Blunted day-night changes in luteinizing hormone pulse frequency in girls with obesity: The potential role of hyperandrogenemia

Abstract

Context: Puberty is marked by sleep-associated changes in LH pulse frequency and amplitude. Early pubertal girls with obesity exhibit blunted day-to-night changes in LH secretion; whether this occurs in late pubertal obese girls is unknown. Objective: The objective of the study was to test two hypotheses: 1) blunted day-to-night changes in LH secretion occur in both early and late pubertal obese girls, and 2) such alterations are specifically associated with hyperandrogenemia. Design: This was a cross-sectional analysis. Setting: The study was conducted at a clinical research center. Patients or Other Participants: Twenty-seven early pubertal, premenarcheal girls (12 ofwhomwere obese) and 63 late pubertal (postmenarcheal) girls (27 of whom were obese) participated in the study. Intervention: Blood samples were taken every 10 minutes from 7:00 PM to 7:00 AM. Main Outcome Measure: Change in LH pulse frequency [LH interpulse interval (IPI)] from daytime hours (7:00 PM-11:00 PM, while awake) to nighttime hours (11:00 PM to 7:00 AM, while generally asleep). Results: Both nonobese and obese postmenarcheal girls demonstrated significant day-to-night decreases in LH pulse frequency (IPI increases of 33% and 16%, respectively), but day-to-night changes were blunted in obese girls (P