Systemic NOS inhibition reduces contracting muscle oxygenation more in intact female than male rats

Nitric Oxide ◽  
2020 ◽  
Vol 100-101 ◽  
pp. 38-44
Author(s):  
Ayaka Tabuchi ◽  
Jesse C. Craig ◽  
Daniel M. Hirai ◽  
Trenton D. Colburn ◽  
Yutaka Kano ◽  
...  
Keyword(s):  
Muscle Oxygenation ◽  
Male Rats ◽  
Intact Female ◽  
Contracting Muscle

INFLUENCE OF STEROID SEX HORMONES ON THE F. S. H.-RELEASE BY RAT HYPOPHYSES IN VITRO

1961 ◽  
Vol 36 (4) ◽  
pp. 485-497 ◽  
Author(s):  
G. P. van Rees
Keyword(s):  
Sex Hormones ◽  
Female Rats ◽  
Male Rats ◽  
Intact Female ◽  
Intact Male ◽  
Incubation Experiments ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Steroid Sex Hormones

ABSTRACT The hypothesis that steroid sex hormones influence pituitary F. S. H. by independent actions on its production and capacity of the gland to release it has been investigated by means of incubation experiments. During incubation, rat pituitary glands released considerable amounts of F. S. H. into the medium. Inactivation of F. S. H. during incubation could not be demonstrated; once (in females) some production of F. S. H. was even observed. The amount of F. S. H. which is released into the medium is influenced by the quantity of F. S. H. stored in the hypophyses. Hypophyses from male rats pretreated with oestradiol released relatively more F. S. H. into the medium than hypophyses from control animals. On the other hand, pretreatment with testosterone caused the pituitary glands to release less F. S. H. into the medium. In agreement with these results, hypophyses from intact male rats released relatively less F. S. H. than hypophyses from intact female rats. These facts support the hypothesis that androgens depress pituitary F. S. H.-secretion by inhibiting the capacity to release it, while oestrogens, which can even promote this property of the pituitary gland, also act by directly inhibiting its production.

Incidence, growth and oestradiol-receptor levels of 7,12-dimethylbenz(a)anthracene-induced mammary tumours in rats: effects of neonatal sex steroids and oestradiol implants

1982 ◽  
Vol 95 (3) ◽  
pp. 357-368 ◽  
Author(s):  
G. Verhoeven ◽  
G. Vandoren ◽  
W. Heyns ◽  
E. R. Kühn ◽  
J. P. Janssens ◽  
...  
Keyword(s):  
Female Rats ◽  
Male Rats ◽  
Intact Female ◽  
Intact Male ◽  
Tumour Incidence ◽  
Tumour Induction ◽  
Male And Female Rats ◽  
Neonatal Administration ◽  
Low Levels ◽  
Intact Rats

The effects of neonatally administered steroids on the sensitivity of the mammary gland to tumour induction by 7,12-dimethylbenz(a)anthracene was studied as a model for delayed (de)differentiating effects of steroid hormones. Immediately after birth male and female rats were gonadectomized and treated with testosterone, oestradiol or oil. Control animals were left intact. On day 45 all the gonadectomized animals and some of the control animals received an implant which delivered continuous low levels of oestradiol. The carcinogen was administered on day 55. The administration of an oestradiol implant, which increased prolactin levels in all animals, markedly reduced tumour incidence in intact female rats and increased tumour incidence in intact male rats. Neonatal administration of testosterone or oestradiol did not significantly influence tumour incidence, histopathology or oestradiol responsiveness in neonatally gonadectomized rats but tended to decrease tumour oestradiol-receptor levels. This lack of effect of neonatal steroids in gonadectomized animals suggests that the effects observed by other authors in intact rats are mediated by changes in gonadal secretions. It is concluded that the hormonal environment during and after tumour induction plays a major role in the development of 7,12-dimethylbenz(a)anthracene-induced mammary carcinomas.

Induction of the gonadotrophin surge-inhibiting factor by FSH and its elimination: a sex difference in the efficacy of the priming effect of gonadotrophin-releasing hormone on the rat pituitary gland

1993 ◽  
Vol 138 (2) ◽  
pp. 191-201
Author(s):  
D. W. Koppenaal ◽  
J. A. M. J. van Dieten ◽  
A. M. I. Tijssen ◽  
J. de Koning
Keyword(s):  
Body Weight ◽  
Pituitary Gland ◽  
Priming Effect ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
Pulse Interval ◽  
Intact Female ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

ABSTRACT This study was designed to explore the efficacy of gonadotrophin-releasing hormone (GnRH) to antagonize the effect of gonadotrophin surgeinhibiting factor (GnSIF) on the timing of the induction by GnRH of the maximal self-priming effect on pituitary LH responsiveness. The GnSIF levels were increased by FSH treatment and reduced after gonadectomy. Female rats were injected s.c. with 10 IU FSH or saline (control) on three occasions during the 4-day cycle. Serial i.v. injections of GnRH (500 pmol/kg body weight) were administered to intact rats on the afternoon of pro-oestrus or 15–30 min after ovariectomy. Intact male rats were given 10 IU FSH and 500 or 2000 pmol GnRH/kg body weight on an equivalent time-schedule. Endogenous GnRH release was suppressed with phenobarbital. In intact female control rats, the timing of the maximally primed LH response was delayed as the GnRH pulse-interval increased. FSH treatment of female rats induced a suppression of the initial unprimed LH response and delayed the maximally primed LH response, which showed further delay as the GnRH pulse-interval was increased. When the pulsatile administration of GnRH was started 15–30 min after ovariectomy, the priming effect of GnRH did not change as the GnRH pulse-interval was increased in the saline-treated rats. However, FSH treatment caused a suppression of the unprimed LH response, a delay in the primed LH response and decreased the delay of the maximally primed LH response to GnRH when the GnRH pulse-interval was decreased. Increasing the interval between ovariectomy and the first GnRH pulse to 4 h diminished the efficacy of the FSH treatment: GnRH-induced priming was delayed by only one pulse instead of the two pulses in control rats. In intact males but not in orchidectomized rats, a self-priming effect was demonstrated during GnRH pulses which were 1 h apart. The effect of 2 nmol GnRH/kg body weight was the most pronounced. Compared with intact female rats, the timing of the maximally primed LH response was delayed by 1 h. FSH treatment did not affect the pituitary LH response to both dose levels of GnRH. It is concluded that FSH treatment increased the release of GnSIF by the ovary, then induced a state of low responsiveness of the pituitary gland to GnRH and subsequently delayed GnRH-induced maximal self-priming. The efficacy of GnRH to prime the pituitary gland was higher when GnSIF levels were decreasing after removal of the ovaries. On the other hand, GnSIF was more effective when the GnRH pulse-interval was increasing. This allows GnSIF more time to restore the unprimed state of the pituitary gland after each GnRH pulse-induced self-priming effect. It remains a matter of debate whether a similar mechanism of action is present in the male rat or whether this mechanism is suppressed by endogenous hormones such as androgens. Journal of Endocrinology (1993) 138, 191–201

Effects of sex and exercise training on β-adrenoreceptor mediated opposition of evoked sympathetic vasoconstriction in resting and contracting muscle of rats

2020 ◽  
Author(s):  
Ian R. Cooper ◽  
Sixue Liu ◽  
Darren S. DeLorey
Keyword(s):  
Exercise Training ◽  
Triceps Surae ◽  
Female Rats ◽  
Male Rats ◽  
Sprague Dawley ◽  
Contracting Muscle ◽  
Arterial Blood ◽  
Male And Female Rats ◽  
Sympathetic Vasoconstriction ◽  
Main Effect

This study investigated the hypothesis that β-adrenoreceptor mediated inhibition of sympathetic vasoconstriction would be enhanced in female compared to male rats, and that exercise training would augment β-adrenoreceptor inhibition of sympathetic vasoconstriction in male and female rats. Sprague-Dawley rats were randomized into sedentary (Male: n=7; Female: n=8) and exercise trained (Male: n=9; Female: n=9) groups. Following 4 weeks of exercise training or sedentary behavior, rats were anesthetized and surgically instrumented for stimulation of the lumbar sympathetic chain, muscle contraction and measurement of arterial blood pressure and femoral artery blood flow (FBF). Femoral vascular conductance (FVC) was calculated as FBF/mean arterial pressure. The percentage change of FVC in response to sympathetic stimulation delivered at 2 and 5 Hz was measured at rest and during contraction of the triceps surae muscles before and after β-adrenoreceptor blockade (Propranolol;0.075 mg·kg-1, IV). We found that, at rest, β-adrenoreceptor blockade decreased (main effect of drug, 2Hz: P <0.001; 5Hz: P<0.001) sympathetic vasoconstriction. During contraction, sympathetic vasoconstrictor responsiveness was lower (main effect of sex, 2Hz: P=0.001; 5Hz: P=0.023) in female compared to male rats, and sympatholysis was enhanced (main effect of sex, 2 Hz: P=0.001; 5Hz: P<0.001) in female rats. β-adrenoreceptor blockade decreased (main effect of drug, 2Hz: P=0.049; 5Hz: P<0.001) evoked sympathetic vasoconstriction in contracting muscle. The present study demonstrated that β-adrenoreceptors do not blunt sympathetic vasoconstriction in resting or contracting skeletal muscle of male or female rats. Sympatholysis was enhanced in female rats, however, this was not attributable to β-adrenoreceptor mediated blunting of sympathetic vasoconstriction.

EFFECT OF OVARIAN STEROIDS ON PREPUTIAL GLAND ODOURS IN THE FEMALE RAT

1978 ◽  
Vol 77 (3) ◽  
pp. 397-403 ◽  
Author(s):  
A. J. THODY ◽  
H. DIJKSTRA
Keyword(s):  
Single Injection ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Whole Body ◽  
Female Rat ◽  
Preputial Gland ◽  
Intact Female ◽  
Oestradiol Benzoate ◽  
Experienced Male

Sexually experienced male rats were used to test for whole body and preputial gland odours of female rats. The male rats clearly preferred whole body odours of intact female rats to those of preputialectomized female rats. The male rats also preferred the odour of preputial gland tissue of intact female rats to that of ovariectomized female rats and were especially attracted to the preputial gland odours of female rats in pro-oestrus and oestrus. The preputial gland odours of ovariectomized rats that had received oestradiol benzoate for 7 days were attractive to male rats, although similar treatment with progesterone was ineffective. However, a single injection of progesterone given 72 h after a single injection of oestradiol benzoate not only made ovariectomized rats receptive, but also made their preputial gland odours attractive to male rats. The results suggest that the preputial gland of the female rat is responsible for odours that serve to attract sexually experienced male rats. Ovarian steroids, as well as controlling receptivity in the female rat, would also appear to control the production of sex attractants in the preputial gland. There was no relationship between the size of the preputial glands and their ability to attract male rats which suggests that preputial gland growth and production of sex attractants are not under the same hormonal control.

A CRITICAL PERIOD FOR POSITIVE FEEDBACK IN IMMATURE (21-DAY-OLD) RATS

1978 ◽  
Vol 76 (2) ◽  
pp. 311-320 ◽  
Author(s):  
E. PUIG-DURAN ◽  
P. C. B. MACKINNON
Keyword(s):  
Total Concentration ◽  
Maximum Level ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Intact Female ◽  
Intact Male ◽  
Initial Injection ◽  
Old Rats ◽  
Prolactin Response

The concentrations of LH and prolactin in the serum in response to a single s.c. injection of oestradiol benzoate (OB, 1 μg) were studied in 21-day-old Wistar rats of different sexual status. In intact female rats, the total concentration of oestrogen in the serum reached a maximum level within 30 min of the injection, whereas the level of LH fell and remained low until a surge occurred 54 h later. However, the amount of prolactin in the serum increased within 1 h of injection of OB and thereafter showed diurnal fluctuations with evening peaks. Male rats castrated within 24 h of birth showed increases in the serum level of both LH and prolactin in response to OB, which were similar in timing to those seen in intact female rats. However, intact male rats failed to show an increase in the level of either LH or prolactin after treatment with OB, while neonatally androgenized female rats, although failing to show an increase in the level of LH, exhibited a prolactin response which was similar to that observed in intact female rats. A further study was undertaken in rats which had received an initial injection of OB and a subsequent injection of progesterone 5 h before the expected female-type LH surge. In intact female rats, progesterone augmented the oestrogen-stimulated surge of LH, but this effect was not observed in either intact male or neonatally androgenized female rats. In all three groups, however, the level of prolactin in the serum was increased when compared with control animals which had received OB only. The effect of progesterone, injected at various times after priming with OB, on the output of LH and prolactin was also studied in female rats killed 5 h after the second injection. Up to 21 h after injection of OB, progesterone had no effect on the level of LH or prolactin. If, however, progesterone was then injected during the middle of the light period, but not in the dark period, the concentrations of LH and prolactin increased. Thus there are critical times during a 24 h period when the gonadotrophin output of the oestrogen-primed female rat is responsive to the stimulatory effects of progesterone.

EFFECTS OF OESTRADIOL AND PROGESTERONE ON THE CONCENTRATION OF α2-MACROGLOBULIN IN THE SERA OF INJURED MALE AND FEMALE RATS

1980 ◽  
Vol 86 (1) ◽  
pp. 189-191 ◽  
Author(s):  
S. C. BELL
Keyword(s):  
Tissue Injury ◽  
Ovarian Hormones ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Intact Female ◽  
Male And Female Rats ◽  
Α2 Macroglobulin ◽  
The Mean

The effects of ovarian hormones on the synthesis of α2-macroglobulin in response to injury were investigated. After injection of turpentine to provoke synthesis of α2-macroglobulin, the mean concentrations of this protein in serum were lower in intact female than in male rats. Sera from injured ovariectomized rats contained levels of α2-macroglobulin similar to those of injured male animals. Administration to ovariectomized animals of oestradiol or oestradiol plus progesterone substantially reduced the levels of α2-macroglobulin produced in response to injury. Administration of progesterone only resulted in a small increase in the response of ovariectomized animals to injury. Oestradiol and progesterone had no effect on the response of male rats to injury. These findings suggest that only in the female rat can these steroid hormones, especially oestradiol, regulate the synthesis of α2-macroglobulin in response to tissue injury.

Gender difference in bioassayable endothelium-derived nitric oxide from isolated rat aortae

1994 ◽  
Vol 267 (6) ◽  
pp. H2311-H2317 ◽  
Author(s):  
K. Kauser ◽  
G. M. Rubanyi
Keyword(s):  
Nitric Oxide ◽  
Wistar Rats ◽  
Isometric Tension ◽  
Female Rats ◽  
Male Rats ◽  
Intact Female ◽  
Male And Female ◽  
Male And Female Rats ◽  
Female Wistar Rats ◽  
Endothelium Dependent Relaxation

Gender differences in the production/release of endothelium-derived nitric oxide (EDNO) was assessed by determining the ability of intact endothelium to suppress serotonin- (10(-7)-10(-5) M) and phenylephrine-induced (10(-9)-(10(-5) M) contractions in thoracic aortae isolated from male and female Wistar rats mounted in organ chambers for isometric tension recording or tested in bioassay experiments. The endothelium suppressed these contractions significantly more in aortae from female than from male rats. In the bioassay, the perfusate from intact female thoracic aortic segments produced a significantly greater relaxation of the detector rings than that from the aortae isolated from male rats. Acetylcholine (10(-9)-10(-5) M), used to investigate agonist-induced release of EDNO, evoked significantly greater endothelium-dependent relaxation in aortae from female rats. The unstimulated release of 6-ketoprostaglandin F1 alpha and thromboxane B2 from intact thoracic aortic rings from male and female rats was not significantly different. There was no difference in smooth muscle reactivity to sodium nitroprusside (10(-10)-10(-6) M) in rings without endothelium. These results indicate that EDNO production/release is higher in thoracic aortae isolated from female rats.

scholarly journals Study of Reproductive Toxicity of the Liposomal Photosensitizer Lipophthalocyan

Drug Research ◽  
2021 ◽  
Author(s):  
Olga Konyaeva ◽  
Nataliya Kulbachevskaya ◽  
Vera Chaley ◽  
Nadezhda Ermakova ◽  
Pavel Varaksa ◽  
...  
Keyword(s):  
Fetal Death ◽  
Reproductive Toxicity ◽  
Reproductive Function ◽  
Female Rats ◽  
Male Rats ◽  
Control Group ◽  
Intact Female ◽  
Embryotoxic Effect ◽  
Negative Effect ◽  
Post Implantation

Abstract Objective Study of embryotoxicity, teratogenicity and reproductive toxicity of the new drug Lipophtalocyan in rats. Material and Methods Studies were conducted on 210 non-inbred female rats and 105 non-inbred male rats. The drug was administered daily via i. v. injection for 48 days (males) and for 15 days (females) in 2 total doses corresponding to the therapeutic dose (TD) for mice when converted to rats and 10 TD. Results and Conclusion When mating with intact female rats, no changes in sexual behavior were observed, but the index of the ability to fertilize and conceive decreased when compared to the values of the control group by 35–40% (TD index=60%) and by 75–80% (10 TD index=20%). The index of the ability to fertilize and conceive differed from the values of the control group by 90% (TD index=5%) and by 15% (10 TD index=80%). There were no differences in the indicator of embryotoxicity and teratogenicity in intact and drug-treated female rats, compared with the control group. Lipophtalocyan has a negative effect on the male and female reproductive function in rats and has an embryotoxic effect according to the index of the ability to fertilize and conceive, as well as the indices of preimplantation and post-implantation fetal death. The drug does not have a teratogenic effect, neither it affects the physical development of offspring or the rate of maturation of sensory-motor reflexes during feeding.

scholarly journals Valproic Acid Inhibits NA-K-2CL Cotransporter RNA Expression in Male But Not in Female Rat Thymocytes

Dose-Response ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 155932581985244
Author(s):  
Milda Juknevičienė ◽  
Ingrida Balnytė ◽  
Angelija Valančiūtė ◽  
Vaiva Lesauskaitė ◽  
Jurate Stanevičiūtė ◽  
...  
Keyword(s):  
Polymerase Chain Reaction Method ◽  
Male Rats ◽  
Female Gonad ◽  
Rna Expression ◽  
Female Rat ◽  
Chain Reaction ◽  
Intact Female ◽  
Intact Male ◽  
Pharmacological Studies ◽  
Polymerase Chain

Objective: The NKCC1 is a recognized tumorigenesis marker as it is important for tumor cell proliferation, differentiation, apoptosis, and tumor progression. The study aim was to investigate the effect of sodium valproate (VPA) on thymus NKCC1 RNA expression. Material and Methods: Wistar rats, age 4 to 5 weeks, were investigated in the control and VPA-treated male and female gonad-intact and castrated groups. The treatment duration with VPA 300 mg/kg/d was 4 weeks. Rat thymus was weighted; its lobe was taken for the expression of NKCC1 RNA determined by the real-time polymerase chain reaction method. Results: The RNA expression of the Slc12a2 gene was found to be significantly higher in the gonad-intact male control compared with the gonad-intact female control ( P = .04). There was a gender-related VPA treatment effect on NKCC1 RNA expression in thymus: The Slc12a2 gene RNA expression level was found to be decreased in VPA-treated gonad-intact males ( P = .015), and no significant VPA effects were found in the castrated males and in the gonad-intact and castrated females compared with the respective controls ( P > .05). Conclusions: The study showed a gender-related difference in the NKCC1 RNA expression in rat thymus. The VPA decreases the NKCC1 expression in the thymus only in gonad-intact male rats. The NKCC1 RNA expression downregulation by VPA could be important for further VPA pharmacological studies in oncology.

Sign in / Sign up

Export Citation Format

Share Document