Biochemical Pharmacologv, 1958,Vol. 1,pp. 232-240, Pergamon Press, Ltd., London

SHORT COMMUNICATIONS

Reserpine depletion of adenosine triphosphate from the rat suprarenal medulla (Received 13 August 1958)

RESERPINE interferes with oxidative phosphorylation in rat brain and liver in vivo but has little effect on oxidative phosphorylation in skeletal muscle or heart.’ Studies in vitro have shown that reserpine reduces the P/O ratio in rat brain mitochondria by about 40 per cent2

A number of reports3y 4 have shown that reserpine depletes the brain and adrenal medulla of catechol amines. Since the adrenal medulla contains not only catechol amines but also a high conccn- tration of adenosine triphosphate (ATP),S> 6 It seemed of interest to investigate whether reserpine had an effect upon the adenosine nucleotides of the rat adrenal medulla. If a relationship exists between adrenal adenosine nucleotides and synthesis or storage of catechol amines,‘, a then reserpine which depletes the medulla of catechol amines should also affect the nucleotides.

Experiments were carried out using groups of 9 female rats, each rat weighing about 200 g. The control groups were injected with an appropriate volume of the vehicle, while the treated groups were given 1 mg of reserpine by intraperitoneal injection. Food was withheld and the animals were killed 16 hr after the injection.

The adrenal medullae were carefully dissected out and crushed in a centrifuge tube containing 1 ml of 1.5 per cent perchloric acid. A sandpaper-roughened glass rod and a little silver sand facilitated crushing. The adrenal medullae from each group of rats were pooled. All operations were carried out at 0”. The crushed samples were centrifuged at 2000 r.p.m. for 10 min, the supernatant transferred and the residue extracted twice with 1 ml of 15% perchloric acid. An equivalent amount of succinate buffer (pH 6.1) using a pH meter. The final volume was adjusted to 10 ml with succinate buffer.

Total catechol amines were estimated on the blood pressure of the spinal cat and calculated in noradrenaline equivalents. Adenosine nucleotides were estimated by the specific enzymic method of Kalckar.9

The results are presented in Table 1.

TABLE 1. EFFECTSOFRESERPINEONTHECONTENTOFCATECHOLAMINESANDATPOFTHEADRENALMEDULLA

Group Treat- Wt. of pooled Total catechol amines No.* ment medullae in noradrenaline

(mg wet wt) (equiv.mg/g wet wt) (expressed in rmoles/g wet wt)

: Control 29.5 11.7 Control 29.7 12.15

3 Reserpine 39.1 2.90 4 1 (1 q)

Reserpme 39.9 2.10

(1 mg)

* Each group contains 18 medullae taken from 9 rats.

It is clear that reserpine depletes the medulla both of catechol amines and ATP. No adenosine diphosphate (ADP) and little adenosine monophosphate (AMP) are found in the adrenal medullae of the drug-treated animals, i.e. there is no increase in the concentration of these compounds over the

232

Short Communications 233

control level as might have been expected. The fact that the c&echo1 amines and ATF disappear in roughly the same proportions during resetpine treatment may point to a specific role for ATP in the starage or release of catecho amines, In a recent publication SchiimannlG has obtained similar results in the hen. Departmtlnr of Materia Medica and S. M. KIRPIXAR* Xhera~eat~cs and ~e~~t~&~t of ~ioc~e~~st~.~, G. A. J. GOODLAD~ The uFt&mit.Y, Glasgow, w.2 J. J. LEWXs

* Squibb Fonndat~on Fellow. t Beit Memorial F&low,

REFERENCES 1. S. M. KmPeroZr7 and J. J. Lnwrs (i?r press). 2, L. J. AWOD and K. L. ROMANCZ~FJR, Ann. N. Y. Acad. Sci. 66, 812 (1957). 3. M. HO~ZBAUER and M. Voor, .r. Ne~r~~~~~. X,8 (f956), 4, A, CARISON and N.-A. HILLARP, $2. Fysiogr. Salk Land FWJ. 26, 1 (1956), 5. H. BLAS~WKD, G. V. R. BORN, A. D.“~ORIO and N. R. EADE, Siochem. J. $2, LgP (1956). 6. N.-A. HICLARP, B. HOGBERG and B. NILSON, Nature, Land. 176, 1032 (1955). 7. A. CARLSSC~N and N.-A. HILLARP, Acta Physiol. Band. 37, 235 (1956). 8. A.CARLSSON, N.-A. HIUARP and 13. HOCKFELT,& Viol. Chem. 227,243 (X957). 9.H. M. KALCKAR,~. BioL Chevrr. 167,445 (1!%7), 10. H. J. SCR~_%MANN, Arch, Exp. Path. ~~a~~na~. 223, 237 (1958).

DANS des travauz rkents,l* s,a nous avons montrc! que la S-azaguanine dissocie la synth&e des acides n~cl~iqn~ de celie des protkines chez B~c~~~~s CXWW, dune facon qui rappello & plusieurs points de vue les effets de la chloromy~t~ne sur ~sc~~~~c~~a co&. Par exempLe, l’azaguanine, comme la cbloro- myc&ine, inbibe fortement la synthkse des prot&_nes sans en&aver celfe des patois ceWaire~,~* 3

Mandeld a observe de son c&i: que ~inco~orat~on des acides amines contena~t du soufre est inhi& tandis que celie de i’acide g~ut~ique ne le serait pas. Ceci indiquerait que la composition des prut&es form&s en prksence d’azaguanine est anoxmale.

Nous crayons que le choix de l’acide glntamiqne cornme pr&curseur marqui: dans de teks experiences est ~ret~ble, car wt acide amiuk s’incorpore non se&enter& dans fes prot&ms mais encore dans ks parois ceifulaires de B, CP~~US, dent la synth&se nest pas inhibke par ~a~~a~ne.l~ 3 11 est certain que l’incorporation d’acide giutamique observke par Mandel correspond pour une Large part Q la croissance des patois celh.tLaires.

Toutefois, des rksultats dune tout autre nature indiquent que la synthese rksiduelle observk en presence d’azaguanine pourrait en effet’ correspondre & la formation de substances prot&ques anormales. Nous avons signah? que la syntMse de penicillinase, enzyme constitutif dans la souche W&&e, eat plus fortement inhibQ que X’incorporation de m&hionine-% dans les proteines. En outre, si Ia synth&se des proteines est inhib6e par l’azaguanine (40 pg/m!) chez B, cereas en croissance exponentieile et que de Ia ~anos~ne soit jot&e au syst&me 60 min apres l’analogue, ~inc~~o~t~on de ph~nylaIan~e-~~C dans ks protkines et la synth&se de p~n~cilIjna~ sont to&s deux &tab&s, mais pas sinu&anClment. 11 s'hcoule 2 heures entre le moment ou l’incorporation de ph&tylalanine reprend et c&i o& la syntb&e de p&Glfinase se r&ablit (Fig. I ).

A moins que la p&nicilSmase oonstitutive ne se comporte autrement que la &part des prot&ues de Ia bactkie, tout permet de penser que ~in#~~t~on de pb~nyIa~~~ne qui est r&balie par la guano&e ne repnkente pas dts le d&but la syntl&e de proteines parfaites.

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