This study is observational and no drugs or other interventions will be used. The population targeted in this study will be adult patients already on chronic hemodialysis with a diagnosis of secondary hyperparathyroidism. Experimental design will involve the use of a glucose clamp to maintain a constant, mild increase in blood glucose levels. Frequent, scheduled lab tests will be obtained during the period of hyperglycemia to evaluate phosphorous, calcium, and glucose levels and the relationship of any change in their values to changes in the parathyroid hormone level. The primary outcome will be to evaluate for any change in the parathyroid hormone level in the presence of hyperglycemia and to compare these results to that of our initial study