M. Sutters et al., CONTROL OF SODIUM-EXCRETION IN PATIENTS WITH CRANIAL DIABETES-INSIPIDUS MAINTAINED ON DESAMINO-[8-D-ARGININE]VASOPRESSIN, Clinical science, 85(5), 1993, pp. 599-606
1. We have studied the response of six patients with cranial diabetes
insipidus and six age-matched control subjects to dietary sodium restr
iction during constant administration of the synthetic vasopressin ana
logue desamino-[8-D-arginine]vasopressin. 2. Urine flow increased on t
he first low salt day in the normal control subjects but not in the pa
tients with cranial diabetes insipidus. Body weight fell 1.35 kg in th
e control subjects but was constant in the patients with cranial diabe
tes insipidus. 3. Urinary sodium excretion fell at the same rate in bo
th groups. Diurnal variation of urinary sodium excretion and creatinin
e clearance was present in the control subjects but not in the patient
s with cranial diabetes insipidus. 4. Changes in plasma sodium concent
ration and osmolality were similar. Plasma protein concentration incre
ased more in the control subjects (from 69.1+/-1.5 to 73+/-1.2 versus
from 71.7+/-1 to 73.2+/-1.1 g/l). The responses of plasma atrial natri
uretic peptide, plasma renin activity and salivary aldosterone concent
ration were similar between the two groups. Salivary aldosterone conce
ntration levels were consistently higher in the patients with cranial
diabetes insipidus. 5. We confirm that the low salt diuresis is trigge
red by release from the antidiuretic activity of arginine vasopressin.
In the patients with cranial diabetes insipidus extracellular fluid o
smoregulation appeared to be achieved by the movement of water out of
and sodium into the extracellular fluid. 6. Absent posterior pituitary
function and hypothalamic disturbances did not alter renal sodium con
servation. Total extracellular fluid sodium appeared to be lower in th
e patients with cranial diabetes insipidus than in the control subject
s. Disturbances of hypothalamic and pituitary function may have caused
resetting of overall sodium balance and altered diurnal cycles of uri
nary sodium excretion and creatinine clearance.