Adrenal Hormones and Amine Metabolism in Alcoholism

Transcription

1 Adrenal Hormones and Amine Metabolism in Alcoholism VICTOR J. SCHENKER, PH.D.,* BENJAMIN KISSIN, M.D., LAURENCE S. MAYNARD, M.D.,t and ANNE C. SCHENKER, B.Sc* Previous studies in alcoholic patients and normal control subjects demonstrated a characteristic increase in urinary tryptamine after acute ingestion of ethanol. This response could be attributable only in part to monoamine oxidase (MAO) inhibition, verified by in vitro experiments. Evidence for an amine-releasing action of ethanol (suggestive but not conclusive in man) indicated a possible mechanism to account for this discrepancy. Other studies, conducted separately on a similar population, indicated activation of adrenocortical function by acute ingestion of ethanol. Similarly, activation of the sympathoadrenal system was suggested by increased excretion of epinephrine after ethanol. Present experiments were done to explore the possibility of adrenal activation being related to increased amine excretion seen with tryptamine after ethanol. Patients injected with 100-mg. hydrocortisone failed to show any demonstrable changes in urinary amines. Injection of epinephrine was followed by changes in urinary amines similar to those found with ethanol. These preliminary findings suggest further approach to question of amine-releasing action of ethanol. AHE STUDY of endocrine and bio- the biogenic amines including epinephchemical factors in alcoholism in this rine, the major hormone of the adrenal laboratory has been directed toward the medulla. Examined separately, our findexamination of the acute effects of etha- ings with respect to the effect of the nol upon adrenocortical function and, amines upon adrenocortical activity have more recently, upon the metabolism of indicated a change in the direction of increased activity. For example, we were From the Biochemical Research Section, De- able to demonstrate that acutely intoxipartment of Psychiatry and the State Univer- cated alcoholics with delirium tremens sity Alcoholism Clinic State University of haye significantly higher ] evels of plasma New York, Downstate Medical Center, Brook- T^^TT.. -J..if TJ ^- 11 lyn, New York 17-OH corticoids than did partially re- Supported by Grants MH and MH- habilitated alcoholic patients. 1 These in from the U. S. Public Health Service, turn showed higher levels than those Present address: Psychiatry and Aging Re- reported in the literature for normal search Laboratories, Veterans Administration contro]s. 2 Furthermore, ingestion of Hospital, Albany, N. Y.,,,, j 1 tpresent address: Department of Entomol- ethanol by alcoholics was associated With ogy, College of Agriculture, University of increased levels ot 17-OH corticoids in Arizona, Tucson, Ariz. the plasma. 3 With respect to the bio- 564

2 SCHENKER ET AL. 565 genie amines, epinephrine is perhaps the most noteworthy example of substances indicating increased activation of the sympathoadrenal system as an acute effect of ethanol ingestion. This is illustrated by the marked increase in urinary excretion rate of epinephrine following challenge with ethanol in alcoholic patients. This finding is in accord with that of Perman 4 in nonalcoholic subjects, and in part with the study in dogs by Klingman and Goodall 5 and that of von Wartburg et al. in rats. 6 These studies in animals demonstrated a rise in both epinephrine and norepinephrine after ethanol challenge. In our tests with alcoholics, as well as those of Perman in normal subjects, no significant increase in norepinephrine was elicited by ethanol. This acute effect of ethanol in producing increased excretion rates of amines is not confined to the catechol compounds. As shown in Table I, tryptamine excretion is also markedly increased in response to ethanol challenge. This finding, first observed by us in studies to be published elsewhere, 7 is of particular relevance to this presentation, which will describe some experiments aimed at the elucidation of the question of how ethanol elicits the observed increases in urinary excretion rate of amines, and, because we are dealing here with the metabolism of compounds known to be participants in producing the behavioral changes seen after administration of various psychotropic drugs, what such changes mean in terms of the behavioral effects of ethanol. This aspect of our findings with respect to tryptamine is more fully discussed in the report referred to above. 7 Briefly stated, our interest in the marked increase in urinary tryptamine following ethanol lay primarily in the similarity of this change in amine excretion after ethanol with that which characterizes many (but not all) of the drugs known to elevate mood, i.e., antidepressants. The increase in urinary amines in the case of such drugs is due to their inhibitory action upon monoamine oxidase. Although the causal relationship between this chemical property and clinical effect has by no means been established, there are some indications that monoamine oxidase (MAO) inhibition may be associated with central excitation. MAO inhibition by ethanol, however, could not in itself account for the increases in urinary tryptamine. This was demonstrated by our in-vitro studies in mouse liver homogenates, which disclosed MAO inhibition by ethanol to be in the order of 25-30%. s Similarly, in our studies in patients in whom a high level of MAO inhibition was induced by treatment with isocarboxazid resulting in a fivefold sustained increase in urinary tryptamine, ethanol challenge resulted in a still higher value: i.e., ethanol elicited its effect even in the face of marked MAO inhibition. In seeking further for an explanation of this phenomenon, we turned to the possibility of an aminereleasing action for ethanol. This seemed plausible, first from the point of view of reports in the literature describing the TABLE 1. MEAN TRYPTAMINE RESPONSES (MGM./HR.) AFTER ETHANOL CHALLENGE AND WATER-CONTROL DRINKS IN PLACEBO-TREATED ALCOHOLICS AND CONTROL SUBJECTS Mean tryptamine excretion over 4 hr. After ethanol After water control Alcoholics 5.36 (22) 2.92 (22) p <.01 Controls 6.97 (12) 4.61 (7) p <.05 p<.05 p >.05 <.06 VOL XXVIII, NO. 4 (PART II), 1966

3 566 HORMONAL EFFECTS release of serotonin by ethanol from various tissues in animals 0 ' 10 a finding, however, about which there is still some disagreement and second, from a consideration of the clinical behavioral facts with respect to the effects of ethanol ingestion. It is well known that ethanol does not produce mood elevation in all people, as might be expected were the action of this compound entirely one of MAO inhibition. In fact, many individuals experience quite the opposite: tranquilization or even depression. The notion, therefore, of a dual action of ethanol one of MAO inhibition, the other of amine-release would fit the facts much more satisfactorily both from the biochemical and the clinical point of view, for the release of amines in the presence of even moderate MAO inhibition such as we found might conceivably account for the high urinary rate of excretion of amine after the ingestion ethanol. From the behavioral point of view, the amine-releasing properties of tranquilizers such as reserpine, and in some instances, chlorpromazine, suggest an explanation for the different and varied changes in behavior seen after ethanol. Thus far we have been unable to provide any convincing evidence for an amine-releasing action for ethanol in man. Quite recently, however, we have conducted exploratory experiments examining the extent to which there might be an interaction between the effects of ethanol upon adrenal function, both cortical and medullary, such as those referred to above, and the changes in amine metabolism as reflected in changes in urinary levels of tryptamine. Specifically, these experiments comprise the examination, in a small number of alcoholic patients and nonalcoholic control subjects, of the acute effects of parenterally administered adrenal hormones, epinephrine and hydrocortisone, upon the excretion rates of tryptamine and the three catecholamines epinephrine, norepinephrine, and dopamine, with a comparison in turn with our previous findings with ethanol. Methods Experimental Subjects A total of 3 alcoholic patients and 4 control subjects were tested. The alcoholics were male patients selected from the psychiatric wards of the Kings County Hospital and Psychiatric Center. They were tested approximately 5 days after admission to hospital following upon an acute alcoholic bout. All underwent physical and neurological examination to exclude illness other than chronic alcoholism. All medication, except for 1.5-gm. Seconal given at bedtime on the day previous to testing, was discontinued for at least 24 hr. before the experiment was begun. The control subjects comprised 4 healthy young men: 3 medical students and 1 laboratory worker. All were screened medically prior to participation in the experiment. Test Procedure The experimental test procedure followed was the same as that standardized in our previous studies with ethanol challenge. All subjects were tested in the fasting state at bed rest in a semirecumbent position. Each experimental period consisted of 3 consecutive days spent under identical conditions except for the test substance injected thus: Day 1, physiological saline; Day 2, adrenaline (0.3 ml. of a 10 ~ H solution); Day 3, hydrocortisone (2 ml. of hydrocortone phosphate, equivalent to 100 mg. of hydrocortisone). All three substances were given by the intramuscular route. Testing began at 8:00 A.M., when the subjects were instructed to empty their bladders completely; about 250 ml. of tap water was taken at this time. One hour later, the subjects were again instructed to void completely, and the 1-hr, preinjection specimen collected. At this time the respective test solutions were injected and water taken as before. Urine was subsequently collected at 1, 2, and 4 hr. after injection. All specimens were frozen at PSYCHOSOMATIC MEDICINE

4 SCHENKER ET AL C. within a few minutes after collection, pending chemical analysis. The analytic procedures for the estimation of free urinary amines were: tryptamine (Sjoerdsma et al. 11 ), urinary catecholamines, epinephrine, norepinephrine, and dopamine (Drujan et al. 1 -). Results and Discussion In Table 2 are shown the mean urinary excretion rates of the four biogenic amines measured over intervals of 1, 2, and 4 hr. after injection of saline, adrenaline, and hydrocortisone in the 3 alcoholic patients and 4 control subjects tested. In Table 3 are shown, for comparison, the corresponding values in the same amines following ethanol ingestion in 12 alcoholic patients previously studied. Inspection of these data shows primarily that of the two compounds injected, epinephrine is by far the more active in the acute production of changes over control values in excretion rate of the four amines measured. This appears to apply to both the alcoholic patients and the control subjects. Thus, in contrast to hydrocortisone, epinephrine elicits a marked rise in the rate of excretion of tryptamine, epinephrine, and dopamine, and a marked fall in that of norepinephrine. Comparison of this pattern of changes with that seen after ethanol in alcoholics (Table 3) discloses a noteworthy similarity in all respects save norepinephrine, which, after ethanol, does not fall precipitously but rather remains relatively unchanged. Hydrocortisone, on the other hand, has no effect whatsoever upon tryptamine and little, if any upon the catechols. Although one cannot draw conclusions from so small a number of subjects as in these experiments, there are a few comparisons between the alcoholics and the controls that might bear mentioning. One of these is the consistently higher values with saline control in the non- alcoholic subjects in all of the urinary amines except epinephrine. Although at this time we have no valid explanation of this difterence, it is worth considering in the evaluation of the relative degree of change in these two groups of subjects following challenge with ethanol or epinephrine. Actually, the differences in respective excretion rates after challenge are far less than those seen with saline control, again with the exception of the urinary epinephrine, where the effect of epinephrine challenge is far greater in the control subjects than in the alcoholics. This would indicate that in the case of tryptamine, norepinephrine, and dopamine, the absolute responses to epinephrine challenge are much greater in the alcoholics than in the controls. These differences might become useful in the characterization of alcoholics with respect to reactivity to sympathoadrenal activity. In conclusion it may be said that these exploratory experiments have provided some useful information regarding the questions posed earlier. Thus, with respect to an interrelationship between adrenocortical activity and the changes in amine metabolism under consideration, it appears unlikely that the effects of the acutely raised plasma corticoids associated with ethanol challenge participate significantly in producing the changes in amine excretion rates observed after ethanol.* What does seem interesting, however, is the effect of simulated sympathoadrenal stimulation by the injection of epinephrine, which, even at the small dose level used in these experiments, produces changes in the excretion rates of tryptamine, epinephrine, and dopamine which qualitatively so closely resemble the effect of This preliminary conclusion is being reexamined in light of the more recent report of "Wurtnmn and Axelrod 13 showing increased production of epinephrine in the rat adrenal after 6 days of treatment with the synthetic glucocorticoid Dexamethasone. VOL. XXVIII, NO. 4 (PART II), 1966

5 TABLE 2. MEAN URINARY EXCRETION RATES OF TRYPTAMINE AND CATECHOL AMINES AFTER INJECTION OF SUBSTANCES IN ALCOHOLICS AND NONALCOHOLIC CONTROLS Urinary amines Subjects* Tryptamine Alcoholics (/tg./hr.) Controls Epinephrine Alcoholics (/ig./hr.) Controls Norepinephrine Alcoholics (/ig./hr.) Controls Dopamine Alcoholics (j"g./hr.) Controls Saline control Adrenalinf Hydrocorlisonef (hr.) (hr.) (hr.) <.01$ <.01% *3 alcoholics, 4 controls. f-0.3 ml. 1/000 adrenalin solution, intramuscular injection: 2.0 ml. hydro^ortone phosphate (equivalent to 100 mg. hydrocortisone) intramuscular injection. Jin the presence of disproportionately high epinephrine concentrations, these norepinephrine values are beyond the sensitivity of the method of analysis used. TABLE 3. MEAN URINARY EXCRETION RATES OF THYPTAMINE AND CATECHOL AMINES AFTER CHALLENCE WITH ETHANOL DRINK AND WATER CONTROL IN ALCOHOLIC PATIENTS Tryptamine Epinephrine Norepinephrine Dopamine (hr. after drink) (hr. after drink) (hr. after drink) (hr. after drink) Condition After ethanol (^g./hr.) After water control 5.42* 6.03t 6.03t 1.31f 1.18% N = 12. *p <.03. tp <.01. tp <.001.

6 SCHENKER ET Al. 569 ethanol. One notion that might be ventured at this point is the possibility that ethanol might have an amine-releasing effect at least within the first few hours after its ingestion in view of its ability to stimulate the sympathoadrenal system (which is known to be involved particularly in conditions of psychological stress). Summary Preliminary experiments were conducted in alcoholic patients and nonalcoholic control subjects to examine the effects of injected hydrocortisone and of epinephrine upon the urinary excretion rates of tryptamine and catecholamines, in order to examine the possible participation of these adrenal hormones in producing the changes in urinary excretion rate of amines following challenge with ethanol. Comparison of the effects of these adrenal hormones with those previously found after ethanol ingestion upon urinary amines disclosed a qualitative similarity between epinephrine and ethanol. Hydrocortisone showed no noteworthy effects at the dose level used in these experiments. The significance of these preliminary findings toward elucidating the question of mechanism of changes in amine excretion after ethanol is discussed. Psychiatry and Aging Research Laboratories Veterans Administration Hospital, 151-H Albany, N, Y References 1. KISSIN, B., SCHENKER, V., and SCHEN- KER, A. C. Adrenal cortical function and liver disease in alcoholics. Amer ] Med Set 238:344, ELY, R. S., BRAY, P. F., RAILE, R. B., and KEIXY, V. C. Studies of 17-OH corticoids. V. Responses of 17 OH corticoids, eosinophils and glucose to ACTH and epinephrine. J Clin Invest 33:1587, KISSIN, B., SCHENKER, V., and SCHEN- KER, A. C. The acute effect of ethanol ingestion on plasma and urinary 17- OH corticoids in alcoholic subjects. Amer } Med Sci , PERMAN, E. S. The effect of ethyl alcohol on the secretion from the adrenal medulla in man. Ada Physiol Scand 44:241, KLINGMAN, G. I., and GOODALL, MCC. Urinary epinephrine and levarterenol excretion during acute sublethal alcohol intoxication in dogs. J Pharmacol 121:313, VON WARTBURG, J. P., BERLI, W., and AEBI, H. Der Einfluss langdauernder Aethylalkoholbelastung auf die Katecliolaminausscheidung in Harn der Ratte. Heh Med Acta 28:89, SCHENKER, V., KISSIN, B., MAYNARD, L. S., and SCHENKEH, A. C. The Effects of Ethanol on Amine Metabolism in Alcoholism. Pergamon Press, New York. In press. 8. MAYNARD, L. S., and SCHENKER, V. Monoamine oxidase inhibition by ethanol in vitro. Nature 196:575, WESTERFELD, W. W., and SCHULMAN, M. P. Some biochemical aspects of the alcohol problem. Quart ] Stud Alcohol 20:439, GURSEY, D., and OLSON, R. E. Depression of serotonin and norepinephrine levels in brain stem of rabbits by ethanol. Proc Soc Exp Biol 104:280, SJOERDSMA, A., OATES, J. A., FALTZ- MAN, P., and UDENFRIEND, S. Identification and assay of urinary tryptamine. / Pharm Exp Therap 126:217, DRUJAN, B. D., SOUHKES, T. L., LAYNE, D. S., and MUHPHY, G. F. The differential determination of catecholamines in urine. Canad. J Biochem Physiol 37: 1154, WURTMAN, R. J., and AXELROD, J. Adrenaline synthesis: control by the pituitary gland and adrenal glucocorticoids. Science 250:1464, VOL. XXVIII, NO. 4 (PART II), 1966