PROGESTERONE AND 20α-HYDROXYSTEROID-DEHYDROGENASE REGULATION IN THE CORPUS LUTEUM OF THE PREGNANT RAT

1979 ◽  
Vol 90 (1) ◽  
pp. 176-184 ◽  
Author(s):  
K. Loewit ◽  
N. Zambelis
Keyword(s):  
Wistar Rats ◽  
Time Course ◽  
Hydroxysteroid Dehydrogenase ◽  
Mechanisms Of Action ◽  
Corpora Lutea ◽  
Pregnant Rat ◽  
Female Wistar Rats ◽  
Series Of Experiments ◽  
Complex Regulation

ABSTRACT Female Wistar rats were mated and passively immunized against bovine luteinizing hormone (bLH) between days 7–12 of gestation. In a first series of experiments the effect of simultaneous progesterone treatment on the histochemically detectable activity of 20α-hydroxysteroiddehydrogenase (20α-OHSD) in the corpora lutea of pregnancy was evaluated. In other experiments the exact time course was established between the first histologically demonstrable signs of termination of pregnancy and the appearance of 20α-OHSD activity in corpora lutea of pregnancy. It was found that progesterone substitution not only prevented the deleterious effects of the anti-bLH-serum on gestation but also the re-appearance of 20α-OHSD activity in the corpora lutea of pregnancy up to day 12 of pregnancy. Moreover in animals injected with anti-bLH-serum from day 7 on and sacrificed on days 8–2, signs of foetal destruction clearly preceded the pathological re-appearance of 20α-OHSD activity by 2–3 days. These results support previous findings on a direct or indirect role of progesterone in the complex regulation of 20α-OHSD activity. Possible mechanisms of action are discussed.

ZUR BEDEUTUNG DES HYPOPHYSÄREN LUTEINISIERUNGSHORMONS FÜR SCHWANGERSCHAFT, GEBURT UND LACTATION BEI DER RATTE

1970 ◽  
Vol 65 (3_Suppl) ◽  
pp. S5-S32 ◽  
Author(s):  
K. Loewit
Keyword(s):  
Luteinizing Hormone ◽  
Early Pregnancy ◽  
Hydroxysteroid Dehydrogenase ◽  
The State ◽  
Termination Of Pregnancy ◽  
Progesterone Level ◽  
Corpora Lutea ◽  
Regulatory Properties ◽  
Duration Of Pregnancy

ABSTRACT The role of luteinizing hormone (LH) for the maintenance of pregnancy, parturition and lactation was investigated by immunological and histochemical methods in the rat. Neutralisation of endogenous rat-LH with Rabbit-Anti-Bovine-LH-Serum (selective hypophysectomy) from days 7-12 of pregnancy resulted in reabsorption of the foetuses and the reappearance of strong 20α-hydroxysteroid-dehydrogenase (20α-OHSD) activity in the corpora lutea (CL) of pregnancy, which normally show no such activity at that time. This effect could be prevented in part by concurrent pregnenolone administration and fully by progesterone, but was not influenced by oestrogen or prolactin. It is concluded that in early pregnancy LH is the main luteotrophic hormone in the rat even though prolactin might act synergistically with it. Antiserum treatment after the 12th day of gestation had no influence on the state or duration of pregnancy or on parturition. LH-injections during the first half of pregnancy had no luteolytic effects i. e. they did not activate 20α-OHSD activity. After day 16 they advanced the reappearance of the enzyme, but delayed parturition or resulted in stillbirths. Neither LH nor antiserum seemed to alter lactation. Since progesterone prevented both the termination of pregnancy and the recurrence of 20α-OHSD activity, it should have some regulatory properties on the enzyme. It is discussed whether the gonadotrophin-dependent progesterone level could regulate the 20α-OHSD activity rather than result from it.

scholarly journals Regulation of nitric oxide synthase isoforms and role of nitric oxide during prostaglandin F2alpha-induced luteolysis in rabbits

Reproduction ◽  
2003 ◽  
pp. 807-816 ◽  
Author(s):  
C Boiti ◽  
G Guelfi ◽  
D Zampini ◽  
G Brecchia ◽  
A Gobbetti ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Time Course ◽  
Plasma Concentrations ◽  
Physiological Role ◽  
Total Activity ◽  
Corpora Lutea ◽  
Prostaglandin F ◽  
Oxide Synthase

Total activity of nitric oxide synthase (NOS) and the gene expression of both endothelial NOS (eNOS) and inducible NOS (iNOS) isoforms in corpora lutea of pseudopregnant rabbits were examined during prostaglandin F(2alpha) (PGF(2alpha))-induced luteolysis. Corpora lutea were collected at 0, 6, 12, 24 and 48 h after an injection of PGF(2alpha) at day 9 of pseudopregnancy. At 12 h after PGF(2alpha) administration, luteal mRNA encoding eNOS decreased (P0.05) by 40% and remained low throughout the subsequent 36 h, whereas eNOS protein increased (P0.05) two- to threefold. By contrast, expression of mRNA encoding iNOS was poor and remained fairly constant, but transcription increased eightfold (P0.01) within 6 h after PGF(2alpha) treatment and then decreased to values similar to those of controls. Total NOS activity increased twofold (P0.01) at 6 h after treatment and remained high thereafter, whereas progesterone concentrations in explanted corpora lutea decreased (P0.01) from 302.4+/-42.3 pg x mg(-1) at day 9 to 58.6+/-8.3 at 48 h later, and peripheral plasma concentrations of progesterone declined too. Long-term administration of Nomega-nitro-L-arginine methyl ester (0.6 g l(-1) per os) from day 2 of pseudopregnancy onward partially blocked the luteolytic action of PGF(2alpha) administered at day 9 of pseudopregnancy. In nitric oxide (NO)-deficient rabbits, progesterone concentrations remained higher (P0.01) than in controls at 24-48 h after PGF(2alpha) administration (4.5 to 3.2 ng x ml(-1), respectively). These data are the first to characterize NOS activity. The time course of expression of eNOS and iNOS in rabbit corpora lutea during PGF(2alpha)-induced luteolysis gives additional support to a physiological role of NO in the regulation of regression of corpora lutea in rabbits.

scholarly journals Evaluation of protective effect of myricetin, a bioflavonoid in dimethyl benzanthracene-induced breast cancer in female Wistar rats

2014 ◽  
Vol 03 (02) ◽  
pp. 107-111 ◽  
Author(s):  
J. K. Jayakumar ◽  
P. Nirmala ◽  
B.A. Praveen Kumar ◽  
Ashok P. Kumar
Keyword(s):  
Breast Cancer ◽  
Wistar Rats ◽  
Statistical Significance ◽  
Treated Animal ◽  
Group 4 ◽  
Female Wistar Rats ◽  
Group 3 ◽  
Group 2 ◽  
And Control

Abstract Background: Breast cancer is one of the most common cancers worldwide. Alarmingly, the incidence of breast cancer is rising rapidly in India. Aim: The present research was focused to assess the role of myricetin; a bioflavonoid in 7,12-dimethylbenzanthracene (DMBA)-induced breast cancer in female Wistar rats. Materials and Methods: A total of 36 female Wistar rats (total 6 groups, n = 6 per group) 6 - 8 weeks old, weighing 150 gm were used in the study. DMBA was given at the dose of 7.5 mg/kg subcutaneously in the mammary region once a week for 4 consecutive weeks in group 2. Vincristine was given in the dose of 500 μg/kg intraperitonially every week for 4 consecutive weeks in group 3. Myricetin was given orally in a dose of 50, 100, and 200 mg/kg in group 4, 5, and 6 respectively. The statistical significance of the data was determined using one way analysis of variance and Duncan’s multiple range test. Results: The result showed that myricetin increased the antioxidant levels in plasma, erythrocyte lysate, and breast tissue and was effective in preventing the oxidative damage induced by the carcinogen DMBA. Myricetin 50, 100, and 200 mg/kg/oral for 120 days treated animal resulted comparable results to that of standard vincristine and control groups. Conclusions: Myricetin was found to be either equieffective or more effective than vincristine in all the parameters studied. Myricetin proved the capacity of flavonols to act as antioxidant in cells represents a potential treatment in the field of oncology.

scholarly journals Endogenous Ovarian Angiogenesis in Polycystic Ovary Syndrome-Like Rats Induced by Low-Frequency Electro-Acupuncture: The CLARITY Three-Dimensional Approach

2018 ◽  
Vol 19 (11) ◽  
pp. 3500 ◽  
Author(s):  
Tong Ma ◽  
Peng Cui ◽  
Xiaoyu Tong ◽  
Wei Hu ◽  
Linus Shao ◽  
...  
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Polycystic Ovary ◽  
Three Dimensional ◽  
Low Frequency ◽  
Corpora Lutea ◽  
Ovary Syndrome ◽  
Follicular Maturation ◽  
Female Wistar Rats ◽  
Follicle Maturation

We sought to determine the role of ovarian vascularity and neo-angiogenesis in the development of mature follicles in polycystic ovary syndrome (PCOS) and to identify any changes induced by low-frequency electro-acupuncture (EA). Twenty-eight 21-day-old female Wistar rats were randomly divided into four groups—Control, Obesity, PCOS-like, and PCOS-like-EA (n = 7/group). Rats in the Obesity group were fed a high-fat diet throughout the experiment. Rats in the PCOS-like and PCOS-like-EA groups were implanted with a sustained-release tube containing 5α-dihydrotestosterone (DHT) beneath the skin of the neck. Rats in the PCOS-like-EA group received low-frequency EA treatment starting at 70 days for 30 min five times a week for four weeks. At the end of the experiment, all rats were euthanized and perfused with hydrogel. The ovaries were collected for clarification and imaging, and ovarian vascularity and neo-angiogenesis were analyzed. Compared with Control and Obesity rats, the ovaries in DHT-induced PCOS-like rats were smaller in size and had fewer mature follicles and corpora lutea. EA increased angiogenesis in the antral follicles of PCOS-like rats, which in turn promoted follicle maturation, ovulation, and CL formation. Therefore, endogenous ovarian angiogenesis plays a very important role in follicular maturation and might be one of the peripheral and direct mechanisms of EA on PCOS.

Analysis of cathodoluminescence emitted from lipid droplets in corpora lutea of estrus cyclic and pregnant rat by analytical color fluorescence EM

1990 ◽  
Vol 48 (3) ◽  
pp. 768-769
Author(s):  
Gang Ning ◽  
Tohru Nakano ◽  
Toyoshi Fujimoto ◽  
Hirotami Koike ◽  
Kazuo Ogawa
Keyword(s):  
Electron Microscope ◽  
Lipid Droplets ◽  
Flat Surface ◽  
Chemical Components ◽  
Corpora Lutea ◽  
Sodium Pentobarbital ◽  
Chemical Fixation ◽  
Estrus Cycle ◽  
Pregnant Rat ◽  
Female Wistar Rats

We developed an analytical color fluorescence electron microscope (ACFEM), which enabled us to detect strong cathodoluminescence (CL) emitted from lipid droplets (LD) in various cells. In previous studies, we demonstrated that steroids and retinoids are most likely to be the chemical components emitting CL. In the present research, we examined CL in corpora lutea (CpL) of rats at various stages of the estrus cycle and gestation by ACFEM.Adult female Wistar rats either following a normal estrus cycle or pregnant were either decapitated or anesthetized by sodium pentobarbital and the ovary was excised and cut into small pieces. The tissue was attached to aluminium sample tips, rapidly frozen by liquid propane cooled in liquid nitrogen without chemical fixation and cut with a cryo-ultra microtome to make a flat surface for observation. The specimens were kept at -100°C on a cryo-stage and observed by an ACFEM constructed on a basis of a high resolution scanning electron microscope (AKASHI DS-130).

Ovariectomy and its Antioxidative Effect on Bone

2010 ◽  
Author(s):  
Durg V. Rai ◽  
Harcharan Singh Ranu
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Bone Loss ◽  
Wistar Rats ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Female Wistar Rats ◽  
The Impact

Ovarian hormone deficiency increases the generation of reactive oxygen species. Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Cells have a number of defense mechanisms to protect themselves from the toxicity of ROS. There is increasing evidence of the role of free radicals in bone resorption and bone loss. Ovariectomised female wistar rats had been used as the animal model for the study of osteoporosis. Even though, there are studies portraying the role of free radicals in bone loss, the defense mechanism adapted by bone in ovariectomised animals remains obscure. So, the impact of ovariectomy on the bone antioxidant system in rats was investigated. Twenty female wistar rats were taken and divided into two groups: ovariectomised and control. It had been found that a significant (p<0.001) decrease in the activity of various enzymes like CAT (catalase), SOD (superoxide dismutase) (p<0.001), GST (glutathione-s-transferase). However, an increase in the malondialdehyde levels was found to be 30% in the ovariectomised rats as compared to the controls. Thus the study elucidates the oxidative stress in bone under ovariectomy.

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