Ovarian steroid regulation of angiotensin II-induced water intake in the rat

1999 ◽  
Vol 276 (1) ◽  
pp. R90-R96 ◽  
Author(s):  
Lori R. Kisley ◽  
Randall R. Sakai ◽  
Li Yun Ma ◽  
Steven J. Fluharty
Keyword(s):  
Water Intake ◽  
Peptide Hormone ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
Female Rat ◽  
Ang Ii ◽  
Concurrent Administration ◽  
Ovarian Steroid ◽  
Steroid Administration ◽  
Dose Dependent

Spontaneous water intake as well as thirst elicited by ANG II has been shown to be influenced by the stage of the estrous cycle in the female rat. In these experiments, the contribution of each of the ovarian steroid hormones to the regulation of water intake was examined. Ovariectomized female rats were given replacement doses of estrogen, progesterone, or both, and their responsiveness to an intracerebroventricular injection of ANG II was tested. Forty-eight-hour treatment with estradiol benzoate attenuated ANG II-induced thirst by as much as 70% compared with control animals. The effect of estrogen on drinking was dose dependent and could be completely blocked with concurrent administration of the antiestrogen CI-628. In contrast, progesterone, given alone or after estrogen, did not significantly affect ANG II-induced water intake when animals were tested at 4 or 24 h after steroid administration. A central interaction between the peptide hormone ANG II and estrogen, involving a genomic mechanism, may underlie the cyclicity in water intake behavior observed in the rat.

scholarly journals Estradiol Dose-Dependent Regulation of Membrane Estrogen Receptor-α, Metabotropic Glutamate Receptor-1a, and Their Complexes in the Arcuate Nucleus of the Hypothalamus in Female Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (9) ◽  
pp. 3251-3260 ◽  
Author(s):  
Matthew Mahavongtrakul ◽  
Martha P. Kanjiya ◽  
Maribel Maciel ◽  
Shrey Kanjiya ◽  
Kevin Sinchak
Keyword(s):  
Estrogen Receptor ◽  
Glutamate Receptor ◽  
Arcuate Nucleus ◽  
Metabotropic Glutamate Receptor ◽  
Estradiol Benzoate ◽  
Estrogen Receptor Α ◽  
Female Rats ◽  
Female Rat ◽  
Metabotropic Glutamate ◽  
Dose Dependent

Sexual receptivity in the female rat is dependent on dose and duration of estradiol exposure. A 2 μg dose of estradiol benzoate (EB) primes reproductive behavior circuits without facilitating lordosis. However, 50 μg EB facilitates lordosis after 48 hours. Both EB doses activate membrane estrogen receptor-α (mERα) that complexes with and signals through metabotropic glutamate receptor-1a (mGluR1a). This mERα-mGluR1a signaling activates a multisynaptic lordosis-inhibiting circuit in the arcuate nucleus (ARH) that releases β-endorphin in the medial preoptic nucleus (MPN), activating μ-opioid receptors (MOP). MPN MOP activation is maintained, inhibiting lordosis for 48 hours by 2 μg EB, whereas 50 μg EB at 48 hours deactivates MPN MOP, facilitating lordosis. We hypothesized that 50 μg EB down-regulates ERα and mERα-mGluR1a complexes in the ARH to remove mERα-mGluR1a signaling. In experiment I, 48 hours after 2 μg or 50 μg EB, the number of ARH ERα-immunopositive cells was reduced compared with controls. In experiment II, compared with oil controls, total ARH ERα protein was decreased 48 hours after 50 μg EB, but the 2 μg dose was not. These results indicate that both EB doses reduced the total number of cells expressing ERα, but 2 μg EB may have maintained or increased ERα expressed per cell, whereas 50 μg EB appeared to reduce total ERα per cell. In experiment III, coimmunoprecipitation and Western blot revealed that total mERα and coimmunoprecipitated mERα with mGluR1a were greater 48 hours after 2 μg EB treatment vs rats receiving 50 μg EB. These results indicate 2 μg EB maintains but 50 μg EB down-regulates mERα-mGluR1a to regulate the lordosis circuit activity.

Estradiol attenuates the antidiuretic action of vasopressin in ovariectomized rats

1995 ◽  
Vol 268 (4) ◽  
pp. R951-R957 ◽  
Author(s):  
Y. X. Wang ◽  
J. T. Crofton ◽  
H. Liu ◽  
K. Sato ◽  
D. P. Brooks ◽  
...  
Keyword(s):  
Slow Release ◽  
Tap Water ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Sexually Dimorphic ◽  
Female Rat ◽  
Ovarian Hormone ◽  
Dose Dependent ◽  
Antidiuretic Action

To determine which ovarian hormone is involved in the sexually dimorphic antidiuretic action of vasopressin, the antidiuretic response to vasopressin was examined in sham-operated nonestrous female rats chronically treated with vehicle and in ovariectomized rats treated with vehicle, progesterone, estradiol, or the combination of estradiol and progesterone, respectively. Three-week-old female rats were sham operated or ovariectomized, and a slow-release hormone pellet was implanted at the 6th wk. The experiment was performed at the 10th to 12th wk in conscious, chronically instrumented rats hydrated with tap water (2% body wt). Infusion of vasopressin at rates of 10-1,000 pg.min-1.kg body wt-1 resulted in a dose-dependent antidiuretic response that was significantly enhanced in ovariectomized rats compared with the intact nonestrous females. Progesterone had no effect, whereas estradiol attenuated and restored the antidiuretic response to vasopressin to a level similar to that in intact nonestrous female rats. These results suggest that it is estrogen, but not progesterone, that reduces the antidiuretic response to vasopressin in the female rat.

Role of AT2 receptor in the brain in regulation of blood pressure and water intake

2003 ◽  
Vol 284 (1) ◽  
pp. H116-H121 ◽  
Author(s):  
Zhen Li ◽  
Masaru Iwai ◽  
Lan Wu ◽  
Tetsuya Shiuchi ◽  
Toyohisa Jinno ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Water Intake ◽  
Pressor Response ◽  
Receptor Blocker ◽  
Dependent Manner ◽  
Ang Ii ◽  
Dose Dependent ◽  
Regulation Of Blood Pressure

The effects of intracerebroventricular (ICV) injection of angiotensin II (ANG II) on blood pressure and water intake were examined with the use of ANG II receptor-deficient mice. ICV injection of ANG II increased systolic blood pressure in a dose-dependent manner in wild-type (WT) mice and ANG type 2 AT2 receptor null (knockout) (AT2KO) mice; however, this increase was significantly greater in AT2KO mice than in WT mice. The pressor response to a central injection of ANG II in WT mice was inhibited by ICV preinjection of the selective AT1 receptor blocker valsartan but exaggerated by the AT2 receptor blocker PD-123319. ICV injection of ANG II also increased water intake. It was partly but significantly suppressed both in AT2KO and AT1aKO mice. Water intake in AT2/AT1aKO mice did not respond to ICV injection of ANG II. Both valsartan and PD-123319 partly inhibited water intake in WT mice. These results indicate an antagonistic action between central AT1a and AT2 receptors in the regulation of blood pressure, but they act synergistically in the regulation of water intake induced by ANG II.

Localization of central nervous system structures mediating extracellular thirst in the female rat

1984 ◽  
Vol 100 (2) ◽  
pp. 183-NP ◽  
Author(s):  
J. Kucharczyk
Keyword(s):  
Angiotensin Ii ◽  
Water Intake ◽  
Extracellular Fluid ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Female Rat ◽  
Adrenergic Agonist ◽  
Preoptic Region ◽  
Body Fluid Compartments ◽  
Fluid Compartments

ABSTRACT Water intake elicited by microinjection of the hormone angiotensin-II into the preoptic region of cyclic female rats was significantly less on days of vaginal oestrus than at dioestrus or metoestrus, whereas the drinking of 2·7% NaCl solution, to which rats also had access, did not vary with the cycle. Administration of the same dose of angiotensin-II to the subfornical organ and the lateral cerebral ventricles induced drinking at all stages of the oestrous cycle, but the volumes of water or 2·7% NaCl ingested did not vary with the cycle. Water intake after subcutaneous injection of isoprenaline, a β-adrenergic agonist which causes increased angiotensin biosynthesis, varied cyclically with the stage of the oestrous cycle. On the other hand, water and 2·7% NaCl intakes induced by intraperitoneal injection of hypertonic NaCl (a cellular stimulus of thirst) or by 24-h water deprivation (which dehydrates both the extracellular and cellular body fluid compartments) did not differ significantly at the various stages of the oestrous cycle. The finding that fluctuations in angiotensin- and isoprenaline-induced water intake parallel the changes in spontaneous 24-h drinking suggests that the preoptic region may play an important role in the maintenance of extracellular fluid balance in synchrony with the oestrous cycle. J. Endocr. (1984) 100, 183–188

242 POTENTIAL ESTROGENIC EFFECT(S) OF PARABENS AT THE NEONATAL STAGE OF AN IMMATURE FEMALE RAT MODEL

2010 ◽  
Vol 22 (1) ◽  
pp. 279
Author(s):  
S. H. Hyun ◽  
E. B. Jeung
Keyword(s):  
Body Weight ◽  
Rat Model ◽  
Estrogenic Activity ◽  
Female Rats ◽  
Female Rat ◽  
Dependent Manner ◽  
Methyl Ethyl ◽  
Immature Female ◽  
Immature Rats ◽  
Dose Dependent

In this study, to examine the estrogenic activity effects of parabens on hormonal responsiveness and on change in the morphology of reproductive target tissues during a critical development stage in female rats, analyses for parabens including methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutylparaben were performed in an immature female Sprague-Dawley rat model. Two hundred female immature rats (n = 10/group) were orally treated with these parabens from postnatal day 21 to 40 in a dose-dependent manner based on our previous study [62.5, 250, and 1000 mg/kg of body weight (BW) per day]. 17α-ethinylestradiol (EE;1 mg/kg of BWper day) was used as a positive control and corn oil as a vehicle.A high doseofmethyl- and isopropylparaben (1000 mg/kg of BW per day) resulted in a significant delay in the date of vaginal opening and a decrease in length of the estrous cycle (P < 0.05). In measurements of organ weight and body weight, we observed significant weight changes in ovaries, adrenal glands, thyroid glands, liver, and kidneys(P < 0.05); conversely, body weight was not altered following paraben treatment. In all groups exposedto paraben treatment, histological analysis of the ovaries from the immature rats revealed interstitial cell disorders, a lack of corpora lutea, an increase in the number of cystic follicles, and thinning of the follicular epithelium, which occurred in a dose-dependent manner. In addition, morphological studies of the uterus revealed the myometrial dysplasia suchas myometrial hyperplasia inthe high-doseofpropyl- and isopropylparaben (1000 mg/kgof BWper day) group and in all dose of butyl- and isobutylparabens groups. We also observed a significant decrease in serum estradiol and T4 concentrations in methyl-, ethyl-, propyl-, isopropyl-, and isobutylparaben-treated groups (P < 0.01 and 0.05).A receptor-binding assay indicated that the relative binding affini- ties of parabens to estrogen receptors occurred in the order: isobutylparaben > butylparaben > isopropylparaben = propylparaben > ethylparaben. These values were much less than the binding affinity for 17?-estradiol. Taken together, long-term exposure to parabens, which show less estrogenic activity than EEl, can produce suppressive effects on hormonal responsiveness and can disrupt the morphology of reproductive target tissues during this critical stage of development in immature female rats.

scholarly journals The Effects of Chronic Administration of Testosterone Propionate with or without Estradiol on the Sexual Behavior and Plasma Steroid Levels of Aged Female Rats

Endocrinology ◽  
2012 ◽  
Vol 153 (12) ◽  
pp. 5928-5939 ◽  
Author(s):  
Sherri Lee Jones ◽  
Nafissa Ismail ◽  
Leonora King ◽  
James G. Pfaus
Keyword(s):  
Sexual Behavior ◽  
Sexual Behaviors ◽  
Sexual Desire ◽  
Chronic Treatment ◽  
Testosterone Propionate ◽  
Chronic Administration ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
Second Phase ◽  
Female Rat

Abstract Low sexual desire concomitant with feelings of distress is reported in naturally and surgically menopausal women. A combination of estradiol (E2) and testosterone (T) restores sexual desire and interest in these women. The central mechanisms by which E2 and T act to restore desire are poorly understood. Here we examined the effect of chronic treatment with testosterone propionate (TP) administered by a sc SILASTIC brand capsule in aged ovary-intact female rats. Females were first treated with TP alone, followed by a second phase when TP was administered in combination with estradiol benzoate (EB; 10 μg) by sc injection 48 h prior to testing (EB+TP). Each phase consisted of 5 test days at 4-d intervals. Appetitive and consummatory female sexual behaviors were observed in bilevel chambers, and plasma E2 and T concentrations were measured with ELISA. Sexual solicitations and hops and darts were facilitated by the highest TP dose, and the lordosis quotient was increased by the two highest TP doses when administered alone, coinciding with an increase in plasma T, but those behavioral effects were not maintained across time. The lordosis quotient was inversely related to the TP dose in the EB+TP phase. These results suggest that the administration of TP by sc capsules to aged female rats facilitates appetitive and consummatory sexual behaviors; however, chronic treatment appears to be inhibitory. This is the first study to assess sexual behavior after SILASTIC brand implants of TP in the aged female rat. Additional research is needed to elucidate the mechanisms underlying the effects of T on female sexual function.

scholarly journals Selective inhibition of angiotensin receptor signaling through Erk1/2 pathway by a novel peptide

2014 ◽  
Vol 306 (8) ◽  
pp. R619-R626 ◽  
Author(s):  
Jun Liu ◽  
Gina L. C. Yosten ◽  
Hong Ji ◽  
Dan Zhang ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Water Intake ◽  
Selective Inhibition ◽  
Female Rats ◽  
Ang Ii ◽  
Exon 2 ◽  
Reading Frame ◽  
Amino Acid Peptide ◽  
Male And Female Rats

A seven-amino acid peptide (PEP7) is encoded within a short open reading frame within exon 2 (E2) in the 5′-leader sequence (5′LS) upstream of the rat ANG 1a-receptor (rAT1aR) mRNA. A chemically synthesized PEP7 markedly inhibited ANG II-induced Erk1/2 activation in cell culture by 62% compared with a scrambled PEP7 (sPEP7) [pErk1/2/Erk1/2 (AU): ANG II, 1.000 ± 0.0, ANG II+PEP7, 0.3812 ± 0.086, ANG II+sPEP7, 1.069 ± 0.18; n = 3]. Under these same conditions, PEP7 had no effect on ANG II-stimulated inositol-trisphosphate production. PEP7 also had no effect on epidermal growth factor- and phorbol methyl ester-induced Erk1/2 activation, suggesting PEP7 selectively inhibits AT1aR-mediated Erk1/2 signaling. PEP7 intracerebroventricularly inhibited ANG II-induced saline intake but had no effect on water intake in male and female rats, indicating PEP7 also selectively inhibits the ANG II-Erk1/2 pathway in vivo since saline drinking is Erk1/2-mediated, while water drinking is not. PEP7 inhibition of ANG II-induced saline ingestion was rapidly reversed by a subsequent intracerebroventricular injection of an oxytocin antagonist, suggesting when PEP7 blocks ANG II-stimulated Erk1/2 activation, animals no longer ingest saline to balance the continued water intake, due to the release of oxytocin and its subsequent inhibitory effects on saline drinking. PEP7 also attenuated ANG II-induced increases in arterial pressure by 35% compared with sPEP7 at the same dose. Thus, we have identified a novel peptide encoded within the rAT1aR E2 that selectively inhibits Erk1/2 activation, resulting in physiological consequences for sodium ingestion and arterial pressure that may have implications for treating sodium-sensitive diseases like hypertension and chronic kidney disease.

scholarly journals Septopreoptic μ Opioid Receptor Mediation of Hindbrain Glucoprivic Inhibition of Reproductive Neuroendocrine Function in the Female Rat

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 5322-5331 ◽  
Author(s):  
Sushma R. Singh ◽  
Karen P. Briski
Keyword(s):  
Transcriptional Activation ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
Neural Pathways ◽  
Female Rat ◽  
Transcriptional Responses ◽  
Neuron Populations ◽  
Regulatory Effects ◽  
Maximal Induction ◽  
Genomic Response

Abstract Central glucostasis is a critical monitored variable in neuroendocrine regulation of pituitary LH secretion. Glucoprivic signals originating within the caudal hindbrain suppress LH. Septopreoptic μ opioid receptors (μ-R) function within neural pathways maintaining basal LH levels and mediate the effects of diverse physiological stimuli on hormone release. To identify potential sites in the septopreoptic area where ligand neuromodulatory actions may occur in response to hindbrain glucoprivic signaling, the present studies evaluated the distribution of μ-R-immunoreactive (-ir) neurons in the septopreoptic area that are genomically activated in response to caudal fourth ventricular (CV4) delivery of the glucose antimetabolite, 5-thioglucose (5TG). The effects of lateral ventricular pretreatment with the selective μ-R antagonist, d-Phe-Cys-Tyr-d-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), on LH secretory and GnRH neuronal transcriptional responses to hindbrain glucoprivation were also evaluated. Estradiol benzoate- and progesterone-primed, ovariectomized female rats were treated by CV4 administration of 5TG or the vehicle, saline, at the onset of the afternoon LH surge. The inhibitory effects of hindbrain glucoprivation on mean plasma LH levels as well as colabeling of rostral preoptic GnRH neurons for Fos-ir were attenuated in animals pretreated by lateral ventricular delivery of CTOP. Dual immunocytochemical labeling for septopreoptic μ-R-ir and Fos-ir demonstrated a robust induction of Fos expression by receptor-positive neurons within discrete septopreoptic sites in response to CV4 5TG, a genomic response that was diminished by CTOP pretreatment. The current studies provide novel evidence for the transcriptional activation of neuroanatomically characterized, μ-R-expressing neurons by decreased hindbrain glucose utilization and show that the functional status of μ-R is critical for maximal induction of the Fos stimulus-transcription cascade in these cells by central glucoprivic signaling. The finding that receptor antagonist-mediated suppression of this genomic response is correlated with increased reproductive neuroendocrine output supports a role for these discrete μ-R-expressing neuron populations as substrates for ligand regulatory effects on the GnRH-pituitary LH axis during neuroglucopenia.

Renal responses to oxytocin during the 4 days of the oestrous cycle in the rat

1997 ◽  
Vol 154 (2) ◽  
pp. 347-353 ◽  
Author(s):  
R J Windle ◽  
M L Forsling
Keyword(s):  
Sodium Excretion ◽  
Dose Range ◽  
Virgin Female ◽  
Urine Flow ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Female Rat ◽  
Oxytocin Infusion ◽  
Renal Responses ◽  
Dose Dependent

Abstract Oxytocin was administered to virgin female rats at doses of 25–200 pmol/min during 0·077 mol NaCl/l infusion at 150 μl/min on each day of the oestrous cycle. The resultant rates of urine flow, glomerular filtration (GFR) and electrolyte excretion were determined. Oxytocin caused significant increases in urine flow (P<0·001) and sodium excretion (P<0·001); both responses being dose-dependent (P<0·02 and P<0·01 respectively). Significant variations in the renal responsiveness to the hormone occurred over the 4 days of the oestrous cycle. On oestrus the lowest dose of 25 pmol oxytocin/min produced a significant increase in urine flow (from 139·5 ± 4·3 to 165·6 ± 7·1 μl/min, P<0·005) and a dose of 50 pmol/min produced a significant increase in sodium excretion (from 10·6 ± 0·1 to 14·5 ± 0·7 μmol/min, P<0·005). Significant increases in urine flow and sodium excretion were seen on pro-oestrus with hormone administration rates of 50 and 100 pmol/min respectively and on dioestrus day 2 with a rate of 100 pmol/min. On dioestrus day 1 no increase in urine flow or sodium excretion was seen over the dose range of oxytocin administration. A dose of 100 pmol oxytocin/min significantly increased GFR on pro-oestrus and dioestrus day 2, but not on the other 2 days of the cycle. The circulating hormone concentrations produced by oxytocin infusion were similar on each day of the cycle and so could not account for the differences seen. Therefore, these results suggest varying renal responsiveness to oxytocin during the reproductive cycle of the female rat. Journal of Endocrinology (1997) 154, 347–353

Modification of Pineal Ultrastructure by Exogenous Hormones

1967 ◽  
Vol 25 ◽  
pp. 170-171
Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
List Type ◽  
Type Number ◽  
Pregnant Rats ◽  
Gonadal Atrophy ◽  
Pineal Ultrastructure

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.

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