-

of methods

described

previously

Carbide

Corporation

for

333

the

obtained

per

se is

as tyrosine

rats

is actually

nor

with

of substrate

adult

(Kenney,

a hormonal

1960). induction

acids. adult

rats

as well

antitransaminase

to 600-fold

U.

for

is as effective

in adrenalectomized

This

but supple-

that

role

In

and

development,

methionine

activity

Kenney,

than

or

birth.

substitutes

A specific

that

is given.

is involved. after

neither

of activity

also

not by phenylalanine

(Serini,

tyrosine

of rat

They

hydrocortisone

immediately

steroids

activity

(1957).

of tyrosine

transaminase

in transaminose

change

The

by tyrosine,

newborns,

to hydrocortisone

with

unless

on adrenal

in o higher

Knox

to tyrosine

increases

by the observation

in some

by Lin and

in restoring

and

transaminase

substrate-inducing

dependent

alteration

of the

observed

to respond

transaminase

(Kenney

the response

The

a specific

results

improbable

It would can

fail

first

of hydrocortisone

alone

in increasing

Kenney

is augmented

is also

methionine

hydrocortisone

was

In adrenalectomized

effect

with

further

of this

1959).

mentation

cations

that

increase

augments

T.

in tyrosine-a-ketoglutarate

administration

the activity

Kretchmer,

LIVER

increase

rats

suggesting

developmental

RAT

Biology Dlvision Ridge National Laboratory Oak Ridge, Tennessee

administration

to steroid

rat,

OF

Oak

adrenalectomized

glutamate,

INCREASE

14, 1960

substrate

Response

1960

TRANSAMINASE

Francis

April

May

COMMUNICATIONS

ADRENOCORTICOID-INDUCED

ACTIVITY

Received

RESEARCH

from

as in newborns from

rat

(Kenney,

1959)

S. Atomic

Energy

the

livers

sera

of

by modifi-

and was

Commission.

administered

Vol. 2, No. 5

BIOCHEMICAL

to rabbits

in Freund’s

enzyme,

and

enzyme was

carried of the

2 l/2

hr apart.

of isotope.

given

taken

the mixtures

were

radioactivity -M

activity

are

genitally not

for

were

killed

These

were

presented

reactive

1.

induction

protein, affected

and by

activity

precipitate

Ag-Ab

radioactivity

Soluble

protein

cleared

from

activity

overnight

at 3”.

determined

the

of the

and

a corresponding

Table

1

Induction

similar

(units)

(cpm) (cpm)

acid

experiments,

for

were

determined, and

content

after

and

washing removal

of

materials.

The

in transaminase increase

into

this

in antiprotein

transaminase

Liver

Control

Induced

7.7

248.8

117

128

49

55

157

209

* All data are expressed in terms of a constant amount of the soluble fraction and are the averages of values obtained in determinations on 4 animals in each group. Protein content and radioactivity of antigen-antibody (Ag-Ab) precipitates were not corrected for antibody. 334

30 min;

denaturation.

of Tyrosine-a-Ketoglutarate in Rat

first and

extensive

increase

amino

the

Protein

fraction

that

of isotopic

in

in excess,

after

It is apparent

with

with

protein

was added

marked

and,

thermal

and

of the soluble

doses,

at 37’

Antibody

were

In this

leucine

by heating

the enzyme

then

in two

of the experiment,

ethanol-ether-soluble

(pg)

radioactivity

further

the start

and

incorporation

the experiment.

mg/kg)

acid-soluble,

Measurement* Transaminase

5 hr after

associated

phenomenon

before

(600

the

the purified

induction

isotopic

tyrosine

tests.

Transaminase

Ag-Ab

with

and

protein

and

intraperitoneally

tmnsaminase

total

is not

Assay

of the

May 1960

inactivated

antibody

13 days

treated

at 37“,

and

between

-leucine

to protect

induction.

lmmunochemical

precipitated

Analysis

precipitate

of the

in Table from

14

precipitin

antigen-antibody

trichloroacetic

gel.

(30 mg/kg)

was added

that

reaction

similarly

for 30 min

hot

appreciably

were

quantitative

and

the

of C

precipitate,

incubated

obtained

adrenalectomized

8~

prepared.

NaCI,

resulting

been

received animals

thus

in agar

had

The animals

of the

acid-soluble, results

that

of the resulting

aliquots

0.15

diffusion

(5 X 10m3 5)

removal

when

hydrocortisone

fractions

a-ketoglutarate

with

is found

group

Induced

injection

and

rats

control

were

After

band

using

addition,

soluble

Antisera

by double

out

Those

liver

adiuvant.

a single

is studied

AND BIOPHYSICAL RESEARCH COMMUNICATIONS

is

Vol. 2, No. 5

BIOCHEMICAL

activity

in the

livers

typical

of intact

associated

natural

appreciable

RESEARCH

adrenalectomized

presumably

the

with

BIOPHYSICAL

of noninduced

rats,

Similarly,

AND

reflecting

controls

the

effect

increase

in transaminase

increase

in antigen

lmmunochemical

Assay

after

birth

2

of the

Developmental

(Table

Increase

activity

Ag-Ab

protein h)

144.0

127

of six litter mates killed at the times indicated and procedures as described for Table 1.

synthesis

clearly

incompatible

of enzyme

protein

of an antigenically

release

of an inhibitor.

in liver

preparations

from

adrenolectomized

rats.

diffusion from

that

Mixing

noninduced

this

animals

In support

of the

gel

of crude that

that

precursor

from

being

protein,

or the

or

by the technique

a strong

after

band

induction.

Dr.

G.

David

to acknowledge

the valuable

investigated.

advice

and suggestions

observations

(1959)

of

Novelli. References

Kenney,

F.

T.,

and

Kenney,

F.

T.,

J.

Kenney,

F. T.,

Lin, Serini,

E. C. F.,

C.,

N.

Kretchmer,

Biol.

Chem.

unpublished and

F. T.

W. Kenney,

unpublished -234:

2707

observations E. Knox, and

(1959) (1960)

Biochim. N.

et Biophys.

Kretchmer, 335

J.

Biol.

Acto Chem.

-26:

85 (1957) 234: -

609

present The possi-

Acknowledgment It is a pleasure

the

of enzyme

intact

analysis reveals

either

inhibition

noninduced

or absent

is now

promote

any

other

involving

precursor

hypothesis,

preparations

protein

steroids

to demonstrate

is diminished

a precursor

adrenal

by extracts

pooled;

of induction

inactive

fail

liver

were

a mechanism

enzymically

experiments

animals

represents

but

induced

in ogar

with

and suggest

similar

is not

in

12.0

are

birth

Transaminase*

120

results

that

2).

5.5

activation

bility

after

0.5

These

in those

occurs

liver

than

1960

deprivation.

(units)

* The livers conditions

of double

lower

adrenal

that

of the

Table

Transaminase

0-d

--de novo

of prolonged

content

May

was much

activity

Tyrosine-a-Ketoglutarate

Time

COMMUNICATIONS

(1959)