Sexual Differentiation of Circadian Clock Function in the Adrenal Gland

Authors

Ian Kloehn, Marquette University
Savin B. Pillai, Marquette University
Laurel Officer, Marquette University
Claire Klement, Marquette University
Paul J. Gasser, Marquette UniversityFollow
Jennifer A. Evans, Marquette UniversityFollow

Document Type

Article

Language

eng

Publication Date

5-2016

Publisher

Endocrine Society

Source Publication

Endocrinology

Source ISSN

1945-7170

Original Item ID

DOI: 10.1210/en.2015-1968

Abstract

Sex differences in glucocorticoid production are associated with increased responsiveness of the adrenal gland in females. However, the adrenal-intrinsic mechanisms that establish sexual dimorphic function remain ill defined. Glucocorticoid production is gated at the molecular level by the circadian clock, which may contribute to sexual dimorphic adrenal function. Here we examine sex differences in the adrenal gland using an optical reporter of circadian clock function. Adrenal glands were cultured from male and female Period2::Luciferase (PER2::LUC) mice to assess clock function in vitro in real time. We confirm that there is a pronounced sex difference in the intrinsic capacity to sustain PER2::LUC rhythms in vitro, with higher amplitude rhythms in adrenal glands collected from males than from females. Changes in adrenal PER2::LUC rhythms over the reproductive life span implicate T as an important factor in driving sex differences in adrenal clock function. By directly manipulating hormone levels in adult mice in vivo, we demonstrate that T increases the amplitude of PER2::LUC rhythms in adrenal glands of both male and female mice. In contrast, we find little evidence that ovarian hormones modify adrenal clock function. Lastly, we find that T in vitro can increase the amplitude of PER2::LUC rhythms in male adrenals but not female adrenals, which suggests the existence of sex differences in the mechanisms of T action in vivo. Collectively these results reveal that activational effects of T alter circadian timekeeping in the adrenal gland, which may have implications for sex differences in stress reactivity and stress-related disorders.

Comments

Published version. Endocrinology, Vol. 157, No. 5 (May 2016): 1895-1904. DOI. © 2016 by the Endocrine Society. Used with permission.

Recommended Citation

Kloehn, Ian; Pillai, Savin B.; Officer, Laurel; Klement, Claire; Gasser, Paul J.; and Evans, Jennifer A., "Sexual Differentiation of Circadian Clock Function in the Adrenal Gland" (2016). Biological Sciences Faculty Research and Publications. 504.
https://epublications.marquette.edu/bio_fac/504