Seasonal expression of KiSS-1 and the pituitary gonadotropins LHβ and FSHβ in adult male Libyan jird (Meriones libycus)

Analysis of gonadotrophin‐releasing hormone‐1 and kisspeptin neuronal systems in the nonphotoregulated seasonally breeding eastern rock elephant‐shrew (Elephantulus myurus)

“…Reproduction in this species does not appear to be a photoregulated phenomenon: neither the testes nor seminiferous tubules differ in size between short‐ and long‐day housed eastern rock elephant‐shrews (Medger et al, ). Nevertheless, the large increases in the density of kisspeptin‐ir processes in the RP3V and arcuate nucleus in the breeding season and the positive correlations between the density of those processes and gonadal mass seem in keeping with changes previously reported for reproductively photoresponsive species, namely increases in: kisspeptin mRNA expressing cell bodies in the AVPV and arcuate nucleus in male and female Syrian hamsters (Ansel et al, ; Revel et al, ), kisspeptin mRNA in tissue containing the AVPV and arcuate nucleus in male Libyan jirds (seasonally reproducing desert rodents; Boufermes et al, ), kisspeptin‐ir process density, kisspeptin‐ir cell bodies and kisspeptin mRNA expression in the arcuate nucleus in wild‐captured male jerboas (results for the AVPV were not reported; Janati et al, ; Talbi et al, ), kisspeptin‐ir cell bodies in the AVPV (but not in the arcuate nucleus) in male and female Siberian hamsters (Greives et al, ; Mason et al, ) and kisspeptin‐ir cell bodies in the arcuate nucleus in ewes, female Abedeh goats (an Iranian seasonally breeding ecotype), and male and female red deer (Barrell et al, ; Jafarzadeh Shirazi et al, ; Smith et al, ). This peptide has also been studied in relation to the effects of social status, rather than season, on reproduction; in dominant, reproductively active female naked mole‐rats, the RP3V contains a greater number of kisspeptin‐ir cell bodies than in subordinate, reproductively suppressed animals of either sex (Zhou et al, ).…”

“…Research on several species indicates that reproductive development, whether the single irreversible process of puberty or the annual process seen in seasonal breeders (Ebling, ), is associated with activation of kisspeptin systems in both sexes (Barrell et al, ; Bentsen et al, ; Boufermes et al, ; Clarkson & Herbison, ; Greives et al, ; Han et al, ; Jafarzadeh Shirazi et al, ; Janati et al, ; Mason et al, ; Revel et al, ; Simonneaux et al, ; Smith et al, ; Takase et al, ; Talbi et al, ; Wagner et al, ). Under natural conditions, eastern rock elephant‐shrews show seasonal development of the gonads and, as previously reported (Medger et al, ), an associated rise in circulating testosterone and progesterone in, respectively, males and females.…”

A Kiss to drive rhythms in reproduction

“…ARC Kp neurons are known to coexpress neurokininB and dynorphin, and these two peptides in Syrian hamster (Bartzen‐Sprauer, Klosen, Ciofi, Mikkelsen, & Simonneaux, ) but only neurokininB in sheep (Weems et al., ) also exhibit seasonal changes driven by steroid‐dependant and steroid‐independent mechanisms. Further studies confirmed the occurrence of seasonal/photoperiodic variation in ARC Kp expression in a number of seasonal breeders, notably the Djungarian hamster (Greives et al., ; Rasri‐Klosen, Simonneaux, & Klosen, ), European hamster (Sáenz de Miera et al., ), Libyan jird (Boufermes et al., ), jerboa (Talbi, Klosen, Laran‐Chich, El Ouezzani, & Simonneaux, ), red deer (Barrell et al., ), and dromedary camel (Ainani et al., ) (Figure ). Surprisingly however, in some species like the Djungarian and European hamsters, ARC Kp expression is lower in sexually active LD‐adapted animals, and manipulating circulating sex steroids demonstrated that in these species the stimulatory effect of LD on Kp expression is overridden by a robust negative sex steroid feedback (Greives et al., ; Rasri‐Klosen et al., ; Sáenz de Miera et al., ).…”

Assessment of Testicular Lhcgr mRNA Expression Correlated with Testis and Seminal Vesicle Activities in the Libyan jird (Meriones libycus, Rodentia: Muridae) during Breeding Season Compared with Nonbreeding Season

“…These morphological characteristics reflected inhibition of spermatogenic and steroidogenic activities of the testis and correlated with changes in total testicular androgens and plasma testosterone levels [16]. In the viscacha (Lagostomus maximus), the testis, which is in the active phase in the summer and the nonbreeding period in the spring, showed similar morphological seasonal variations [21].…”

“…We previously reported that in the Libyan jird (Meriones libycus), a seasonal breeder, KiSS-1 expression was higher during the breeding season compared to nonbreeding season. Whereas LHβ and FSHβ expression levels were higher during the nonbreeding season in autumn and varied in an opposite manner with testicular and seminal vesicle weights and with plasma testosterone [16]. It seemed interesting to study the response to LH at the peripheral level and in particular the testicular level, where Leydig cells are the main LH target.…”