Absence of circadian rhythms of gonadotropin secretion in women
KM Klingman, EE Marsh, EB Klerman…�- The Journal of�…, 2011 - academic.oup.com
KM Klingman, EE Marsh, EB Klerman, EJ Anderson, JE Hall
The Journal of Clinical Endocrinology & Metabolism, 2011•academic.oup.comContext: Diurnal rhythms of LH and FSH have been reported in normal women, but it is
unclear whether these reflect underlying circadian control from the suprachiasmatic nucleus
and/or external influences. Objective: The aim of this study was to determine whether
endogenous circadian rhythms of LH, FSH, and the glycoprotein free α-subunit (FAS) are
present in reproductive-aged women. Design and Setting: Subjects were studied in the early
follicular phase using a constant routine protocol in a Clinical Research Center at an�…
unclear whether these reflect underlying circadian control from the suprachiasmatic nucleus
and/or external influences. Objective: The aim of this study was to determine whether
endogenous circadian rhythms of LH, FSH, and the glycoprotein free α-subunit (FAS) are
present in reproductive-aged women. Design and Setting: Subjects were studied in the early
follicular phase using a constant routine protocol in a Clinical Research Center at an�…
Context
Diurnal rhythms of LH and FSH have been reported in normal women, but it is unclear whether these reflect underlying circadian control from the suprachiasmatic nucleus and/or external influences.
Objective
The aim of this study was to determine whether endogenous circadian rhythms of LH, FSH, and the glycoprotein free α-subunit (FAS) are present in reproductive-aged women.
Design and Setting
Subjects were studied in the early follicular phase using a constant routine protocol in a Clinical Research Center at an academic medical center.
Subjects
Subjects were healthy, normal-cycling women aged 23–29 yr (n = 11).
Main Outcome Measures
Temperature data were collected, and blood samples were assayed for LH, FSH, FAS, and TSH.
Results
Core body temperature and TSH were best fit by a sinusoid model, indicating that known circadian rhythms were present in this population. However, the patterns of FSH, LH, and FAS over 24 h were best fit by a linear model. Furthermore, there were no differences in LH and FAS interpulse intervals or pulse amplitudes between evening, night, and morning.
Conclusions
Under conditions that control for sleep/wake, light/dark, activity, position, and nutritional cues, there is no circadian rhythm of LH, FSH, or FAS in women during the early follicular phase despite the presence of endogenous rhythms of TSH and core body temperature. These studies indicate that endogenous circadian control does not contribute to previously reported diurnal rhythms in reproductive-aged women and emphasizes the importance of environmental cues in controlling normal reproductive function.
Oxford University Press