TY - JOUR
T1 - Sex differences in testosterone reactivity and sensitivity in a non-model gerbil
AU - Matas, Devorah
AU - Doniger, Tirza
AU - Sarid, Shani
AU - Asfur, Mustafa
AU - Yadid, Gal
AU - Khokhlova, Irina S.
AU - Krasnov, Boris R.
AU - Kam, Michael
AU - Degen, A. Allan
AU - Koren, Lee
N1 - Publisher Copyright:
© 2020 Elsevier Inc.
PY - 2020/5/15
Y1 - 2020/5/15
N2 - Although testosterone (T) is a key regulator in vertebrate development, physiology, and behaviour in both sexes, studies suggest that its regulation may be sex-specific. We measured circulating T levels in Baluchistan gerbils (Gerbillus nanus) in the field and in the lab all year round and found no significant sex differences. However, we observed sex differences in circulating T levels following gonadotropin-releasing hormone (GnRH) challenge and T implants in this non-model species. Whereas only males elevated T following a GnRH challenge, females had higher serum T concentrations following T implant insertion. These differences may be a result of different points of regulation along the hypothalamic-pituitary–gonadal (HPG) axis. Consequently, we examined sex differences in the mRNA expression of the androgen receptor (AR) in multiple brain regions. We identified AR and β-actin sequences in assembled genomic sequences of members of the Gerbillinae, which were analogous to rat sequences, and designed primers for them. The distribution of the AR in G. nanus brain regions was similar to documented expression profiles in rodents. We found lower AR mRNA levels in females in the striatum. Additionally, G. nanus that experienced housing in mixed-sex pairs had higher adrenal AR expression than G. nanus that were housed alone. Regulation of the gerbil HPG axis may reflect evolutionary sex differences in life-history strategies, with males ready to reproduce when receptive females are available, while the possible reproductive costs associated with female T direct its regulation upstream.
AB - Although testosterone (T) is a key regulator in vertebrate development, physiology, and behaviour in both sexes, studies suggest that its regulation may be sex-specific. We measured circulating T levels in Baluchistan gerbils (Gerbillus nanus) in the field and in the lab all year round and found no significant sex differences. However, we observed sex differences in circulating T levels following gonadotropin-releasing hormone (GnRH) challenge and T implants in this non-model species. Whereas only males elevated T following a GnRH challenge, females had higher serum T concentrations following T implant insertion. These differences may be a result of different points of regulation along the hypothalamic-pituitary–gonadal (HPG) axis. Consequently, we examined sex differences in the mRNA expression of the androgen receptor (AR) in multiple brain regions. We identified AR and β-actin sequences in assembled genomic sequences of members of the Gerbillinae, which were analogous to rat sequences, and designed primers for them. The distribution of the AR in G. nanus brain regions was similar to documented expression profiles in rodents. We found lower AR mRNA levels in females in the striatum. Additionally, G. nanus that experienced housing in mixed-sex pairs had higher adrenal AR expression than G. nanus that were housed alone. Regulation of the gerbil HPG axis may reflect evolutionary sex differences in life-history strategies, with males ready to reproduce when receptive females are available, while the possible reproductive costs associated with female T direct its regulation upstream.
KW - Androgen receptor
KW - GnRH challenge
KW - Testosterone implants
UR - http://www.scopus.com/inward/record.url?scp=85079037620&partnerID=8YFLogxK
U2 - 10.1016/j.ygcen.2020.113418
DO - 10.1016/j.ygcen.2020.113418
M3 - Article
C2 - 32027878
AN - SCOPUS:85079037620
SN - 0016-6480
VL - 291
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
M1 - 113418
ER -