scholarly journals Seasonal changes of androgen receptor, estrogen receptors and aromatase expression in the medial preoptic area of the wild male ground squirrels (Citellus dauricus Brandt)

2016 ◽  
Vol 60 (2) ◽  
Author(s):  
F. Zhang ◽  
J. Wang ◽  
Y. Jiao ◽  
L. Zhang ◽  
H. Zhang ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Estrogen Receptors ◽  
Breeding Season ◽  
Ground Squirrel ◽  
Preoptic Area ◽  
Medial Preoptic Area ◽  
Ground Squirrels ◽  
Mrna Levels ◽  
Wild Male ◽  
Significant Difference

<p>The wild ground squirrel is a typical seasonal breeder. In this study, using RT-PCR, western blot and immunohistochemistry, we investigated the mRNA and protein expressions of androgen receptor (AR), estrogen receptors α and β (ERα and ERβ) and aromatase cytochrome P450 (P450arom) in the medial preoptic area (MPOA) of hypothalamus of the wild male ground squirrel during the breeding season (April), the non-breeding season (June) and pre-hibernation (September). AR, ERα, ERβ and P450arom protein/mRNA were present in the MPOA of all seasons detected. The immunostaining of AR and ERα showed no significant changes in different periods, whereas ERβ and P450arom had higher immunoreactivities during the breeding season and pre-hibernation when compared to those of the non-breeding season. Consistently, both the protein and mRNA levels of P450arom and ERβ were higher in the MPOA of pre-hibernation and the breeding season than in the non-breeding season, whereas no significant difference amongst the three periods was observed for AR and ERα levels. These findings suggested that the MPOA of hypothalamus may be a direct target of androgen and estrogen. Androgen may play important regulatory roles through its receptor and/or the aromatized estrogen in the MPOA of hypothalamus of the wild male ground squirrels.</p>

scholarly journals Seasonal expressions of SPAG11A and androgen receptor in the epididymis of the wild ground squirrels (Citellus dauricus Brandt)

2020 ◽  
Vol 64 (2) ◽  
Author(s):  
Wenyang Yu ◽  
Ziwen Zhang ◽  
Pei Liu ◽  
Xiaoying Yang ◽  
Haolin Zhang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Androgen Receptor ◽  
Luteinizing Hormone ◽  
Epithelial Cells ◽  
Breeding Season ◽  
Seasonal Changes ◽  
Follicle Stimulating Hormone ◽  
Ground Squirrels ◽  
Mrna Levels ◽  
Real Time Quantitative Pcr

Sperm-associated antigen 11A (SPAG11A) is expressed exclusively in the epididymis, which can specifically regulate sperm maturation. The aim of this study was to investigate the seasonal expressions of beta-defensin (SPAG11A) and androgen receptor (AR) in the epididymis of the wild ground squirrels (Citellus dauricus Brandt). Morphologically, the results showed that epididymis length and weight in the breeding season were significantly higher than those of the non-breeding season. Histologically, the results revealed that enlarged lumen diameters, thickened epithelial and abundant sperm in the breeding season while reduced lumen diameters and epithelial with no sperm in the non-breeding season. SPAG11A was intensely expressed in cytoplasm and nucleus of epithelial cells in the breeding season, and weaker staining in the non-breeding season. The immunostaining of AR was only presented in nucleus of smooth muscle cells and epithelial cells in the whole epididymis with stronger staining in the breeding season. The results of real-time quantitative PCR also showed that the mRNA levels of SPAG11A and AR in the epididymis during the breeding season were significantly higher than those of the non-breeding season. In addition, the levels of testosterone (T), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the serum were higher during the breeding season. Taken together, these results suggested that SPAG11A might play an important role to regulate seasonal changes in epididymal function of the wild ground squirrels.

Pancreatic triacylglycerol lipase in a hibernating mammal. II. Cold-adapted function and differential expression

2003 ◽  
Vol 16 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Teresa L. Squire ◽  
Mark E. Lowe ◽  
Vernon W. Bauer ◽  
Matthew T. Andrews
Keyword(s):  
Low Temperature ◽  
High Activity ◽  
Ground Squirrel ◽  
Mammalian Cells ◽  
Lipolytic Activity ◽  
Tissue Expression ◽  
Ground Squirrels ◽  
Mrna Levels ◽  
Western Blots ◽  
Triacylglycerol Lipase

Thirteen-lined ground squirrels ( Spermophilus tridecemlineatus) exploit the low-temperature activity of pancreatic triacylglycerol lipase (PTL) during hibernation. Lipolytic activity at body temperatures associated with hibernation was examined using recombinant ground squirrel and human PTLs expressed in yeast. Both the human and ground squirrel enzymes displayed high activity at temperatures as low as 0°C and showed Q10 values of 1.2–1.5 over a range of 37–7°C. These studies indicate that low-temperature lipolysis is a general property of PTL and does not require protein modifications unique to mammalian cells and/or the hibernating state. Western blots show elevated levels of PTL protein during hibernation in both heart and white adipose tissue (WAT). Significant increases in PTL gene expression are seen in heart, WAT, and testes; but not in pancreas, where PTL mRNA levels are highest. Upregulation of PTL in testes is also accompanied by expression of the PTL-specific cofactor, colipase. The multi-tissue expression of PTL during hibernation supports its role as a key enzyme that shows high activity at low temperatures.

Growth and its relationship to the initial annual cycle of the golden-mantled ground squirrel, Spermophilus lateralis

1981 ◽  
Vol 59 (6) ◽  
pp. 865-871 ◽  
Author(s):  
John A. Phillips
Keyword(s):  
Litter Size ◽  
Annual Cycle ◽  
Ground Squirrel ◽  
Growth And Development ◽  
Reproductive Effort ◽  
Ground Squirrels ◽  
Active Season ◽  
Spermophilus Lateralis ◽  
Significant Difference ◽  
Two Populations

Thirty-eight litters of golden-mantled ground squirrels (Spermophilus lateralis), from two populations that experienced different lengths of active season, were born and raised in the laboratory. Growth and development in young were inversely related to litter size. Offspring from smaller litters were both able to attain their prehibernation peak of body mass sooner and hibernate after fewer days of homeothermy than squirrels from larger litters. Young that remained homeothermic throughout the initial overwintering period were always from large litters and among the slowest growing littermates. Fecundity was lower in females from the temporally compressed environment. There was no significant difference between populations in the nutrition provided by mothers to their litters. The results suggest that reproductive effort is more conservative in populations of ground squirrels that experience short seasons of activity, yet this conservatism allows the offspring of those populations to reach independence and attain the prehibernation state of preparedness at an earlier age than their counterparts from populations of more moderate climates.

scholarly journals Seasonal expressions of androgen receptor, estrogen receptors and cytochrome P450 aromatase in the uteri of the wild Daurian ground squirrels (Spermophilus dauricus)

2018 ◽  
Author(s):  
Yu Wang ◽  
Ziyi Wang ◽  
Wenyang Yu ◽  
Xia Sheng ◽  
Haolin Zhang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Androgen Receptor ◽  
Breeding Season ◽  
Stromal Cells ◽  
Seasonal Changes ◽  
Ground Squirrels ◽  
Sex Steroid ◽  
Expression Levels ◽  
Cytochrome P450 Aromatase ◽  
Glandular Cells

The reproductive tissues including the uterus undergo dramatic changes in seasonal breeders from the breeding to non-breeding seasons. Classically, sex steroid hormones play important roles in the uterine morphology and functions. To clarify the relationship between sex steroid hormones and seasonal changes in the uterine morphology and functions, the wild Daurian ground squirrels (Spermophilus dauricus) were used as seasonal breeder model. And the immunolocalizations and expression levels of androgen receptor (AR), estrogen receptors α and β (ERα and ERβ) and cytochrome P450 aromatase (P450arom) were investigated in the uteri of the wild Daurian ground squirrels in the breeding (April) and the non-breeding (June) seasons via immunohistochemistry, Western blot and RT-PCR. Histologically, the uterine weight, the thickness of endometrium and the glandular density were significantly higher in the uteri of the breeding season than those of the non-breeding season. In both seasons, the immunostaining of AR was only presented in stromal cells of the uteri; the positive staining of ERα and ERβ were localized in stromal cells and glandular cells; P450arom was merely immunolocalized in glandular cells. The protein and mRNA expression levels of ERα, ERβ and P450arom were higher in the uteri of the breeding season than those of the non-breeding season; conversely, the expressions of AR were higher in the uteri of the non-breeding season comparing with those of the breeding season in both protein and mRNA levels. The AR: ER ratio in the uteri of the non-breeding season exceeded the AR: ER ratio in the uteri of the breeding season in the wild Daurian ground squirrels. These results suggested that seasonal changes in the expression levels of AR, ERs and P450arom might be correlated with the uterine morphology and histology changes, and estrogen may play an important autocrine/paracrine role in regulating the uterine functions of the wild Daurian ground squirrels.

Sex differences in estrogenic regulation of preproenkephalin mRNA levels in the medial preoptic area of prepubertal rats

1998 ◽  
Vol 60 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Annabell C. Segarra ◽  
Alex M. Acosta ◽  
Jorge L. González ◽  
Jesús A. Angulo ◽  
Bruce S. McEwen
Keyword(s):  
Sex Differences ◽  
Preoptic Area ◽  
Medial Preoptic Area ◽  
Mrna Levels ◽  
Prepubertal Rats ◽  
Estrogenic Regulation

scholarly journals The Volume of a Sexually Dimorphic Nucleus in the Ovine Medial Preoptic Area/Anterior Hypothalamus Varies with Sexual Partner Preference

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 478-483 ◽  
Author(s):  
Charles E. Roselli ◽  
Kay Larkin ◽  
John A. Resko ◽  
John N. Stellflug ◽  
Fred Stormshak
Keyword(s):  
Sexual Partner ◽  
Preoptic Area ◽  
Medial Preoptic Area ◽  
Anterior Hypothalamus ◽  
Cell Group ◽  
Sexually Dimorphic ◽  
Mrna Levels ◽  
Sexual Preferences ◽  
Estrogen Synthesis ◽  
Sexually Dimorphic Nucleus

Abstract Sheep are one of the few animal models in which natural variations in male sexual preferences have been studied experimentally. Approximately 8% of rams exhibit sexual preferences for male partners (male-oriented rams) in contrast to most rams, which prefer female partners (female-oriented rams). We identified a cell group within the medial preoptic area/anterior hypothalamus of age-matched adult sheep that was significantly larger in adult rams than in ewes. This cell group was labeled the ovine sexually dimorphic nucleus (oSDN). In addition to a sex difference, we found that the volume of the oSDN was two times greater in female-oriented rams than in male-oriented rams. The dense cluster of neurons that comprise the oSDN express cytochrome P450 aromatase. Aromatase mRNA levels in the oSDN were significantly greater in female-oriented rams than in ewes, whereas male-oriented rams exhibited intermediate levels of expression. Because the medial preoptic area/anterior hypothalamus is known to control the expression of male sexual behaviors, these results suggest that naturally occurring variations in sexual partner preferences may be related to differences in brain anatomy and capacity for estrogen synthesis.

Cardiac mechanical restitution in active and hibernating Richardson's ground squirrel

1991 ◽  
Vol 260 (2) ◽  
pp. R353-R358 ◽  
Author(s):  
Z. Q. Zhou ◽  
B. Liu ◽  
W. F. Dryden ◽  
L. C. Wang
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Ground Squirrel ◽  
Inhibitory Effect ◽  
Pause Duration ◽  
Ground Squirrels ◽  
Papillary Muscles ◽  
Contraction Coupling ◽  
Mechanical Restitution ◽  
Significant Difference ◽  
Ca2 Channels

The cardiac mechanical restitution was compared in papillary muscles between the active and the hibernating Richardson's ground squirrels at 0.1, 2.8, and 5 mM external Ca2+ concentration [( Ca2+]o). The amplitude of the restitution was significantly higher in hibernating animals between 37 and 7 degrees C at all [Ca2+]o. The first postrest contraction (F1) was highest at 20 degrees C and lower at 37 and 7 degrees C in both groups. The pause duration for maximum F1 was 30 s in active but 10 s in hibernating animals at 37 degrees C and increased to 100 s in both groups at 7 degrees C. The postrest potentiation was eliminated by 10(-6) M ryanodine at 20 degrees C in both groups, and this inhibitory effect was more pronounced in the hibernating group. Together, our results suggest that the activator Ca2+ for excitation-contraction coupling is mainly derived from the sarcoplasmic reticulum (SR) pool in both active and hibernating ground squirrel, and the dependence on SR Ca2+ release via ryanodine-sensitive Ca2+ channels is more marked in the hibernating state. Furthermore, there is no significant difference in sensitivity of the cardiac mechanical restitution to [Ca2+]o between the active and the hibernating condition.

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