scholarly journals Gender differences in the inhibitory effects of a reduction in ambient temperature and a reduction in food quantity on reproduction in the Southern African rodent, Rhabdomys pumilio

Reproduction ◽  
2001 ◽  
pp. 385-395 ◽  
Author(s):  
C Jackson ◽  
RT Bernard
Keyword(s):  
Ambient Temperature ◽  
Reproductive Organs ◽  
Inhibitory Effect ◽  
Uterine Wall ◽  
Corpora Lutea ◽  
Eastern Cape ◽  
Rhabdomys Pumilio ◽  
Food Quantity ◽  
Two Factors ◽  
The Masses

The effects of a reduction in ambient temperature (from 26 degrees C to 15 degrees C) and a 10% reduction in daily food consumption on reproductively active male and female four-striped field mice ( Rhabdomys pumilio) were investigated. In male R. pumilio, both reduced ambient temperature and a reduction in food quantity had an inhibitory effect on spermatogenesis and on size of the reproductive organs, and this was greatest when the two factors were combined and the effect of fat was removed. Female R. pumilio responded differently and reproduction was inhibited by a reduction in food quantity, irrespective of ambient temperature. The masses of the ovaries and uterus, the numbers of developing follicles and corpora lutea, and the development of the uterine wall were all reduced by food deprivation at 26 degrees C to levels similar to those that resulted from a reduction in ambient temperature to 15 degrees C with a reduction in food quantity. It is concluded that reproduction in R. pumilio from the Eastern Cape Province of South Africa is opportunistic, that reproduction will be inhibited by an energetic challenge and that there is sexual dimorphism in the response to ambient temperature and food supply.

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.

scholarly journals On the occurrence of the œstrous cycle after X-ray sterilisation.—Part I. Irradiation of mice at three weeks old

1926 ◽  
Vol 100 (702) ◽  
pp. 172-199 ◽  
Keyword(s):  
Reproductive Organs ◽  
Inhibitory Effect ◽  
Ovarian Cycle ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
X Ray ◽  
Periodic Growth ◽  
Main Series ◽  
To Receive ◽  
Female Reproductive Organs

The cyclic activities of the female reproductive organs of mammals, constituting the œstrous cycle, fall naturally into two main series, i. e ., the uterine cycle and the ovarian cycle, and the correlation between these two forms one of the most intricate problems of internal secretion. Two chief problems are presented—( a ) what stimuli produce the uterine cycle in the first place, and ( b ) how is the uterine cycle so synchronised with the ovarian cycle as to result in the uterus being ready to receive the fertilised ovum just after the time of ovulation? Since ovariotomy results in cessation of the cycle, whereas excision of the other reproductive organs has not this effect, it is necessary to suppose that the controlling power resides in the ovary, and further, since transplantation of the ovary does not result in the cessation of the cycle, that the means of control is hormonic. The alternating maturation of follicles and corpora lutea in the ovaries is exactly synchronised with the changes which take place in the uterus, and it is therefore reasonable to look to the periodic growth of one or other of these ovarian structures for the origin of the periodic hypertrophy of the uterus. Owing to the fact, however, that in many mammals œstrus sets in when no corpora lutea are present in the ovary, these structures can be eliminated as originators of the œstrous cycle. Similarly, the supposition that the corpus Corpus luteum has an inhibitory effect, the removal of which allows œstrus to appear, can only be applied to certain special conditions. If, therefore, any cyclic structure of the ovary is responsible for the regulation of the œstrous cycle, it must be the maturing follicle. This conclusion is supported by the following facts:— ( a ) Œstrus first appears when ovulation starts at puberty, and the œstrous cycle stops when ovulation ceases at the menopause.

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.

PSVII-3 Evaluation of dietary OmniGen AF supplementation and PG600 injection on reproductive characteristics of gilts

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 411-411
Author(s):  
Jun Chen ◽  
Jung Wook Lee ◽  
Jim J Monegue ◽  
Richard Niblett ◽  
Kim Williams ◽  
...  
Keyword(s):  
Animal Health ◽  
Basal Diet ◽  
Corpora Lutea ◽  
Crown Rump Length ◽  
Reproductive Characteristics ◽  
Ovary Weight ◽  
Diet Formulation ◽  
Two Factors ◽  
Diet Control ◽  
Dietary Treatments

Abstract A cooperative study evaluated effects of supplemental dietary OmniGen AF (OG; Phibro Animal Health Corporation) on reproductive characteristics of gilts. Crossbred gilts (n = 56; initial body weight = 152.3 ± 9.7 kg) were assigned to treatments in a 2 x 2 factorial design [diet (OG or control) and PG600 (Merck Animal Health, El Dora, KS) injection (Yes or No)]. Dietary treatments were: 1) corn-SBM basal diet (control) that met NRC (2012) requirement estimates, or 2) control plus 0.75% OG and were fed 35 to 40 d prior to breeding. A common diet formulation was used by both stations. Gilts were estrous-synchronized by 14-d feeding of Matrix (Merck Animal Health). PG600 injections occurred 24 hours after Matrix withdrawal. Gilts were weighed at breeding and preslaughter (at d 39 to 48 postbreeding) and were euthanized to evaluate reproductive characteristics. There were no OG x PG600 interactions on any response measures (P > 0.15). Mean responses did not differ (P > 0.20) when gilts were fed control or OG diets, respectively, for total uterus weight (6,065 vs. 5,883 g), uterine horn length (129.2 vs. 123.9 cm), ovary weight (9.66 vs. 9.94 g), total corpora lutea (CL) number (25.0 vs. 25.3), individual CL weight (0.41 vs. 0.43 g), total follicular fluid weight (3.17 vs. 3.03 g), individual placenta weight (86.3 vs. 86.4 g), total fetuses (14.2 vs. 13.0), and fetus crown-rump length (7.97 vs. 7.66 cm). Supplementation with OG reduced (P = 0.04) individual placenta fluid volume of gilts (150.6 vs. 115.4 mL). PG600 injection increased (P < 0.001) ovary weight (9.03 vs. 10.57 g), total CL (18.09 vs 32.27) and reduced CL weight (0.46 vs. 0.38 g). The results demonstrated classic PG600 responses on reproductive characteristics but no effects of 0.75% OG supplementation nor an interaction between the two factors.

Inhibitory Effects of Indomethacin on Implantation and its Related Phenomena

1996 ◽  
Vol 24 (4) ◽  
pp. 358-362 ◽  
Author(s):  
K Kanayama ◽  
H Osada ◽  
K Nariai ◽  
T Endo
Keyword(s):  
Birth Rate ◽  
Inhibitory Effect ◽  
High Rate ◽  
Control Group ◽  
Corpora Lutea ◽  
Response Relationship ◽  
Inhibitory Effects ◽  
Dose Response Relationship ◽  
Dose Dependent ◽  
Implantation Period

The dose-response relationship for the inhibitory effect of indomethacin on implantation and continuance of pregnancy was examined in four groups of rabbits administered with indomethacin (2.5, 5.0, 7.5 and 10.0 mg/kg) during the implantation period and compared with a control group. Implanted fetuses and corpora lutea were counted by laparotomy, and the number of offspring born was noted. The inhibitory effect of indomethacin on implantation was found to be dose–dependent, and the birth rate decreased in the indomethacin groups compared with the control group. As a result, even where implantation had been achieved, death of the implanted fetuses occurred at a high rate in rabbits administered with indomethacin during the implantation period.

Inhibitory Effect of Tributyltin on Expression of Steroidogenic Enzymes in Mouse Testis

2008 ◽  
Vol 27 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Suel-Kee Kim ◽  
Jong-Hoon Kim ◽  
Jung Ho Han ◽  
Yong-Dal Yoon
Keyword(s):  
Germ Cells ◽  
Leydig Cells ◽  
Serum Testosterone ◽  
Hydroxysteroid Dehydrogenase ◽  
Reproductive Organs ◽  
Inhibitory Effect ◽  
Testicular Development ◽  
Steroidogenic Enzymes ◽  
Hormone Production ◽  
Induced Apoptosis

Tributyltin (TBT) is known to disrupt the development of reproductive organs, thereby reducing fertility. The aim of this study was to evaluate the acute toxicity of TBT on the testicular development and steroid hormone production. Immature (3-week-old) male mice were given a single administration of 25, 50, or 100 mg/kg of TBT by oral gavage. Lumen formation in seminiferous tubule was remarkably delayed, and the number of apoptotic germ cells found inside the tubules was increased in the TBT-exposed animals, whereas no apoptotic signal was observed in interstitial Leydig cells. Reduced serum testosterone concentration and down-regulated expressions of the mRNAs for cholesterol side-chain cleavage enzyme (P450scc), 17α-hydroxylase/C17–20 lyase (P45017α), 3β-hydroxysteroid-dehydrogenase (3β-HSD), and 17β-hydroxysteroid-dehydrogenase (17β-HSD) were also observed after TBT exposure. Altogether, these findings demonstrate that exposure to TBT is associated with induced apoptosis of testicular germ cells and inhibition of steroidogenesis by reduction in the expression of steroidogenic enzymes in interstitial Leydig cells. These adverse effects of TBT would cause serious defects in testicular development and function.

scholarly journals Endogenous flow-induced nitric oxide reduces superoxide-stimulated Na/H exchange activity via PKG in thick ascending limbs

2015 ◽  
Vol 308 (5) ◽  
pp. F444-F449 ◽  
Author(s):  
Nancy J. Hong ◽  
Jeffrey L. Garvin
Keyword(s):  
Nitric Oxide ◽  
Soluble Guanylate Cyclase ◽  
Inhibitory Effect ◽  
Dependent Protein Kinase ◽  
Two Factors ◽  
Endogenous Nitric Oxide ◽  
Dependent Protein ◽  
Acid Load ◽  
Luminal Flow ◽  
Ly 83583

Luminal flow stimulates endogenous nitric oxide (NO) and superoxide (O2−) production by renal thick ascending limbs (TALs). The delicate balance between these two factors regulates Na transport in TALs; NO enhances natriuresis, whereas O2− augments Na absorption. Endogenous, flow-stimulated O2− enhances Na/H exchange (NHE). Flow-stimulated NO reduces flow-induced O2−, a process mediated by cGMP-dependent protein kinase (PKG). However, whether flow-stimulated, endogenously-produced NO diminishes O2−-stimulated NHE activity and the signaling pathway involved are unknown. We hypothesized that flow-induced NO reduces the stimulation of NHE activity caused by flow-induced O2− via PKG in TALs. Intracellular pH recovery after an acid load was measured as an indicator of NHE activity in isolated, perfused rat TALs. l-Arginine, the NO synthase substrate, decreased NHE activity by 34 ± 5% ( n = 5; P < 0.04). The O2− scavenger tempol decreased NHE activity by 46 ± 8% ( n = 6; P < 0.004) in the absence of NO. In the presence of l-arginine, the inhibitory effect of tempol on NHE activity was reduced to −19 ± 6% ( n = 6; P < 0.03). The soluble guanylate cyclase inhibitor LY-83583 blocked the effect of l-arginine thus restoring tempol's effect on NHE activity to −42 ± 4% ( n = 6; P < 0.0005). The PKG inhibitor KT-5823 also inhibited l-arginine's effect on tempol-reduced NHE activity (−43 ± 5%; n = 5; P < 0.03). We conclude that flow-induced NO reduces the stimulatory effect of endogenous, flow-induced O2− on NHE activity in TALs via an increase in cGMP and PKG activation.

scholarly journals Basal blood glucose concentration in free-living striped mice is influenced by food availability, ambient temperature and social tactic

2015 ◽  
Vol 11 (5) ◽  
pp. 20150208 ◽  
Author(s):  
Carsten Schradin ◽  
Neville Pillay ◽  
Anna Kondratyeva ◽  
Chi-Hang Yuen ◽  
Ivana Schoepf ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Ambient Temperature ◽  
Food Availability ◽  
Glucose Concentration ◽  
Extended Family ◽  
Blood Glucose Concentration ◽  
Energy Regulation ◽  
Free Living ◽  
Blood Samples ◽  
Rhabdomys Pumilio

Vertebrates obtain most of their energy through food, which they store mainly as body fat or glycogen, with glucose being the main energy source circulating in the blood. Basal blood glucose concentration (bBGC) is expected to remain in a narrow homeostatic range. We studied the extent to which bBGC in free-living African striped mice ( Rhabdomys pumilio ) is influenced by ecological factors with a bearing on energy regulation, i.e. food availability, abiotic environmental variation and social tactic. Striped mice typically form extended family groups that huddle together at night, reducing energetic costs of thermoregulation, but solitary individuals also occur in the population. We analysed 2827 blood samples from 1008 individuals of seven different social categories that experienced considerable variation in food supply and abiotic condition. Blood samples were taken from mice in the morning after the overnight fast and before foraging. bBGC increased significantly with food plant abundance and decreased significantly with minimum daily ambient temperature. Solitary striped mice had significantly higher bBGC than group-living striped mice. Our results suggest that adaptive responses of bBGC occur and we found large natural variation, indicating that bBGC spans a far greater homeostatic range than previously thought.

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