scholarly journals Follicular development in European ground squirrels (Spermophilus citellus) in different phases of the annual cycle

Reproduction ◽  
2008 ◽  
Vol 136 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Eva Millesi ◽  
Anna Strauss ◽  
Tamara Burger ◽  
Ilse E Hoffmann ◽  
Manfred Walzl
Keyword(s):  
Annual Cycle ◽  
Natural Habitat ◽  
Follicular Development ◽  
Ground Squirrels ◽  
Corpora Lutea ◽  
Oestrus Cycle ◽  
Fat Reserves ◽  
Spermophilus Citellus ◽  
Seasonally Breeding ◽  
Plasma Oestradiol

In seasonally breeding mammals, in particular hibernators, reproduction underlies severe energetic and temporal constraints to enable the allocation of sufficient body fat reserves before winter. Thus, the timing of conception in spring can be crucial in terms of reproductive success. This study investigates follicular development in European ground squirrels (Spermophilus citellus) in three phases of the annual cycle: at vernal emergence, after weaning the offspring and shortly before hibernation. The animals were kept in outdoor enclosures within the natural habitat of the species. They were captured in weekly intervals, weighed and reproductive status was determined. Unilateral ovariectomy was scheduled such that the three periods were sampled. Numbers and diameters of tertiary follicles (TF) and corpora lutea (CL) in each ovary were determined, and plasma oestradiol and progesterone levels were analysed. The highest numbers of TF, including Graafian follicles, were found in ovaries at vernal emergence. During post-lactation, the number of TF was lower and active CL appeared in the investigated ovaries. Shortly before hibernation, active CL were present, but luteolysis had started in some individuals. Both oestradiol and progesterone secretion peaked after the termination of lactation and decreased before hibernation. The results demonstrate a second oestrus cycle in European ground squirrels after weaning, including an active luteal phase. This non-reproductive oestrus cycle with its endocrine output is an intriguing phenomenon. It may positively affect both prehibernatory fattening and reproduction in the subsequent season.

scholarly journals Sex and Age Differences in Mass, Morphology, and Annual Cycle in European Ground Squirrels, Spermophilus citellus

1999 ◽  
Vol 80 (1) ◽  
pp. 218-231 ◽  
Author(s):  
E. Millesi ◽  
A. M. Strijkstra ◽  
I. E. Hoffmann ◽  
J. P. Dittami ◽  
S. Daan
Keyword(s):  
Age Differences ◽  
Annual Cycle ◽  
Ground Squirrels ◽  
Spermophilus Citellus ◽  
Sex And Age Differences

Effect of Exposure to Mixture of Heavy Metals Arsenic, Cadmium and Lead on Reproductive Function and Oxidative Stress in Female Rats

2017 ◽  
Vol 9 (03) ◽  
Author(s):  
Choudhuri D. ◽  
Bhattacharjee T.
Keyword(s):  
Oxidative Stress ◽  
Heavy Metals ◽  
Ascorbic Acid ◽  
Reproductive Function ◽  
Reproductive Organs ◽  
Female Rats ◽  
Corpora Lutea ◽  
Oestrus Cycle ◽  
Implantation Sites ◽  
Live Fetus

Background : Toxicological consequences arising from exposure to mixtures of heavy metals especially at low, chronic and environmentally relevant doses are poorly recognised. In the present study, we evaluated effects of chronic exposure to combinations of three metals arsenic (As), cadmium (Cd) and lead (Pb) present frequently in drinking water on reproductive function and oxidative damage caused to reproductive organs of female rats. Method : Female rats were exposed to mixture of metals (As, Cdand Pb) for 90 consecutive days. The gain in body weight and weight of reproductive organs were recorded following autopsy on 91 stday. The oestrus cycle were monitored during entire treatment period. Numbers of corpora lutea, implantation sites, live fetus and survival of the fetus were evaluated in rats mated successfully with untreated male after completion of their respective treatment. Ovarian cholesterol, protein, ascorbic acid and enzyme Δ 5 -3β HSD levels were estimated. Serum levels of steroid hormones oestrogen and progesterone were estimated. Histopathological picture of both ovary and uterus were assessed. Levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidise (GPX) activity, amount of reduced glutathione (GSH) and malondyaldehyde (MDA) in blood, ovary and uterus were measured as biomarkers of oxidative stress. Results : The treated rats showed reduced body weight gain and reduction in the weight of ovary and uterus. Oestrus cycle was disrupted with continuous diestrous in treated animals. Number of corpora lutea, implantation sites and live fetus and the survival of fetus evaluate were reduced significantly in treated groups. The levels of ovarian cholesterol and ascorbic acid increased in treated rats with decrease Δ5 -3β HSD level. There was reduction in serum level of both the ovarian steroid hormones oestrogen and progesterone. The protein levels did not differ between the groups. There was a significant increase in levels of MDA and decrease in levels of all the antioxidant enzymes in treated group. Conclusion : The results revealed there was disruption to reproductive functions with decrease in stereoidogenic activity and associated oxidative stress in female rats treated with combination of mixture of metals (Cd, As and Pb) at low dose for 90 consecutive days.

The Annual Cycle of Wyoming Ground Squirrels in Colorado

1988 ◽  
Vol 69 (4) ◽  
pp. 678-687 ◽  
Author(s):  
K. A. Fagerstone
Keyword(s):  
Annual Cycle ◽  
Ground Squirrels

Follicular Development and Hibernation in European Ground Squirrels

2000 ◽  
pp. 285-292 ◽  
Author(s):  
Eva Millesi ◽  
Susanne Huber ◽  
Manfred Walzl ◽  
John P. Dittami
Keyword(s):  
Follicular Development ◽  
Ground Squirrels

Development in calves and heifers after hypophysial stalk transection or hypophysectomy.

1977 ◽  
Vol 232 (5) ◽  
pp. E497
Author(s):  
L L Anderson
Keyword(s):  
Epithelial Cells ◽  
Sexual Development ◽  
Follicular Development ◽  
Seminal Vesicles ◽  
Corpora Lutea ◽  
Gonadal Function ◽  
Ovarian Weight ◽  
Thyroid Glands ◽  
Estrous Behavior ◽  
Sexually Mature

Growth was inhibited markedly in prepuberal bull and heifer calves after either hypophysial stalk transection or hypophysectomy as compared with that found in sham-operated calves or in unoperated calves. Male mounting behavior and evidence of puberal estrous behavior were lost or undetected after hypophysial stalk transection or hypophysectomy. Testes regressed, contained few spermatogonia and interstitial cells, and lacked spermatogenesis. Epithelial cells of seminal vesicles, bulbourethral glands, and prostate were cuboidal, indicating inadequate testicular androgen. Atresia of numerous ovarian follicles and reduced ovarian weight occurred in hypophysectomized heifer calves. Graafian follicles regressed after hypophysial stalk transection of sexually mature heifers, but ovaries responded to pregnant mare serum and human chorionic gonadotropin by follicular development, ovulation, and formation of multiple corpora lutea. Thyroid and adrenal gland weights decreased and adrenal cortices atrophied after hypophysectomy, but not after stalk transection. Thyroid glands contained colloid-filled follicles with flattened epithelial cells; atrophy was more extensive after hypophysectomy. Hypophysial stalk transection or hypophysectomy severely depresses growth and arrests sexual development in young calves, but in mature animals exongenous gonadotropins can sustain gonadal function.

Nutrient reserve dynamics of lesser snow geese staging at James Bay, Ontario

1979 ◽  
Vol 57 (1) ◽  
pp. 213-219 ◽  
Author(s):  
Ronald C. P. Wypkema ◽  
C. Davison Ankney
Keyword(s):  
Body Weight ◽  
Follicular Development ◽  
James Bay ◽  
Fat Reserves ◽  
Adult Females ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Nutrient Reserve ◽  
Breeding Grounds ◽  
Juvenile Males

We compared mean body weights, nutrient reserves (fat and protein), and an index of feeding of lesser snow geese arriving at and leaving southern James Bay in spring and fall 1976. Feeding increased in spring and decreased in fall. Body weight and protein of adults increased in spring, and fat reserves were maintained. The protein increase of adult females was equivalent to the protein in one egg. Ovarian follicular development in adult females appeared to proceed as reserves became available. Juvenile males had completed body growth by the end of the fall staging period but juvenile females had not. Fat and protein reserves of adults arriving on James Bay in the fall were significantly larger than those of adults after wing molt on the breeding grounds. Fat reserves of adults and juveniles increased significantly during the fall; body weight of juvenile females increased also. The fat gain greatly increases the theoretical maximum flight range of the geese and we suggest it is an important determinant of normal fall migration.

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.

scholarly journals Secretion of inhibin A, inhibin B and inhibin pro-alphaC during the oestrous cycle of the golden hamster (Mesocricetus auratus)

1999 ◽  
Vol 162 (3) ◽  
pp. 451-456 ◽  
Author(s):  
K Ohshima ◽  
H Kishi ◽  
M Itoh ◽  
G Watanabe ◽  
K Arai ◽  
...  
Keyword(s):  
Golden Hamster ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Early Morning ◽  
Oestrous Cycle ◽  
Inhibin B ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inhibin A ◽  
Negative Relationships ◽  
Plasma Oestradiol

Plasma concentrations of inhibin pro-alphaC, inhibin A and inhibin B were determined by enzyme-linked immunosorbent assay at 6 h intervals throughout the 4-day oestrous cycle of the golden hamster. Plasma concentrations of follicle-stimulating hormone (FSH) and oestradiol-17beta were also measured by radioimmunoassay during the oestrous cycle. Plasma concentrations of inhibin A increased from the early morning of day 1 (day 1=day of ovulation) and reached plateau levels at 0500 h on day 2. An abrupt increase in plasma concentrations of inhibin A was found at 1700 h on day 4, when the preovulatory FSH surge was observed. An increase in plasma concentrations of inhibin B occurred on day 1 and reached plateau levels at 1700 h on day 1. The levels remained elevated until 0500 h on day 4 and declined gradually by 2300 h on day 4. Plasma concentrations of inhibin pro-alphaC gradually increased with some fluctuation from day 1 to 1700 h on day 4 and then declined. Significant negative relationships were noted between plasma FSH and both dimeric forms of inhibin from day 1 to day 3. Significant positive relationships were found between plasma oestradiol-17beta and inhibin A or inhibin pro-alphaC throughout the oestrous cycle. In contrast, no significant relationship was found between plasma oestradiol-17beta and inhibin B. These findings suggest that both dimeric forms of inhibin play a role in the regulation of FSH secretion during follicular development. These findings also suggest that inhibin pro-alphaC could be secreted primarily by large follicles, and early atretic follicles could also be responsible for inhibin pro-alphaC secretion. On the other hand, the secretory pattern of dimeric inhibins might shift from inhibin B to inhibin A with follicular development.

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