Effects of arginine vasotocin, oxytocin, and arginine vasopressin on steroid-induced surges of luteinizing hormone and prolactin in ovariectomized rats

1980 ◽  
Vol 94 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Ronald L. Salisbury ◽  
Richard J. Krieg ◽  
Hugo R. Seibel
Keyword(s):  
Luteinizing Hormone ◽  
Arginine Vasotocin ◽  
Ovariectomized Rats ◽  
Sprague Dawley ◽  
Lh Surge ◽  
Ovx Rats ◽  
Sprague Dawley Rats ◽  
Oestradiol Benzoate ◽  
Significant Augmentation ◽  
Low Levels

Abstract. Several studies have indicated that arginine vasotocin (AVT), a nonapeptide closely related to vasopressin (ADH) and oxytocin (OT), may act as a pineal antigonadotrophic factor. The present studies were designed to investigate the effects of AVT on the luteinizing hormone (LH) and prolactin (Prl) release induced by sequential steroid priming of ovariectomized (OVX). rats. Sprague-Dawley rats were used 6–8 weeks post-OVX. After implantation of an intra-atrial bleeding catheter, animals were primed with 5 μg of oestradiol benzoate (EB) at 08.00 h on the next morning. Forty-eight hours later 1.5 mg of progesterone (P) was injected and animals were divided into groups which received either saline, AVT (1 of 4 doses), ADH, or OT. The saline or peptides were infused via the intra-atrial catheter at 10.00, 11.00, 12.00, and 13.00 h. Hourly blood sampling was performed at 11.00–18.00 h, and at 21.00 h. The 11.00, 12.00, and 13.00 h samples were taken 10 min after saline or peptide infusion. LH and Prl responses to the peptide infusions could be divided into pre-surge and surge effects. AVT caused a slight, but significant elevation of the normally low levels of LH and Prl which occurred before the onset of their surges. Only the highest dose of AVT (1.0 μg) blocked the LH surge. ADH, however, was capable of stimulating LH and Prl release during the pre-surge period and of inhibiting the LH surge. AVT at a dose of 0.5 or 1.0 μg specifically blocked the onset of the Prl surge, causing Prl to drop to its lowest level at 14.00 h - the time at which Prl levels were maximal in saline-treated animals. After this initial inhibition, however, Prl levels rebounded to show a delayed surge. OT infusion, on the other hand, caused a significant augmentation of the Prl surge. These data indicate that AVT may specifically block the onset of the Prl surge seen after sequential steroid priming of OVX rats, while OT may facilitate the Prl surge.

scholarly journals Effect of Resistance Training on NADPH Oxidase and Adiponectin in PVAT of OVX Rats

2021 ◽  
Vol 30 (2) ◽  
pp. 205-212
Author(s):  
Erling Guo ◽  
Jin-Hwan Yoon ◽  
Wooyeon Jo ◽  
Jaeho Jin ◽  
Sang Ki Lee
Keyword(s):  
Adipose Tissue ◽  
Resistance Training ◽  
Nadph Oxidase ◽  
Abdominal Aorta ◽  
Sham Group ◽  
Ovariectomized Rats ◽  
Sprague Dawley ◽  
Perivascular Adipose Tissue ◽  
Ovx Rats ◽  
Sprague Dawley Rats

PURPOSE: Perivascular adipose tissue (PVAT) is a type of adipose tissue that surrounds vessels to provide anti-contractile effects. This study aimed to investigate the effect of resistance training on NADPH oxidase, adiponectin, and endothelial NOS (eNOS) expression in the abdominal aorta and PVAT of ovariectomized rats.METHODS: Sprague-Dawley rats at 20 weeks of age were divided into three groups: sham control (Sham, n=10), OVX-control (OVX_ Con, n=10), and OVX-resistance exercise (OVX_Rex, n=10). Resistance training was performed by climbing a ladder for 12 weeks. Western blotting was used to analyze target protein expression in the rat abdominal aorta and PVAT.RESULTS: NADPH oxidase (p67phox) expression was significantly higher in the OVX_Con group than in the sham group, but it was significantly decreased in the OVX_Rex group. The expression of adiponectin, AKT, and eNOS in both abdominal aorta and PVAT was significantly reduced in the OVX_Con group than in the Sham group, but it was improved in the OVX_Rex group.CONCLUSIONS:The results suggest that regular resistance training inhibits p67phox and increases adiponectin expression and phosphorylation of AKT and eNOS in abdominal aortic PVAT of ovariectomized rats.

scholarly journals Prolonged feeding of difructose anhydride III increases strength and mineral concentrations of the femur in ovariectomized rats

2005 ◽  
Vol 94 (2) ◽  
pp. 268-274 ◽  
Author(s):  
Rieko Mitamura ◽  
Hiroshi Hara
Keyword(s):  
Bone Strength ◽  
Ovariectomized Rats ◽  
Control Group ◽  
Sprague Dawley ◽  
Mineral Density ◽  
Ovx Rats ◽  
Sprague Dawley Rats ◽  
Promotive Effect ◽  
Mineral Concentrations ◽  
The Relationship

This study demonstrates that feeding difructose anhydride III (DFAIII) improves bone strength and femoral mineral concentrations in a rat model of oestrogen deficiency. We showed the relationship between Ca, Mg and P absorption and bone characteristics in rats. Two groups of female Sprague-Dawley rats (6 weeks old) underwent bilateral ovariectomy (ovariectomized rats, OVX rats) or bilateral laparotomy (sham rats). At 10 weeks old, OVX and sham rats were divided into three subgroups and fed a control, 1·5 % DFAIII or 3 % DFAIII diet for 8 weeks, respectively. Ca but not Mg absorption rates were lowered by ovariectomy; however, ingestion of the 1·5 % and 3 % DFAIII diets similarly restored the reduced Ca absorption in OVX rats at 4 and 8 weeks after feeding of the test diets. DFAIII increased Mg absorption dose-dependently in sham and OVX rats. The bone strength, femoral Ca and Mg concentrations, and distal bone mineral density in the 3 % DFAIII group were higher than those in the control group in OVX rats. The absorption rates of Ca and Mg were significantly correlated with femoral Ca and Mg concentrations and strength, which suggests that increasing both Ca and Mg absorption improves bone characteristics in OVX rats. There were no differences in any of the variables in the femur between the 1·5 % and 3 % DFAIII groups in OVX rats. In conclusion, feeding of a low dose of DFAIII increased intestinal Ca and Mg absorption, and the promotive effect of DFAIII persisted for over 8 weeks. This effect was associated with prevention of ovariectomy-induced osteopenia.

scholarly journals NIFEDIPINEON;

2019 ◽  
Vol 26 (02) ◽  
Author(s):  
Sidra Hamid ◽  
Qaiser Aziz ◽  
Aneela Jamil ◽  
Lubna Meraj ◽  
Shazia Muazam ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Luteinizing Hormone ◽  
Serum Testosterone ◽  
Serum Testosterone Level ◽  
Control Group ◽  
Channel Blockers ◽  
Sprague Dawley ◽  
Study Objective ◽  
Serum Luteinizing Hormone ◽  
Sprague Dawley Rats

Background: The most potent and effective drugs used for the management of blood pressure in hypertensive patients are Calcium channel blockers (CCBs). Nifedipine, a CCB, acts by blocking entry of calcium ions all the way through the voltage gated calcium channels (VGCCs) of L-type present in the smooth muscle cells of blood vesselsand reducing the blood pressure by decreasing the peripheral vascular resistance. Objectives: The study objective was to determine the effect of nifedipine on serum luteinizing hormone (LH) and serum testosterone in male Sprague Dawley rats. Study Design: Animal experimental study. Setting: All experiments were conducted at the Research laboratory of Shifa College of Medicine, Islamabad along with National Institute of Health (NIH), Islamabad. Period: October, 2012 to April, 2014. Methods: The study was done on adult male Sprague-Dawley rats (N= 60) aged 90-120 days old and their body weights varied between 200 + 50 grams. Rats were divided intotwo groups (n=30). Group A was administered0.5 ml distilled water/rat daily orally, group B was administered orally with nifedipine 50 mg/kg/rat dissolved in 1ml of DMSO. All the doses were given to rats for 8 weeks. After 8 weeks, serum luteinizing hormone and serum testosterone were measured in both groups. Results: In Nifedipine treated group, serum testosterone was significantly decreasedand serum LH was unaffected as compared to the control group. Conclusion: Nifedipine has adverse effects on male fertility as it decreases serum testosterone level.

CHANGES IN SERUM LEVELS OF FOLLICLE STIMULATING HORMONE AND LUTEINIZING HORMONE SHORTLY BEFORE AND AFTER PARTURITION IN RATS

1974 ◽  
Vol 75 (3) ◽  
pp. 491-496 ◽  
Author(s):  
Junichi Mori ◽  
Hiroshi Nagasawa ◽  
Reiko Yanai ◽  
Junji Masaki
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Serum Levels ◽  
Sprague Dawley ◽  
Appreciable Change ◽  
Serum Lh ◽  
Sprague Dawley Rats ◽  
Before And After ◽  
Average Serum ◽  
Stimulating Hormone

ABSTRACT The sequence of changes in the serum levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) from 2 days before to 24 h after parturition of primiparous Sprague-Dawley rats was investigated by radioimmunoassay. No appreciable change in average serum FSH levels was observed during 2 days before and 1 h after parturition. After this the levels increased gradually to show a peak at 7 h after parturition and then declined gradually until 24 h after parturition. However, the level at 24 h after parturition was still twice as high as that at parturition (0 h). The average serum LH levels which were low between 2 days before and 1 h after parturition, showed a peak at 7 h and decreased toward 13 h after parturition. The same levels as at parturition were maintained between 13 and 24 h after parturition. The time of surge of either FSH or LH was closely related to the time after parturition. There were some differences between FSH and LH in the patterns of sequence of changes in the serum levels near parturition.

Lung Cancer Incidence After Exposure of Rats to Low Doses of Radon: Influence of Dose Rate

1994 ◽  
Vol 56 (1-4) ◽  
pp. 93-97 ◽  
Author(s):  
J.P. Morlier ◽  
M. Morin ◽  
G. Monchaux ◽  
P. Fritsch ◽  
J.F. Pineau ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Dose Rate ◽  
Cancer Incidence ◽  
Lung Cancer Incidence ◽  
Sprague Dawley ◽  
Survival Times ◽  
Radon Exposure ◽  
Sprague Dawley Rats ◽  
Low Levels ◽  
And Control

Abstract To study the effect on lung cancer incidence of a long exposure to low levels of radon, 500 male 3-month-old Sprague-Dawley rats, were exposed to a cumulative dose of 25 WLM of radon and its daughters, 6 hours a day, 5 days a week, during 18 months. Exposure conditions were controlled in order to maintain a defined PAEC: 42 x 10-6 J.m-3 (2 WL), in the range of domestic and environmental exposures. Animals were kept until they died or given euthanasia when moribund. Mean survival times were similar in both irradiated and control groups: 828 days (SD = 169) and 830 days (SD = 137), as well as lung cancer incidence, 0.60% at 25 WLM and 0.63% for controls. The incidence of lung lesions was compared statistically with controls and those previously obtained at cumulative exposures of 25 and 50 WLM delivered over a 4-6 month period, inducing a significant increase of lung cancer, 2.2% and 3.8% respectively. Such a comparison showed a decreased lung cancer incidence related to a decrease in the dose rate for low levels of radon exposure.

Adrenal progesterone facilitates the negative feedback of oestrogen on LH release in ovariectomized rats

1993 ◽  
Vol 139 (2) ◽  
pp. 253-258 ◽  
Author(s):  
A. M. Salicioni ◽  
R. W. Carón ◽  
R. P. Deis
Keyword(s):  
Ovariectomized Rats ◽  
Adrenal Steroids ◽  
Serum Progesterone ◽  
Oestrogen Treatment ◽  
Ovx Rats ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Lh Secretion

ABSTRACT There is evidence that the adrenals play a role in the regulation of the synthesis and release of gonadotrophins in various vertebrates. The aim of this study was to determine the part played by adrenal steroids, with special reference to progesterone, on the concentration of LH in ovariectomized (OVX) and oestrogen-primed rats. OVX rats received a single s.c. injection of vehicle or oestradiol benzoate (OB, 20 μg/rat). This day was designated as day 0. Three or four days later (day 3–day 4), the rats were treated with mifepristone (10 mg/kg) or with two doses of progesterone antiserum and blood samples were obtained at 13.00 and 18.00 h. OB treatment of OVX rats reduced serum LH at 13.00 h and 18.00 h on day 3 but only at 13.00 h on day 4. The administration of mifepristone at 08.00 h to OVX and oestrogen-treated rats induced a significant increase in serum LH at 18.00 h on days 3 and 4, without modifying the values at 13.00 h. When mifepristone was given at 13.00 h a much larger increase in serum LH was obtained at 18.00 h. In OVX and oestrogen-treated rats, adrenalectomy on day 2 (08.00–09.00 h) induced an increase in serum LH at 18.00 h similar to that observed in the OVX and oestrogen-primed rats after mifepristone treatment. In order to determine the specificity of the effect of mifepristone, a group of OVX and oestrogentreated rats was injected with progesterone antiserum at 08.00 and 13.00 h on day 3. Serum LH concentrations at 13.00 and 18.00 h on day 3 were similar to values obtained in OVX rats treated with oestrogen and mifepristone. Serum progesterone was measured at 08.00 and 13.00 h in OVX and OVX and oestrogenprimed rats. At both times, values were similar in OVX rats but oestrogen treatment significantly increased serum progesterone levels. The important role of adrenal progesterone on the regulation of LH secretion in OVX and oestrogen-primed rats is evident from these results. Blocking progesterone action at the receptor level, we showed that OB significantly increased LH values at 18.00 h. On the basis of these studies it is tempting to speculate on the possibility of an inhibitory or stimulatory effect of oestrogen on serum LH concentration in OVX rats, according to the presence or absence of adrenal progesterone action. Journal of Endocrinology (1993) 139, 253–258

Effects of Electroacupuncture on Uterine Morphology and Expression of Oestrogen Receptors in Ovariectomised Rats

2017 ◽  
Vol 35 (3) ◽  
pp. 208-214 ◽  
Author(s):  
Shulan Ma ◽  
Dongju Li ◽  
Yi Feng ◽  
Jianwei Jiang ◽  
Bo Shen
Keyword(s):  
Steroid Receptors ◽  
Endometrial Thickness ◽  
Serum Levels ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Sham Operation Group ◽  
Reverse Transcription Pcr ◽  
Ovx Rats ◽  
Sprague Dawley Rats ◽  
Unique Effect

Aim To observe the effects of electroacupuncture (EA) on uterine morphology and expression of oestrogen receptor (ER) α and β in ovariectomised (OVX) rats. Methods Thirty female Sprague-Dawley rats with regular 4-day oestrus cycles were divided into a sham operation group (Control, n=10) and two OVX groups that remained untreated (OVX group, n=10) or received EA treatment (OVX+EA group, n=10). In the latter group, EA was applied at CV4, CV3, SP6 and bilateral Zigong (30 min per day) for 3 days. The effects of EA on uterine morphology were observed by H&E staining. Quantitative real-time reverse transcription-PCR (qRT-PCR) and Western blotting were used to measure ERα and ERβ mRNA and protein expression, respectively. Results Relative to the (untreated) OVX group, EA treatment significantly increased the uterine wet weight to body weight (UWW/BW) ratio (0.47±0.04 vs 0.31±0.03 g/kg, p=0.04), and myometrial thickness (109.39±10.71 vs 60.81±8.1 μm, p=0.016) of OVX rats. Similarly, the total number of endometrial glands per cross section and endometrial thickness in the OVX +EA group was significantly increased compared to the (untreated) OVX group. EA treatment also increased protein (but not mRNA) expression of both ERα and ERβ in the uteri of OVX rats. Conclusions This study has demonstrated that EA treatment decreases uterine atrophy in OVX rats. This unique effect of EA on the uterus may be due to upregulation of serum levels of E2 and differential regulation of sex steroid receptors ERα and ERβ.

Inhibition of phasic but not tonic pituitary secretion by 2-hydroxyoestrone in the rat: evidence of action as an oestrogen antagonist

1983 ◽  
Vol 98 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Shigehiro Katayama ◽  
Jack Fishman
Keyword(s):  
Pituitary Hormones ◽  
Ovariectomized Rats ◽  
Priming Dose ◽  
Physiological Mechanisms ◽  
Lh Surge ◽  
Oestradiol Benzoate ◽  
Pituitary Secretion ◽  
The Brain ◽  
Phasic Release

Rats with 4-day oestrous cycles, implanted with intracardiac catheters, were injected with 2-hydroxyoestrone at noon on pro-oestrus and their plasma LH levels monitored at frequent intervals thereafter. A dose of 100 μg 2-hydroxyoestrone completely abolished the preovulatory LH rise in four out of ten animals tested, showing no effect in the six others. When an injection of 10 μg oestradiol 1 h before the 2-hydroxyoestrone administration was given all the rats showed an absence of the preovulatory LH surge, while it remained intact in the controls treated with oestradiol only. The principal metabolite of 2-hydroxyoestrone, 2-methoxyoestrone, exhibited no influence on the pituitary gonadotrophin release. Repeated injections of 100 pg doses of 2-hydroxyoestrone to long-term ovariectomized rats produced no change in plasma LH and prolactin levels. In animals primed with oestradiol benzoate, 2-hydroxyoestrone given 1–2 h after the priming dose blocked the phasic release of the pituitary hormones on the afternoon of the 2 subsequent days. The LH and prolactin surges in the primed animals, however, were not affected when the catechol oestrogen was injected 2 h before their appearance. These results indicate that in the cyclic rat exogenous 2-hydroxyoestrone inhibits the preovulatory LH surge when its administration is coincident with the preovulatory oestradiol rise. In the ovariectomized rat 2-hydroxyoestrone inhibits the oestrogen-dependent priming step but does not affect either the oestrogen-independent expression of the induced surges or the tonic secretion of these pituitary hormones. These results indicate a dissociation of central and peripheral activities in this oestradiol metabolite and suggest that this catechol oestrogen functions as an oestrogen antagonist in neuroendocrine events. Since catechol oestrogens can be formed in the brain these pharmacological responses may reflect physiological mechanisms.

Does oxytocin play a role in the onset of maternal behaviour in the rat?

1984 ◽  
Vol 101 (3) ◽  
pp. 353-357 ◽  
Author(s):  
E. L. M. Bolwerk ◽  
H. H. Swanson
Keyword(s):  
Wistar Rats ◽  
Single Injection ◽  
Rapid Onset ◽  
Maternal Responsiveness ◽  
Control Group ◽  
Maternal Behaviour ◽  
Sprague Dawley ◽  
Untreated Control Group ◽  
Sprague Dawley Rats ◽  
Oestradiol Benzoate

ABSTRACT Oxytocin is released during parturition and may also play a role in maternal behaviour. Oxytocin, injected in the cerebral ventricles, has been reported to accelerate the onset of maternal behaviour in oestrogen-pretreated virgin Sprague—Dawley rats within 2 h of injection. This study was an attempt to replicate and extend these findings in Wistar rats. In the first experiment, 16 virgin females were ovariectomized and a cannula was placed into the cerebral ventricle. Forty-eight hours after a single injection of 24 μg oestradiol benzoate (OB), 400 ng oxytocin or saline were injected into the ventricle. In the second experiment three groups were observed: an untreated control group plus two ovariectomized and cannulated groups treated with OB in a regimen designed to mimic pregnancy. After 10 days of OB administration they received an injection of either saline or oxytocin (400 ng) into the ventricle. Immediately after this injection they were exposed to the pups and observations started. In both experiments no rat became maternal in the first 1·5 h after the intracerebroventricular injection. Oxytocin therefore did not induce a rapid onset of maternal responsiveness in oestrogen-pretreated Wistar rats. J. Endocr. (1984) 101, 353–357

Sign in / Sign up

Export Citation Format

Share Document