Publication
Endogenous Circadian Regulation of Female Reproductive Hormones
Publisher:
The Endocrine Society
Date:
15-08-2019
DOI:
10.1210/JC.2019-00803
Abstract: Studies suggest that female reproductive hormones are under circadian regulation, although methodological differences have led to inconsistent findings. To determine whether circulating levels of reproductive hormones exhibit circadian rhythms. Blood s les were collected across ∼90 consecutive hours, including 2 baseline days under a standard sleep-wake schedule and ∼50 hours of extended wake under constant routine (CR) conditions. Intensive Physiological Monitoring Unit, Brigham and Women’s Hospital. Seventeen healthy premenopausal women (22.8 ± 2.6 years nine follicular eight luteal). Fifty-hour CR. Plasma estradiol (E2), progesterone (P4), LH, FSH, SHBG, melatonin, and core body temperature. All hormones exhibited significant 24-hour rhythms under both standard sleep-wake and CR conditions during the follicular phase (P 0.05). In contrast, only FSH and SHBG were significantly rhythmic during the luteal phase. Rhythm acrophases and litudes were similar between standard sleep-wake and CR conditions. The acrophase occurred in the morning for P4 in the afternoon for FSH, LH, and SHBG and during the night for E2. Our results confirm previous reports of ∼24-hour rhythms in many female reproductive hormones in humans under ambulatory conditions but demonstrate that these hormones are under endogenous circadian regulation, defined as persisting in the absence of external time cues. These results may have important implications for the effects of circadian disruption on reproductive function.