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


METHODS
This was a cross-sectional analysis.


METHODS
The study was conducted at a clinical research center.


METHODS
Twenty-seven early pubertal, premenarcheal girls (12 of whom were obese) and 63 late pubertal (postmenarcheal) girls (27 of whom were obese) participated in the study.


METHODS
Blood samples were taken every 10 minutes from 7:00 pm to 7:00 am.


METHODS
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 = .004, obese vs nonobese). Day-to-night LH pulse frequency decreased significantly in postmenarcheal obese subjects with normal T concentrations (26% IPI increase) but not in those with hyperandrogenemia. Similar differences were evident for LH pulse amplitude. Nonobese and obese early pubertal girls exhibited nonsignificant differences in day-night LH pulse frequency (day to night IPI increase of 26% vs decrease of 1%, respectively).


CONCLUSIONS
Day-to-night changes in LH pulse secretion are blunted in postmenarcheal obese adolescent girls. This phenomenon may in part reflect hyperandrogenemia.
The Center for Research in Reproduction (J.S.C., J.P.B., C.B.S., J.C.M., C.R.M.), Division of Endocrinology, Departments of Medicine (J.S.C., J.P.B., J.C.M., C.R.M.) and Pediatrics (C.B.S.), and Department of Public Health Sciences (J.T.P.), University of Virginia Health System, Charlottesville, Virginia 22908; and Division of Reproductive Endocrinology and Infertility (R.J.C.), Department of Reproductive Medicine, University of California, San Diego, San Diego, California 92103.
Jessicah S
JS
Collins
Jennifer P
JP
Beller
Christine
C
Burt Solorzano
James T
JT
Patrie
R Jeffrey
RJ
Chang
John C
JC
Marshall
Christopher R
CR
McCartney
D000293:Adolescent; D002648:Child; D002940:Circadian Rhythm; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D017588:Hyperandrogenism / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008572:Menarche / Q000097:blood; D009765:Obesity / Q000097:blood*; D011627:Puberty / Q000097:blood
D007986:Luteinizing Hormone