PTH and Hypoglycemia: Bone turnover was decreased along with PTH in a previous study employing the hypoglycemic clamping technique (4), suggesting that short-term alterations to bone turnover are due to direct effects of hypoglycemia (glucose concentrations were clamped at 2.5 mmol/l for 105 min) on bone cells or are mediated by changes in regulatory hormone concentrations triggered by hypoglycemia (4).