It has been demonstrated that in healthy subjects during oral glucose tolerance test,
serum calcium declines, while urinary calcium excretion increases, even if there is
not a general agreement in this regard. The study was carried out in order to evaluate
the effects of glucose oral load on calcium homeostasis in eight healthy adult women,
also considering ionized calcium, plasma insulin and parathyroid hormone changes.
The results showed a decline of total and ionized serum calcium (p < 0.05 and p <
0.01, respectively; maximum of the decrease at time 120′), in parallel with the increase
of urinary calcium/creatinine ratio (p < 0.05). Serum glucose and insulin increase
(p < 0.0001 and p < 0.0005 respectively; maximum value at time 60′), while the parathyroid
hormone level decreases (maximum decline at time 120′, p < 0.01). No changes were
observed in fasting control subjects for all parameters considered. The changes of
these parameters with time suggest that the effects of glucose oral load on calcium
metabolism in healthy adult women may be the consequence of parathyroid hormone suppression
induced by acute hyperglycemia/hyperinsulinemia. The results confirm in vivo the PTH behaviour in vitro, on cultured bovine parathyroid cells, with high glucose concentration.
Key words
Calcium - Glucose - Insulin - Parathyroid Hormone - Healthy Women
