Microanalysis in Medical Biochemistry

Abstract

1126 thetic nerves, or through pituitary and adrenal hormonal secretions. The fact that daily creatinine excretion varied very little between periods of oliguria and polyuria when urine was very carefully collected (e.g., fig. 4) suggests a fairly steady glomerular filtration-rate. On the other hand, during oliguria both serum-sodium and packed-cell volume fell, indicating interruption of the normal regulation of blood tonicity through the hypothalamic posterior-pituitary system, while the sodium-potassium ratio in the urine also attained its lowest level (around 2) suggesting enhanced adrenal-hormone (aldosterone) secretion in this phase of the cycle. As for the polyuria of the other phase, recent work (Dingman et al. 1958) suggests that sharp rises in cortisol in the blood may produce diuresis and natriuresis, and some measurements of adrenal corticol function which will be reported later are consistent with this idea. Finally, are the body-fluid disturbances responsible for some of the mental symptoms ? Both sodium depletion (McCance 1936) and overhydration (Wynn and Rob 1954) can produce mental symptoms such as lethargy and depression in healthy subjects. Many patients, however, tolerate greater degrees of hyponatrasmia than were shown by case 2, without developing mental symptoms (e.g., see Schwartz et al. 1957); nor did dehydration alter this patient's symptoms. Loss of body-fluid was associated with depression in case 1, but heralded hypomania in case 2. With chlorpromazine treatment, however, the relationship between mental and physical symptoms was changed in the second patient, so that loss of body-fluid now went with depression. Clearly there can be no simple connection between the two. It is therefore more likely that here mental and physical signs both result from some deeper process, rather than that one causes the other. At the same time, not least because of Woodbury's (1958) demonstration that changes in cerebral excitability in rats can be induced by changes in steroids and electrolytes, the possibility must remain open that in some patients water and electrolyte disturbances may lie at the root of their illnesses. Summary A metabolic study of two chronic psychotic patients with recurring mental disturbances showed periodic losses and gains of bodyweight associated with particular phases of the mental illness, while food and fluid intake were steady. Weight loss was accompanied by polyuria with increased urinary excretion of sodium chloride, weight gain by oliguria and sodium retention. In one patient weight was lost at the beginning of an attack of depression, in the other it began just before emergence from a depressive semistuporose state and the start of a hypomania. In the second patient, who was studied in greater detail, the weight variation could be almost abolished by decreasing the sodium or water intake, without, however, grossly affecting the mental symptoms. Cyclic fluctuations were demonstrated in serum-sodium and packed-cell volume, relative hyponatrxmia and coincident greater hydration of the blood being observed just before the onset of each polyuric phase. Chlorpromazine treatment increased the total bodyweight , diminished the weight fluctuation in each cycle, modified the mental symptoms in each cycle without altering the rhythm, and shifted the time of weight and sodium loss to the onset of each depressive phase. Body-water changes (and hence bodyweight changes) may result from the central nervous disturbances occurring in some mental illness, probably through the hypothalamic-endocrine system.