scholarly journals Neonatal handling and reproductive function in female rats

2005 ◽  
Vol 184 (2) ◽  
pp. 435-445 ◽  
Author(s):  
C M Gomes ◽  
C Raineki ◽  
P Ramos de Paula ◽  
G S Severino ◽  
C V V Helena ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Plasma Levels ◽  
Preoptic Area ◽  
Reproductive Function ◽  
Female Rats ◽  
Estrous Cycles ◽  
Neonatal Handling ◽  
Environmental Stimulation ◽  
Medial Septal Area ◽  
Lh Releasing Hormone

Neonatal handling induces anovulatory estrous cycles and decreases sexual receptivity in female rats. The synchronous secretion of hormones from the gonads (estradiol (E2) and progesterone (P)), pituitary (luteinizing (LH) and follicle-stimulating (FSH) hormones) and hypothalamus (LH-releasing hormone (LHRH)) are essential for the reproductive functions in female rats. The present study aimed to describe the plasma levels of E2 and P throughout the estrous cycle and LH, FSH and prolactin (PRL) in the afternoon of the proestrus, and the LHRH content in the medial preoptic area (MPOA), median eminence (ME) and medial septal area (MSA) in the proestrus, in the neonatal handled rats. Wistar pup rats were handled for 1 min during the first 10 days after delivery (neonatal handled group) or left undisturbed (nonhandled group). When they reached adulthood, blood samples were collected through a jugular cannula and the MPOA, ME and MSA were microdissected. Plasma levels of the hormones and the content of LHRH were determined by RIA. The number of oocytes counted in the morning of the estrus day in the handled rats was significantly lower than in the nonhandled ones. Neonatal handling reduces E2 levels only on the proestrus day while P levels decreased in metestrus and estrus. Handled females also showed reduced plasma levels of LH, FSH and PRL in the afternoon of the proestrus. The LHRH content in the MPOA was significantly higher than in the nonhandled group. The reduced secretion of E2, LH, FSH and LHRH on the proestrus day may explain the anovulatory estrous cycle in neonatal handled rats. The reduced secretion of PRL in the proestrus may be related to the decreased sexual receptiveness in handled females. In conclusion, early-life environmental stimulation can induce long-lasting effects on the hypothalamus-pituitary-gonad axis.

Splitting of the locomotor activity rhythm in rats by exposure to continuous light

1983 ◽  
Vol 244 (4) ◽  
pp. R573-R576 ◽  
Author(s):  
Phyllis W. Cheung ◽  
Charles E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Estrous Cycle ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Female Rats ◽  
Locomotor Rhythm ◽  
Estrous Cycles ◽  
Locomotor Activity Rhythm ◽  
Active Portion ◽  
Free Running

Female rats exposed to low intensities (0.1–1.5 lx) of continuous light (LL), displayed regular estrous cycles and free-running circadian rhythms of locomotor activity. In most rats, as the intensity of LL was increased to >2.0 lx, components within the active portion (α) of the locomotor rhythm remained synchronized as the periodicity of the rhythm lengthened. However, in a few rats agr split into two components; one of which free-ran with a period shorter than 24 h, while the other free-ran with a period longer than 24 h. As soon as the two components became maximally separated they spontaneously rejoined. In most rats, estrous cycles ceased shortly after the intensity of LL was increased to >2.0 lx even though the locomotor activity rhythm retained its unsplit free-running nature. These observations suggest that the multiple oscillators that control the rhythms of locomotor activity and the estrous cycle are normally coupled to one another. In certain intensities of LL, these oscillators uncouple and free-run with different periodicities, a condition which causes estrous cycles to cease and sometimes produces a split locomotor activity rhythm. circadian rhythm; oscillators; estrous cycle Submitted on November 9, 1981 Accepted on October 11, 1982

Evidence for a role for the neurosteroid allopregnanolone in the modulation of reproductive function in female rats

1995 ◽  
Vol 133 (3) ◽  
pp. 375-380 ◽  
Author(s):  
Andrea R Genazzani ◽  
Marco A Palumbo ◽  
Antonio A de Micheroux ◽  
Paolo G Artini ◽  
Mario Criscuolo ◽  
...  
Keyword(s):  
Sexual Behavior ◽  
Liquid Chromatography ◽  
Estrous Cycle ◽  
Brain Cortex ◽  
Reproductive Function ◽  
Ovulation Rate ◽  
Female Rats ◽  
Obstetrics And Gynecology ◽  
Intracerebroventricular Injection ◽  
Medial Basal Hypothalamus

Genazzani AR, Palumbo MA, de Micheroux AA, Artini PG, Criscuolo M, Ficarra G, Guo A-L, Benelli A, Bertolini A, Petraglia E. Purdy RH. Evidence for a role for the neurosteroid allopregnanolone in the modulation of reproductive function in female rats. Eur J Endocrinol 1995;133:375–80. ISSN 0804–4643 The present study investigated the effect of allopregnanolone (5α-pregnan-3α-ol-20-one) or of passive immunoneutralization of brain allopregnanolone, the most potent steroid produced by neurons, on ovulation rate and sexual behavior in female rats. Allopregnanolone was injected intracerebroventricularly in rats on diestrus and proestrus and tests were done on estrus. The intracerebroventricular injection of allopregnanolone significantly decreased the number of oocytes collected on estrus (p < 0.01). To support a physiological involvement, antiserum to allopregnanolone was injected centrally to block the activity of the endogenous neurosteroid. When administered on diestrus and proestrus or only on proestrus, the antiserum was shown to be correlated with a significant increase (p < 0.01) in oocytes retrieved on estrus. In female rats treated with antiserum to allopregnanolone, the lordosis intensity was augmented significantly as compared to controls. Finally, the possible changes of medial basal hypothalamus concentration of allopregnanolone throughout the estrous cycle and at the time of ovulation were investigated. Hypothalamic extracts were eluted on highpressure liquid chromatography and allopregnanolone concentration was measured by radioimmunoassay. Brain cortex was used as control tissue. Hypothalamic allopregnanolone concentration on proestrus morning and afternoon was found to be significantly lower than in the remaining phases of the estrous cycle (p < 0.01), while no significant changes were observed in brain cortex concentration of allopregnanolone. The present results suggest that hypothalamic allopregnanolone may be involved in the mechanism of ovulation, affecting hormonal and behavioral events. AR Genazzani, Institute of Obstetrics and Gynecology, University of Pisa, via Roma 67, 56100 Pisa, Italy

scholarly journals Effect of Penicillin on Reproductive Function in Female Wistar Rats

2021 ◽  
Vol 71 (2) ◽  
Author(s):  
Oyedeji K.O ◽  
Momoh R.O ◽  
Oderinde Gbenga
Keyword(s):  
Estrous Cycle ◽  
Wistar Rats ◽  
Reproductive Function ◽  
Daily Basis ◽  
Female Rats ◽  
Histopathological Study ◽  
Fertility Effect ◽  
Female Wistar Rats ◽  
Student’S T ◽  
Histopathological Studies

This study was designed to investigate the effect of penicillin on reproductive function in female Wistar rats. Fifteen female rats (120 – 160 g) were used for the estrous cycle and histopathological studies. Penicillin (17.14 mg/kg) was administered orally on daily basis for 21 and 50 days respectively for the estrous cycle and histological studies. Estrous cycle was carried out using the technique of Marcondes et al., histologies of the ovaries and uteri were also carried out. Data were analysed using descriptive statistics and student’s t-test at p=0.05. Treatment of rats for 21 days with penicillin (17.14 mg/kg) produced significant (p<0.05) increments in the estrous and metestrous phases as well as a significant (p<0.05) reduction in the proestrous phase of the estrous cycle relative to their respective controls. The histopathological study presented with a moderate endometrial congestion. It can therefore be concluded that penicillin probably has a pro-fertility effect with a moderate deleterious effect on the uteri at histological level in female Wistar rats.

scholarly journals Immunotoxic Destruction of Distinct Catecholaminergic Neuron Populations Disrupts the Reproductive Response to Glucoprivation in Female Rats

Endocrinology ◽  
2003 ◽  
Vol 144 (10) ◽  
pp. 4325-4331 ◽  
Author(s):  
Helen I’Anson ◽  
Lois A. Sundling ◽  
Shannon M. Roland ◽  
Sue Ritter
Keyword(s):  
Cycle Length ◽  
Reproductive Function ◽  
Female Rats ◽  
Estrous Cycles ◽  
Neuron Populations ◽  
Reproductive Response ◽  
Estrous Cyclicity ◽  
Catecholaminergic Neuron ◽  
Catecholamine Neurons ◽  
Glucoprivic Feeding

We tested the hypothesis that hindbrain catecholamine (norepinephrine or epinephrine) neurons, in addition to their essential role in glucoprivic feeding, are responsible for suppressing estrous cycles during chronic glucoprivation. Normally cycling female rats were given bilateral injections of the retrogradely transported ribosomal toxin, saporin, conjugated to monoclonal dopamine β-hydroxylase antibody (DSAP) into the paraventricular nucleus (PVN) of the hypothalamus to selectively destroy norepinephrine and epinephrine neurons projecting to the PVN. Controls were injected with unconjugated saporin. After recovery, we assessed the lesion effects on estrous cyclicity under basal conditions and found that DSAP did not alter estrous cycle length. Subsequently, we examined effects of chronic 2-deoxy-d-glucose-induced glucoprivation on cycle length. After two normal 4- to 5-d cycles, rats were injected with 2-deoxy-d-glucose (200 mg/kg every 6 h for 72 h) beginning 24 h after detection of estrus. Chronic glucoprivation increased cycle length in seven of eight unconjugated saporin rats but in only one of eight DSAP rats. Immunohistochemical results confirmed loss of dopamine β-hydroxylase immunoreactivity in PVN. Thus, hindbrain catecholamine neurons with projections to the PVN are required for inhibition of reproductive function during chronic glucose deficit but are not required for normal estrous cyclicity when metabolic fuels are in abundance.

Periodic, short-term heat exposure and reproductive function in male and female rats

1978 ◽  
Vol 56 (5) ◽  
pp. 747-753 ◽  
Author(s):  
Edwin A. Knecht ◽  
Gary L. Wright ◽  
Mark A. Toraason
Keyword(s):  
Heat Treatment ◽  
Heat Exposure ◽  
Reproductive Function ◽  
Female Rats ◽  
Short Term ◽  
Estrous Cycles ◽  
Male And Female ◽  
Fetal Survival ◽  
Male And Female Rats ◽  
High Incidence

Reproductive function of male and female rats was examined in relation to periodic, short-term heat treatment. Daily exposure to an environmental temperature of 38.2 °C for 55 min elevated rectal temperatures to 39.9 and 41.2 °C in male and female rats, respectively. Heat exposure tended to decrease copulation in males cohabitated with unhealed females. The rate of conception was affected similarly, and fetal survival tended to be reduced by paternal heat treatment. Estrous cycles were disrupted initially in heat-exposed females, but the rate of copulation and conception of females cohabitated with unheated males was unaltered by heat treatment. However, maternal heat exposure impaired prenatal survival and growth. During lactation, a high incidence of maternal and pup deaths was observed at approximately 14 days postpartum. Maternal deaths were coincident with a decrease in thermoregulatory ability and rectal temperatures exceeding 42 °C.

scholarly journals Effect of Immune and Metabolic Challenges on the Luteinizing Hormone-Releasing Hormone Neuronal System in Cycling Female Rats: An Evaluation at the Transcriptional Level*

Endocrinology ◽  
1997 ◽  
Vol 138 (4) ◽  
pp. 1374-1384 ◽  
Author(s):  
Rossella E. Nappi ◽  
Serge Rivest
Keyword(s):  
Gene Expression ◽  
In Situ Hybridization ◽  
Estrous Cycle ◽  
Neuronal Activity ◽  
Anterior Pituitary ◽  
Preoptic Area ◽  
Female Rats ◽  
Lamina Terminalis ◽  
Ovulatory Cycle

Abstract The purpose of this study was to investigate the influence of immune (systemic endotoxin administration) and metabolic (fasting) challenges on LHRH neuronal activity and transcription in the organum vasculosum of the lamina terminalis/medial preoptic area as well as on the expression of the LHRH receptor (LHRH-R) in the anterior pituitary of cycling female rats. The reproductive stages of adult female rats (200–250 g; 14 h of light; lights on at 0600 h) were verified by daily vaginal smears taken every morning for a minimum of three or four cycles before the experiment. The acute-phase response was induced via an ip injection of lipopolysaccharide (LPS; 200μ g/100 g BW), whereas the metabolic challenge consisted of food deprivation for at least 48 h. Control and challenged rats were killed at specific times in the ovulatory cycle (1200, 1500, and 1800 h on proestrus and diestrous day 2). Frozen brains and pituitaries were mounted on a microtome, cut into 30-μm slices, and then processed for the detection of transcripts encoding either LHRH or LHRH-R by means of in situ hybridization histochemistry using intronic (heteronuclear RNA) and exonic [messenger RNA (mRNA)] riboprobes. Dual immunocytochemistry to detect Fos-immunoreactive (ir) nuclei in LHRH-ir perikarya and colocalization of LHRH mRNA with Fos protein during the day of proestrus were performed by using both in situ hybridization and immunocytochemistry techniques on the same brain sections. The percentage of LHRH-ir and LHRH-expressing neurons displaying positive Fos-ir nuclei during the afternoon of proestrus was significantly inhibited 3 h after endotoxin administration. Rats exhibited an increase in the levels of LHRH primary transcript in the organum vasculosum of the lamina terminalis/medial preoptic area structure at 1500 h on proestrus, a phenomenon significantly attenuated by LPS injection only at this phase of the estrous cycle. On the other hand, fasting did not affect LHRH neuronal activity or gene expression in intact cycling rats, but affected these cells in animals exhibiting a disruption of the ovulatory cycle. Interestingly, LPS caused a profound down-regulation of LHRH-R gene expression in the anterior pituitary throughout the entire estrous cycle. Although food deprivation provoked a more variable pattern of LHRH-R mRNA in cycling rats, the signal for this transcript in the adenohypophysis was deeply altered in those showing a perturbed cycle. These results provide evidence that immune challenge interferes with the LHRH system at both hypothalamic and pituitary levels, whereas alteration of that neuroendocrine system in food-deprived rats seems highly associated with the impairment of reproductive cyclicity.

scholarly journals Changes in α-estradiol receptor and progesterone receptor expression in the locus coeruleus and preoptic area throughout the rat estrous cycle

2006 ◽  
Vol 188 (2) ◽  
pp. 155-165 ◽  
Author(s):  
Cleyde Vanessa Vega Helena ◽  
Maristela de Oliveira Poletini ◽  
Gilberto Luiz Sanvitto ◽  
Shinji Hayashi ◽  
Celso Rodrigues Franci ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Locus Coeruleus ◽  
Estrous Cycle ◽  
Preoptic Area ◽  
Receptor Expression ◽  
Female Rats ◽  
Control Mechanisms ◽  
Estradiol Receptor ◽  
Estradiol Levels ◽  
Lower Expression

We have previously shown that the locus coeruleus (LC) is essential for triggering surges of LH. Since LC neurons are responsive to estradiol, which induces progesterone receptor (PR) expression, this study aimed to investigate whether LC neurons express the α-estradiol receptor (αER) and PR as well as comparing such responses to that observed in the preoptic area (POA). Female rats were perfused at 10, 14 and 16 h on each day of the estrous cycle, and a blood sample was collected for estradiol, progesterone and LH measurements. αER- and PR immunoreactive (ir) neurons were detected in POA and LC by immunocytochemistry (ICC). Higher plasma estradiol levels were observed on the day of proestrus, when a smaller number of αER-ir POA neurons were detected. An increase in the number of αER-ir neurons were observed at 16 h of proestrus and estrus. The number of PR-ir neurons increased in POA only at 16 h of proestrus, and remained unchanged during all other days and times. The profile of αER-ir and PR-ir neurons in LC changed over the estrous cycle, with a lower expression on metestrus morning and reaching a peak on diestrus afternoon before declining on the day of proestrus. However, on estrus afternoon, αER-ir neurons increased, while PR-ir neurons decreased which may be related to the prolactin surge of estrus. These data show that LC neurons express αER and PR and seem to be more sensitive to variations in estradiol than POA. Also, the fluctuation in αER and PR observed for LC neurons seems to accompany the hormonal events that occur during the estrous cycle. This profile of αER and PR expression might be related to the ability of estradiol and progesterone in regulating the activity of LC neurons, which could be associated to the control mechanisms of LH and prolactin release.

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