Effect of body posture on the serum potassium response to glucose in healthy subjects, diabetics and hyperthyroid patients

: Administration of glucose induces normally a decrease in serum potassium, though exceptionally a paradoxcial increase (PGIH) may occur. The effect of posture on glucose-induced serum potassium changes in health and disease has not been previously studied. We have investigated the influence of changes in body posture on the different serum potassium responses to glucose in various groups of 47 subjects. We have found a smaller decrease in serum potassium in the upright position than in the recumbent one in 20 healthy subjects and in 12 non-insulin dependent diabetics, but no significant difference in hyperthyroidism. The variable effect of posture on glucose-induced insulin secretion in the various groups of subjects did not provide explanation for the postural inhibition of the normal serum potassium response to glucose. A tendency to PGIH was found in a small number of diabetics. Although PGIH was completely reversed by DOC the normal postural difference between serum potassium curves was uneffected. It was concluded that change in the body posture has a definite influence on the glucose-induced decrease in serum potassium in normal people and is not mediated by insulin and/or aldosterone; PGIH develops in the upright position more easily than recumbency; exact serum potassium changes after glucose loading can be explored only by adequate standardization and carrying out both recumbent and upright measurements.