1. PENTOSE PHOSPHATE CYCLE
43
The state of the endocrine and the administration of certain hormones
also regulate the activities of the liver dehydrogenases. Thus, from Table
VI, one can see that removal of the adrenals or the pituitary glands does
not markedly affect the levels of G-6-P DH and 6-PG DH. Subsequent
administration of hormones also has no striking effect. (The enhancement of activity of 6-PG DH to 159% of normal in the adrenalectomized
TABLE VI
EFFECT OF THE ENDOCRINE STATE AND DIET SCHEDULE ON THE ACTIVITIES
OF G-6-P DH AND 6-PG DH IN THE RAT LIVER
% of control activity
Expt.
no.
Endocrine state
Diet regime G-6-P DH 6-PG DH Reference
1
Normal (C)«
Fed
100
100
(287)
Adrenalectomized (A)
Fed
82
77
(287)
2
A + 0.9% NaCl (C)
Fed
100
100
(287)
A + cortisone
Fed
89
127
(287)
A(C)
Fed
100
100
(808)
3
A + cortisone
Fed
133
159
(808)
A + cortisone + ethionine Fed
126
86
(808)
Normal (C)
Fed
100
100
(296)
4
Hypophysectomized (H)
Fasted 1 day
23
17
(296)
Η
Fasted 1 day,
28
28
(296)
refed 1 day
5
Η + 0.9% NaCl (C)
Fed
100
100
(287)
Η + cortisone
Fed
101
152
(287)
a (C) = control for the particular series of experiments.
rat treated with cortisone was not considered as significant whereas the
increase of this same enzymatic activity in the case of the hypophysectomized rat plus cortisone was considered to be significant by these same
workers.) In contrast to these results, Willmer (306) found that adrenalectomy of the rat decreases the activity of G-6-P DH, but does not alter
that of 6-PG DH. In vivo administration of either cortisone or corticosterone to these rats restores the activity of G-6-P DH to normal.
On fasting the hypophysectomized animal, however, a complicated
picture arises. First, such rats starved for 1 day decrease markedly both
hepatic dehydrogenase activities. On refeeding them, no significant rise
in either of the activities was observed. This is in sharp contrast to a
1-day fast of nonhypophysectomized rats which produces an increased
level of G-6-P DH and which at the end of 2 days of fasting reduced
43
The state of the endocrine and the administration of certain hormones
also regulate the activities of the liver dehydrogenases. Thus, from Table
VI, one can see that removal of the adrenals or the pituitary glands does
not markedly affect the levels of G-6-P DH and 6-PG DH. Subsequent
administration of hormones also has no striking effect. (The enhancement of activity of 6-PG DH to 159% of normal in the adrenalectomized
TABLE VI
EFFECT OF THE ENDOCRINE STATE AND DIET SCHEDULE ON THE ACTIVITIES
OF G-6-P DH AND 6-PG DH IN THE RAT LIVER
% of control activity
Expt.
no.
Endocrine state
Diet regime G-6-P DH 6-PG DH Reference
1
Normal (C)«
Fed
100
100
(287)
Adrenalectomized (A)
Fed
82
77
(287)
2
A + 0.9% NaCl (C)
Fed
100
100
(287)
A + cortisone
Fed
89
127
(287)
A(C)
Fed
100
100
(808)
3
A + cortisone
Fed
133
159
(808)
A + cortisone + ethionine Fed
126
86
(808)
Normal (C)
Fed
100
100
(296)
4
Hypophysectomized (H)
Fasted 1 day
23
17
(296)
Η
Fasted 1 day,
28
28
(296)
refed 1 day
5
Η + 0.9% NaCl (C)
Fed
100
100
(287)
Η + cortisone
Fed
101
152
(287)
a (C) = control for the particular series of experiments.
rat treated with cortisone was not considered as significant whereas the
increase of this same enzymatic activity in the case of the hypophysectomized rat plus cortisone was considered to be significant by these same
workers.) In contrast to these results, Willmer (306) found that adrenalectomy of the rat decreases the activity of G-6-P DH, but does not alter
that of 6-PG DH. In vivo administration of either cortisone or corticosterone to these rats restores the activity of G-6-P DH to normal.
On fasting the hypophysectomized animal, however, a complicated
picture arises. First, such rats starved for 1 day decrease markedly both
hepatic dehydrogenase activities. On refeeding them, no significant rise
in either of the activities was observed. This is in sharp contrast to a
1-day fast of nonhypophysectomized rats which produces an increased
level of G-6-P DH and which at the end of 2 days of fasting reduced