276
O. STRUBELT
cycles which increase metabolic rate by consumption of A TP depend on
the cooperation of musculature and liver or adipose tissue and liver, respectively, and therefore can take place only in the whole organism.
Sympathetic glycogenolysis and lipolysis are mediated by the formation
of cyclic 3',S'-AMP [5, 6]. Therefore, this compound should augment metabolic rate, too. However, in our experiments extrinsic 3',S'-AMP (50 and
100 mg/kg i.v.) failed to augment oxygen consumption of rats, perhaps as
2.8
2.6
OJ
82.4
:::::. c
E
::::- 2.2
E
2.0
°c
39.5
39.0
38.5
38.0
375
370
36.5
03mg/kg
Adrenaline
i.p.
* __ l~ ___ o!_ ' * * 9*
~ __ o- r
-0--0--~ ...... o
* ~o
* * ,l.! ... o'"
~---O---T
Rectal Temperature
+-e-._
.--.------e_1
!
e-e-.-.
I
30
o
30
60
90
120
min
Fig. 2. Oxygen consumption and rectal temperature of anesthetized rats after
0.3 mg/kg adrenaline i.p. at ambient temperatures of 28°C (e--e) and 32.5°C
(0--0). Means of 12 and 8 experiments, respectively. * = significant difference
to the simultaneous value of the other group
a consequence of its low permeation into tissues. Theophylline, on the
other hand, which inhibits destruction of 3',S'-AMP [5], proved to be a
potent calorigenic agent; the very slow onset of its action is compatible
with the idea that it exerts calorigenesis by accumulation of endogenous
3',S'-AMP.
References
1. ELLIS, S.: Pharmacol. Rev. 8,485 (1956).
2. GRIFFITH, F. R. JR.: Physiol. Rev. 31, 151 (1951).
3. HOLTZ, P., U. D. PALM: Ergebn. Physiol. 58 (1966).