Abstract
Infusion of adrenaline or noradrenaline in man gives rise to increases in plasma free fatty acid level through its indirect action on adipose tissue. Many kinds of psychological stresses have been shown to produce elevated plasma FFA levels. The present work aims to delineate some of the psychological and neurohumoral factors which mediate the external stress which leads to fat mobilization.
In 18 subjects FFA increase following stress was found to be due to a primary increase in FFA production rather than to diminished use. The effect of emotional stress on this phenomenon was found to be significantly less in the presence of beta adrenergic blockade (propanolol). Thus it was concluded that, a) the adipokinetic mechanism of short-term emotional arousal depends on endogenous catecholamine and, b) FFA mobilization under these circumstances is an indirect measure of catecholamine activity.
In two groups of 20 and 24 subjects levels of anxiety and three kinds of hostility were measured from unprompted verbalizations while blood was drawn for FFA determinations. FFA levels were found repeatedly to be positively and significantly correlated with anxiety levels, but not with hostility levels. Maximum FFA levels were found to develop 15 minutes after experimental stress. Even when greater amounts of hostility were provoked by stress interviews, no association between hostility and FFA level was found. The changes in FFA level in REM sleep were also found to be correlated positively and significantly with anxiety levels in 20 dream reports.
Further studies were done on nine subjects from whom blood was drawn for plasma free fatty acid determinations while they were asked under hypnosis to assume alternately a passive and an active approach to a task. In experiments in which the subject was instructed to be passive or active, much greater fat mobilization resulted than in experiments in which he was given no suggestion. The passive attitude stimulated somewhat more anxiety. With the suggestion to be passive and no suggestion, anxiety and FFA ceased to co-vary in the time lag relationship described above.
The significance of these findings for our beginning understanding of psycho-physiological mechanisms in diabetes mellitus, coronary disease and obesity were mentioned.