Melatonin‐dependent changes in neurosteroids are associated with increased aggression in a seasonally breeding rodent

2021 ◽  
Vol 33 (3) ◽  
Author(s):  
Kathleen M. Munley ◽  
Jonathan C. Trinidad ◽  
Jessica E. Deyoe ◽  
Catherine H. Adaniya ◽  
Andrea M. Nowakowski ◽  
...  
Keyword(s):  
Seasonally Breeding

Seasonal reproduction and gonadal function: A focus on humans starting from animal studies

2021 ◽  
Author(s):  
Ester Beltran-Frutos ◽  
Livio Casarini ◽  
Daniele Santi ◽  
Giulia Brigante
Keyword(s):  
Animal Studies ◽  
Current Knowledge ◽  
Seasonal Pattern ◽  
Human Reproduction ◽  
Gonadal Function ◽  
Functional Changes ◽  
Morphological Variations ◽  
Gonadal Atrophy ◽  
Main Regulator ◽  
Seasonally Breeding

Abstract Photoperiod impacts reproduction in many species of mammals. Mating occurs at specific seasons to achieve reproductive advantages, such as optimization of offspring survival. Light is the main regulator of these changes during the photoperiod. Seasonally breeding mammals detect and transduce light signals through extraocular photoreceptor, regulating downstream melatonin-dependent peripheral circadian events. In rodents, hormonal reduction and gonadal atrophy occur quickly, and consensually with short-day periods. It remains unclear whether photoperiod influences human reproduction. Seasonal fluctuations of sex hormones have been described in humans, although they seem to not imply adaptative seasonal pattern in human gonads. This review discusses current knowledge about seasonal changes in the gonadal function of vertebrates, including humans. The photoperiod-dependent regulation of hypothalamic–pituitary-gonadal axis, as well as morphological and functional changes of the gonads are evaluated herein. Endocrine and morphological variations of reproductive functions, in response to photoperiod, are of interest as they may reflect the nature of past population selection for adaptative mechanisms that occurred during evolution.

scholarly journals The neurogenomic transition from territory establishment to parenting in a territorial female songbird

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Alexandra B. Bentz ◽  
Douglas B. Rusch ◽  
Aaron Buechlein ◽  
Kimberly A. Rosvall
Keyword(s):  
Breeding Season ◽  
Neural Plasticity ◽  
Behavioral Plasticity ◽  
Critical Role ◽  
Regulatory Pathways ◽  
Expression Of Genes ◽  
Trade Offs ◽  
Glucocorticoid Signaling ◽  
Seasonally Breeding ◽  
The Brain

Abstract Background The brain plays a critical role in upstream regulation of processes central to mating effort, parental effort, and self-maintenance. For seasonally breeding animals, the brain is likely mediating trade-offs among these processes within a short breeding season, yet research thus far has only explored neurogenomic changes from non-breeding to breeding states or select pathways (e.g., steroids) in male and/or lab-reared animals. Here, we use RNA-seq to explore neural plasticity in three behaviorally relevant neural tissues (ventromedial telencephalon [VmT], hypothalamus [HYPO], and hindbrain [HB]), comparing free-living female tree swallows (Tachycineta bicolor) as they shift from territory establishment to incubation. We additionally highlight changes in aggression-related genes to explore the potential for a neurogenomic shift in the mechanisms regulating aggression, a critical behavior both in establishing and maintaining a territory and in defense of offspring. Results HB had few differentially expressed genes, but VmT and HYPO had hundreds. In particular, VmT had higher expression of genes related to neuroplasticity and processes beneficial for competition during territory establishment, but down-regulated immune processes. HYPO showed signs of high neuroplasticity during incubation, and a decreased potential for glucocorticoid signaling. Expression of aggression-related genes also shifted from steroidal to non-steroidal pathways across the breeding season. Conclusions These patterns suggest trade-offs between enhanced activity and immunity in the VmT and between stress responsiveness and parental care in the HYPO, along with a potential shift in the mechanisms regulating aggression. Collectively, these data highlight important gene regulatory pathways that may underlie behavioral plasticity in females.

scholarly journals Estradiol-dependent catecholaminergic innervation of auditory areas in a seasonally breeding songbird

2011 ◽  
Vol 34 (3) ◽  
pp. 416-425 ◽  
Author(s):  
Lisa L. Matragrano ◽  
Sara E. Sanford ◽  
Katrina G. Salvante ◽  
Keith W. Sockman ◽  
Donna L. Maney
Keyword(s):  
Seasonally Breeding ◽  
Catecholaminergic Innervation

Effects of supplementary food on the winter inhibition of reproduction in male and female four-striped field mice (Rhabdomys pumilio)

2005 ◽  
Vol 17 (4) ◽  
pp. 393 ◽  
Author(s):  
C. Jackson ◽  
R. T. F. Bernard
Keyword(s):  
Reproductive Activity ◽  
Reproductive Organs ◽  
Food Supplementation ◽  
Ovarian Activity ◽  
Eastern Cape ◽  
Additional Food ◽  
Male And Female ◽  
Supplementary Food ◽  
Rhabdomys Pumilio ◽  
Seasonally Breeding

The effects of winter food supplementation on reproduction in the seasonally breeding four-striped field mouse Rhabdomys pumilio were investigated at Mountain Zebra National Park in the Eastern Cape Province of South Africa. On both control and supplemented grids, reproductive activity in females was inhibited; no pregnant females were collected and juveniles were only present in the first winter month. The provision of additional food resulted in an increase in body mass and mass of the male and female reproductive organs. However, all males, from both grids, were spermatogenically active. Ovarian activity was not stimulated by the provision of additional food, but the development of the uterus was and the endometrium was thicker and more vascularised in mice from the supplemented grid than from the control grid. We conclude that seasonal reproduction in R. pumilio is controlled by the females, in which reproductive activity is inhibited in winter. However, the provision of supplementary food was not sufficient to override the reproductive inhibition.

Histoarchitecture and Δ5-3β hydroxysteroid dehydrogenase profile in ovaries of the non-pregnant, pregnant and lactating insectivorous rat-tailed bat, Rhinopoma microphyllum kinneari

2007 ◽  
Vol 57 (1) ◽  
pp. 97-114 ◽  
Author(s):  
Seema Trivedi ◽  
Suresh Bihari Lall
Keyword(s):  
Enzyme Activity ◽  
Annual Cycle ◽  
Steroid Hormone ◽  
Post Partum ◽  
Hydroxysteroid Dehydrogenase ◽  
Follicular Atresia ◽  
Ovarian Stroma ◽  
Thecal Cells ◽  
Hormone Biosynthesis ◽  
Seasonally Breeding

AbstractThe histoarchitecture and profile of Δ5-3β hydroxysteroid dehydrogenase were studied in an insectivorous seasonally-breeding microchiropteran, Rhinopoma microphyllum kinneari (rattailed bat) ovaries during non-pregnant, pregnant and lactation phases. Mid-sections of follicles and ova showed variation in their diameter (0.013-0.182 mm and 0.010-0.075 mm, respectively). Though dextral and sinistral ovaries are functionally equivalent, ovulation occurs only once (alternately from one ovary) in each annual cycle. An extroverted corpus luteum (0.792 mm) was observed in either the dextral or sinistral ovary of a pregnant R. m. kinneari. This exhibited two types of cells. Follicular atresia was pronounced in ovaries during these reproductive stages. No post-partum 'heat' was discerned. Δ5-3β HSDH is a crucial catalyst in steroid hormone biosynthesis and the reaction product indicates status of steroidogenesis in different follicle types. Differential Δ5-3β HSDH activity evident from reaction product staining in three reproductive states and in different ovarian components was seen. Consistent sites of enzyme activity were thecal cells and ovarian stroma. However, intensity varied in different reproductive states.

Effects of long-term continuous GnRH administration on the pituitary–gonadal axis in Eld's deer stags (Cervus eldi thamin)

1995 ◽  
Vol 73 (9) ◽  
pp. 1609-1619 ◽  
Author(s):  
S. L. Monfort ◽  
J. L. Brown ◽  
T. C. Wood ◽  
M. Bush ◽  
L. R. Williamson ◽  
...  
Keyword(s):  
Dose Group ◽  
Low Dose ◽  
High Dose ◽  
Fertile Period ◽  
Nonbreeding Season ◽  
Testosterone Secretion ◽  
High Doses ◽  
Seasonal Decline ◽  
Seasonally Breeding

Eld's deer stags (Cervus eldi thamin) (in groups of three) were continuously administered gonadotropin-releasing hormone (GnRH) in control, low, medium, or high doses (0, 20.1 ± 0.7, 83.3 ± 2.6, and 292.9 ± 4.9 ng∙kg−1∙d−1, respectively) via osmotic minipumps for ~80 d to investigate the potential for precociously reactivating the pituitary–testicular axis during the nonbreeding season. Secretory patterns of LH, FSH, and testosterone concentrations were qualitatively similar among treatments. However, in the low-dose group, basal LH and FSH concentrations were both increased (p < 0.05) and pituitary responsiveness to a superimposed GnRH challenge was augmented (p < 0.05) after 12 weeks of treatment compared with all other groups. Despite these endocrine changes, continuous low-dose GnRH administration was not effective for precociously inducing testicular activity in this seasonally breeding species. High-dose GnRH administration initially induced a transient increase in LH, FSH, and testosterone secretion and delayed, but did not prevent, the seasonal decline in spermatogenesis. After 6–12 weeks of high-dose GnRH administration, however, attenuated pituitary responsiveness appeared to delay the normal seasonal reactivation of the pituitary–gonadal axis. In conclusion, prolonged, continuous low-dose GnRH administration did not effectively translate into a precocious onset of testicular activity; therefore, this specific approach is unlikely to be useful for prolonging the fertile period in this seasonally breeding species.

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