# Hypothalamic circuitry underlying the circadian control of sexual drive and reproduction

> **NIH NIH F32** · BETH ISRAEL DEACONESS MEDICAL CENTER · 2024 · $81,256

## Abstract

Physiological and biochemical processes in nearly every species (including humans) are regulated by the
circadian clock. For example, the reproductive system (of females) requires tight temporal organization of
estrogen-sensitive neural circuits that allows the hypothalamo-pituitry gonadal (HPG) axis to function properly.
In mammals, the body’s master pacemaker—the suprachiasmatic nucleus (SCN)—allows for coordination of
such neuroendocrine events to ensure that ovulation occurs at the time in which reproductive success can be
maximized. Evidence supporting the importance of proper clock function on fertility comes from several lines
of work demonstrating that misalignment of biological rhythms or disrupted function of the body’s master clock
(resulting from shift work, jet, lag, etc.) negatively impact reproduction—interfering with both male and female
fertility. Along these lines, knock-down of clock genes leads to impairments in fertility, and disruption of
circadian clock timing resulting from a reduction of sleep duration and/or architecture negatively impacts male
sex hormones and semen quality and leads to ovulatory deficiencies in females. Despite these well-
established observations that proper clock functioning is important to reproductive success, it is still unknown
whether a circadian rhythm exists in the propensity for sexual behavior and to what degree such a behavioral
rhythm may influence reproductive outcomes. Additionally, the neural circuits that mediate these behaviors as
a function of time-of-day have yet to be studied. Of note, it was recently shown that the propensity for
behavioral aggression follows a daily rhythm that is regulated by a circuit spanning the master clock (SCN), its
postsynaptic target the subparaventricular zone (SPZ), and the ventromedial hypothalamus (VMH).
Interestingly, the VMH has been shown to modulate both aggression and mating behaviors. Such results
suggest that this SCN—SPZ—VMH circuit may also mediate time-of-day dependent sexual behaviors. Hence,
this pathway may serve as a promising therapeutic target for the treatment of circadian dysfunction in people
experiencing idiopathic infertility. In this proposal, I will study how circadian clock time affects reproductive
behavior. I will first determine whether temporal overlap of male and female peak sexual behavior influences
reproductive success (Aim 1). I will also examine the hypothalamic circuitry that underlies the rhythm in sexual
behavior in mice (Aim 2), testing whether the first node of the pathway that regulates rhythms in aggression
(i.e. SCN—SPZ) also regulates rhythms in sexual behavior. Finally, using a chemogenetic approach, I will test
whether this hypothalamic circuit can be acutely manipulated to change sexual behavior levels across the day
(Aim 3). This work will test the hypothesis that the circadian rhythm in sexual behavior impacts conception and
that this drive is regulated by a similar circuit to that modulating aggression...

## Key facts

- **NIH application ID:** 10825135
- **Project number:** 1F32HD111339-01A1
- **Recipient organization:** BETH ISRAEL DEACONESS MEDICAL CENTER
- **Principal Investigator:** Sydney Elizabeth Aten
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $81,256
- **Award type:** 1
- **Project period:** 2024-09-01 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10825135

## Citation

> US National Institutes of Health, RePORTER application 10825135, Hypothalamic circuitry underlying the circadian control of sexual drive and reproduction (1F32HD111339-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10825135. Licensed CC0.

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