OBJECTIVES: To assess the impact of a levonorgestrel-releasing implant contraceptive (Norplant; Wyeth-Ayerst Laboratories, Philadelphia, PA) on glucose metabolism. DESIGN: Prospective evaluation of insulin action and secretion in women under hyperglycemic hyperinsulinemic clamp conditions in the midfollicular phase before and 8 weeks after Norplant placement. SETTING: Yale University Clinical Research Center. PARTICIPANTS: Seven previously normally cycling, nonobese, nondiabetic women participated in the study. INTERVENTIONS: Norplant insertion. MAIN OUTCOME MEASURES: Basal levels of glucose and insulin, as well as glucose-mediated insulin secretion, glucose uptake, and tissue sensitivity to insulin were assessed using the hyperglycemic hyperinsulinemic clamp technique before and after Norplant insertion. RESULTS: Norplant placement did not alter the fasting glucose or insulin levels. However, it was associated with a significant 37% increase in the first phase insulin response from a control level of 51 +/- 8 to 70 +/- 10 microU/mL (conversion factor to SI unit, 7.175), and a significant 48% increase in the second phase insulin response from 60 +/- 5 to 89 +/- 8 microU/mL. In association with this increase in insulin levels after Norplant insertion, total mean body glucose uptake (M) increased from 8.08 +/- 0.91 to 9.53 +/- 0.95 mg/kg per minute. However, when expressed as the total body glucose uptake per unit of insulin, the M:I ratio (a measure of tissue sensitivity to insulin) decreased significantly from a mean of 0.12 +/- 0.02 to 0.10 +/- 0.01 mg/kg per minute per microU/mL. CONCLUSION: Although Norplant insertion does not alter basal glucose and insulin levels, tissue sensitivity to insulin under hyperglycemic hyperinsulinemic conditions is decreased after Norplant insertion.
OBJECTIVES: To assess the impact of a levonorgestrel-releasing implant contraceptive (Norplant; Wyeth-Ayerst Laboratories, Philadelphia, PA) on glucose metabolism. DESIGN: Prospective evaluation of insulin action and secretion in women under hyperglycemic hyperinsulinemic clamp conditions in the midfollicular phase before and 8 weeks after Norplant placement. SETTING: Yale University Clinical Research Center. PARTICIPANTS: Seven previously normally cycling, nonobese, nondiabetic women participated in the study. INTERVENTIONS: Norplant insertion. MAIN OUTCOME MEASURES: Basal levels of glucose and insulin, as well as glucose-mediated insulin secretion, glucose uptake, and tissue sensitivity to insulin were assessed using the hyperglycemic hyperinsulinemic clamp technique before and after Norplant insertion. RESULTS: Norplant placement did not alter the fasting glucose or insulin levels. However, it was associated with a significant 37% increase in the first phase insulin response from a control level of 51 +/- 8 to 70 +/- 10 microU/mL (conversion factor to SI unit, 7.175), and a significant 48% increase in the second phase insulin response from 60 +/- 5 to 89 +/- 8 microU/mL. In association with this increase in insulin levels after Norplant insertion, total mean body glucose uptake (M) increased from 8.08 +/- 0.91 to 9.53 +/- 0.95 mg/kg per minute. However, when expressed as the total body glucose uptake per unit of insulin, the M:I ratio (a measure of tissue sensitivity to insulin) decreased significantly from a mean of 0.12 +/- 0.02 to 0.10 +/- 0.01 mg/kg per minute per microU/mL. CONCLUSION: Although Norplant insertion does not alter basal glucose and insulin levels, tissue sensitivity to insulin under hyperglycemic hyperinsulinemic conditions is decreased after Norplant insertion.
Authors: Julie A Womack; Rebecca Scherzer; Stephen R Cole; Kristopher Fennie; Ann B Williams; Margaret Grey; Howard Minkoff; Kathryn Anastos; Mardge H Cohen; Phyllis C Tien Journal: J Acquir Immune Defic Syndr Date: 2009-12 Impact factor: 3.731