Fifteen patients with primary hyperparathyroidism due to parathyroid adenoma were subjected to an investigation on glucose and lipoprotein metabolism before operation and 3 and 12 months later.
Hypercalcaemia, hypophosphataemia and an increased urinary excretion of cyclic AMP were normalized after operation. The early insulin response to an iv glucose tolerance test was significantly lower after operation than before, but fasting serum-insulin levels did not differ. This change of the early insulin response was not reflected in any changes of the fasting blood-glucose concentration or the elimination rate of injected glucose.
Eleven of 15 subjects had increased levels of very-low-density lipoproteins before operation. The first change in lipoprotein concentrations after operation was a significant increase of high-density lipoproteins, occurring during the first 3 months. Only thereafter did the very-low-density lipoproteins decrease to normal values and concomitant the low density lipoproteins increase. As lipoprotein lipase activity of adipose tissue did not change after the operation it is assumed that the elevation of very-low-density lipoproteins before operation was caused by an increased production rate due to an increased lipolysis.
This sequence of events, primarily due to a disorder of the metabolism of the very-low-density lipoproteins, was reflected in the whole serum lipids only as an increase of the cholesterol but not the triglyceride concentration.