Biology of Reproduction Research Unit

Juchitán de Zaragoza, Mexico

Biology of Reproduction Research Unit

Juchitán de Zaragoza, Mexico

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PubMed | Biology of Reproduction Research Unit, National Institute of Geriatrics and Instituto Nacional Of Ciencias Medicas Y Nutricion Salvador Zubiran
Type: Journal Article | Journal: Reproductive biology and endocrinology : RB&E | Year: 2016

Muscarinic receptors (mAChRs) of the preoptic and anterior hypothalamus areas (POA-AHA) regulate ovulation in an asymmetric manner during the estrous cycle. The aims of the present study were to analyze the effects of a temporal blockade of mAChRs on either side of the POA-AHA performed in diestrus-2 rats on ovulation, the levels of estradiol, follicle stimulating hormone (FSH) and luteinizing hormone (LH) and the mechanisms involved in changes in ovulation.Cyclic rats on diestrus-2day were anesthetized and randomly assigned to the following groups: 1) microinjection of 1l of saline or atropine solution (62.5ng) in the left or right POA-AHA; 2) removal (unilateral ovariectomty, ULO) of the left (L-ULO) or right (R-ULO) ovary, and 3) rats microinjected with atropine into the left or right POA-AHA plus L-ULO or R-ULO. The ovulation rate and the number of ova shed were measured during the predicted estrus, as well as the levels of estradiol, FSH and LH during the predicted proestrus and the effects of injecting synthetic LH-releasing hormone (LHRH) or estradiol benzoate (EB).Atropine in the left POA-AHA decreased both the ovulation rate and estradiol and LH levels on the afternoon of proestrus, also LHRH or EB injection restored ovulation. L- or R-ULO resulted in a lower ovulation rate and smaller number of ova shed, and only injection of LHRH restored ovulation. EB injection at diestrus-2 restored ovulation in animals with L-ULO only. The levels of estradiol, FSH and LH in rats with L-ULO were higher than in animals with unilateral laparotomy. In the group microinjected with atropine in the left POA-AHA, ovulation was similar to that in ULO rats. In contrast, atropine in the right POA-AHA of ULO rats blocked ovulation, an action that was restored by either LHRH or EB injection.These results indicated that the removal of a single ovary at noon on diestrus-2day perturbed the neuronal pathways regulating LH secretion, which was mediated by the muscarinic system connecting the right POA-AHA and the ovaries.


Linares R.,Biology of Reproduction Research Unit | Hernandez D.,Biology of Reproduction Research Unit | Moran C.,Autonomous University of Puebla | Chavira R.,Institute Nacional Of Ciencias Medicas Y Nutricion Salvador Zubiran | And 3 more authors.
Reproductive Biology and Endocrinology | Year: 2013

Background: Injecting estradiol valerate (EV) to pre-pubertal or adult female rat results in effects similar to those observed in women with polycystic ovarian syndrome (PCOS). One of the mechanisms involved in PCOS development is the hyperactivity of the sympathetic nervous system. In EV-induced PCOS rats, the unilateral sectioning of the superior ovarian nerve (SON) restores ovulation of the innervated ovary. This suggests that, in addition to the sympathetic innervation, other neural mechanisms are involved in the development/maintenance of PCOS. The aims of present study were analyze if the vagus nerve is one of the neural pathways participating in PCOS development.Methods: Ten-day old rats were injected with EV dissolved in corn oil. At 24-days of age sham-surgery, unilateral, or bilateral sectioning of the vagus nerve (vagotomy) was performed on these rats. The animals were sacrificed at 90-92 days of age, when they presented vaginal estrous preceded by a pro-estrus smear.Results: In EV-induced PCOS rats, unilateral or bilateral vagotomy restored ovulation in both ovaries. Follicle-stimulating hormone (FSH) levels in PCOS rats with unilateral or bilateral vagotomy were lower than in control rats.Conclusions: This result suggests that in EV-induced PCOS rats the vagus nerve is a neural pathway participating in maintaining PCOS. The vagus nerve innervates the ovaries directly and indirectly through its synapsis in the celiac-superior-mesenteric ganglion, where the somas of neurons originating in the SON are located. Then, it is possible that vagotomy effects in EV-induced PCOS rats may be explained as a lack of communication between the central nervous system and the ovaries. © 2013 Linares et al.; licensee BioMed Central Ltd.


Morales-Ledesma L.,Biology of Reproduction Research Unit | Ramirez D.A.,Biology of Reproduction Research Unit | Vieyra E.,Biology of Reproduction Research Unit | Trujillo A.,Autonomous University of Puebla | And 3 more authors.
Reproductive Biology and Endocrinology | Year: 2011

In the present study we analyzed the existence of asymmetry in the secretion of steroid hormones in pre-pubertal female rats treated with unilateral ovariectomy (ULO) or unilateral perforation of the abdominal wall (sham-surgery). Treated rats were sacrificed at different times after surgery. Since sham-surgery had an apparent effect on the age of first vaginal estrous (FVE) and serum levels hormone, the results of the sham surgery groups were used to assess the effects of their respective surgery treatment groups. On the day of FVE, compensatory ovulation (CO) and compensatory ovarian hypertrophy (COH) were similar in animals with ULO, regardless of the ovary remaining in situ. In ULO treated animals, progesterone (P4) levels were higher than in animals with sham-surgery one hour after treatment but lower in rats sacrificed at FEV. Left-ULO resulted in lower testosterone (T) concentration 48 and 72 hours after surgery. In rats with Right-ULO lower T concentrations were observed in rats sacrificed one or 72 hours after surgery, and at FVE. ULO (left or right) resulted in lower estradiol (E2) concentrations one or 72 hours after treatment. In rats with Left-ULO, E2 levels were higher 48 hours after surgery and at FVE. Left-ULO resulted in higher levels of follicle stimulating hormone (FSH) five hours after surgery and at FVE. FSH levels were higher in rats with Right-ULO sacrificed on FVE. The present results suggest that in the pre-pubertal rat both ovaries have similar capacities to secrete P4, and that the right ovary has a higher capacity to secrete E2. Taken together, the present results support the idea that the effects of ULO result from the decrease in glandular tissue and changes in the neural information arising from the ovary. © 2011 Morales-Ledesma et al; licensee BioMed Central Ltd.


Rosas G.,Biology of Reproduction Research Unit | Ramirez M.I.,Biology of Reproduction Research Unit | Linares R.,Biology of Reproduction Research Unit | Trujillo A.,Autonomous University of Puebla | And 2 more authors.
Endocrine | Year: 2015

In vitro the vasoactive intestinal peptide (VIP) stimulates progesterone, androgens, and estradiol secretion, and the effects are time-dependent. The present study analyzed the acute (1 h) and sub-acute (24 h) effects of unilateral injection of VIP into the ovarian bursa on each day of the estrous cycle on progesterone, testosterone, and estradiol serum levels. Cyclic 60-day-old virgin female rats on diestrus-1, diestrus-2, proestrus, or estrus were injected with saline or VIP 10−6 M into the left or right ovarian bursa. One hour after saline injection on each day of estrus cycle, progesterone levels were higher than in control animals. The acute effects of saline solution on testosterone and estradiol levels were asymmetric and varied during the estrous cycle. In comparison with saline groups, the effects of VIPergic stimulation on progesterone, testosterone, and estradiol serum levels depend on the time elapsed between treatment and autopsy and vary during the estrous cycle. An acute asymmetric response from the ovaries to the VIP was observed at diestrus-1, diestrus-2, and proestrus on progesterone and estradiol levels. The asymmetries on testosterone levels were observed at diestrus-1, diestrus-2, and estrus days. The present results suggest that in the cyclic rat, each ovary has different sensitivities to VIPergic stimulation which depends on the endocrine status of the animal. © 2014, Springer Science+Business Media New York.


PubMed | Biology of Reproduction Research Unit, Autonomous University of Puebla, Metropolitan Autonomous University and Instituto Nacional Of Ciencias Medicas Y Nutricion Salvador Zubiran
Type: Journal Article | Journal: Reproductive biology and endocrinology : RB&E | Year: 2016

The suprachiasmatic nucleus (SCN) and the cholinergic system of various regions of the hypothalamus participate in the regulation of gonadotropin-releasing hormone (GnRH) and gonadotropin secretion, which are necessary for the occurrence of ovulation. In the present study, our goal was to analyse the effects of unilaterally blocking the muscarinic receptors in the SCN on ovulation and steroid secretion.Cyclic rats were randomly allotted to one of the experimental groups. Groups of 8-14 rats were anaesthetized and microinjected with 0.3l of saline or a solution of atropine (62.5ng in 0.3l of saline) into the left or right SCN at 09.00 or 19.00h during diestrus-1 or on the proestrus day. The rats were euthanized on the predicted day of oestrus, and evaluated ovulation and levels of progesterone and oestradiol. Other groups of 10 rats were microinjected with atropine into the left or right SCNs at 09.00h on the proestrus day, were euthanized eight h later, and luteinizing hormone (LH) was measured.At 09.00 or 19.00h during diestrus-1, atropine microinjections into the SCNs on either side did not modify ovulation. The atropine microinjections performed at 09.00h of proestrus into either side of the SCN blocked ovulation (right SCN: 1/9 ovulated vs. 9/10 in the saline group; left SCN: 8/14 ovulated vs. 10/10 in the saline group). The LH levels at 17.00h in the rats that were microinjected with atropine at 09.00h of proestrus were lower than those of the controls. In the non-ovulating atropine-treated rats, the injection of synthetic LH-releasing hormone (LHRH) restored ovulation. Atropine treatment at 19.00h of proestrus on either side of the SCN did not modify ovulation, while the progesterone and oestradiol levels were lower.Based on the present results, we suggest that the cholinergic neural information arriving on either side of the SCN is necessary for the pre-ovulatory secretion of LH to induce ovulation. Additionally, the regulation of progesterone and oestradiol secretion by the cholinergic innervation of the SCN varies with the time of day, the day of the cycle, and the affected SCN.


PubMed | Biology of Reproduction Research Unit and Autonomous University of Puebla
Type: | Journal: Reproductive biology and endocrinology : RB&E | Year: 2015

The present study investigates sectioning the superior ovarian nerve (SON) in rats with functional sensorial denervation induced by capsaicin administration at birth and the effects on the establishment of puberty, ovulation, serum progesterone, and estradiol concentrations.The animals were allotted randomly to one of the following experimental groups. Groups of 8-10 rats were injected at birth with capsaicin or vehicle, and on day 20 or 28 of life, they were submitted to a sham operation (SO). Other groups of 8-10 rats were injected at birth with capsaicin or vehicle, and on day 20 or 28 of life, they were submitted to the uni-or bilateral SON sectioning. The animals were killed at the first estrus. Serum concentration of progesterone (ng/ml) and estradiol (pg/ml) were measured using a radioimmunoassay.Animals treated with capsaicin and subjected at 20days of life to the left or bilateral section of SON had a delayed age of vaginal opening. Furthermore, animals with a lack of sensory information and subjected to a SO at 28days of life had the same delay in the age of vaginal opening. Animals with sensorial innervation intact, subjected to unilateral section of the SON at 20 or 28days of age, showed diminished ovulation rate and number of ova shed by the denervated ovary. In animals with sensorial denervation, the uni-or bilateral sectioning of the SON did not result in changes in ovulation. Progesterone and estradiol levels were different depending on the age of the animal in which the SON section was performed.Based on the present results, we suggest that sympathetic innervation regulates ovulation and the secretion of steroid hormones and that the sensory fibers modulate the sympathetic innervation action on ovarian functions.


Cruz M.E.,Biology of Reproduction Research Unit | Olvera E.,Biology of Reproduction Research Unit | Perez M.J.,Biology of Reproduction Research Unit | Min E.I.,Biology of Reproduction Research Unit | And 4 more authors.
Alcoholism: Clinical and Experimental Research | Year: 2014

Background: Intragastric or intraperitoneal ethanol (EtOH) treatment inhibits reproductive functions in females and male rats. The area of the hypothalamus where these effects take place is unknown. As the participations of the preoptic-anterior hypothalamic area (POA-AHA) in regulating ovulation is asymmetric, this study aims to analyze the effects on 17β-estradiol(E2), progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) serum levels, the messenger ribonucleic acid (mRNA) expression of estrogen receptor alpha (ERα) and beta (ERβ), and ovulation resulting from unilaterally microinjecting water or an EtOH solution into either side of the POA-AHA. Methods: The treatment consisted of microinjecting a 8.6 μM EtOH solution into either side of the POA-AHA. The study was performed on groups of adult cyclic rats at 09.00 hours on diestrus-1, and sacrificed on diestrus-2 at 13.00, on proestrus at 09.00 or 17.00 or on estrus at 09.00 hours. Ovulation rates were assessed in rats sacrificed on estrus. Hormonal serum levels were measured using radioimmunoassay, and as a function of ERα and ERβ mRNA expression in each side of the POA-AHA by reverse transcriptase polymerase chain reaction. Results: EtOH treatment blocked ovulation and the preovulatory release of LH, and lowered E2 levels. Irrespective of the treated POA-AHA side, ERα mRNA expression was consistently lower in the left POA-AHA and higher on the right. EtOH treatment in the left POA-AHA decreased FSH serum levels and lowered ERβ mRNA expression. In turn, EtOH treatment on the right POA-AHA resulted in higher FSH levels and ERβ mRNA expression. Conclusions: The present results show that EtOH blocks the preovulatory surge of LH on the POA-AHA. The effects of EtOH treatment of preovulatory FSH surge on the POA-AHA are asymmetric (stimulative on the right and inhibiting in the left). The effects of EtOH treatment on preovulatory LH and FSH surge could be explained by the inhibition of ERα and ERβ mRNA expression, respectively. © 2014 by the Research Society on Alcoholism.


Cruz M.E.,Biology of Reproduction Research Unit | Flores A.,Biology of Reproduction Research Unit | Dominguez R.,Biology of Reproduction Research Unit
Endocrine | Year: 2014

Atropine implants in the preoptic-anterior hypothalamic areas (POA-AHA) block ovulation. The blocking effects depend on the side of POA-AHA and the day of the estrous cycle in which the implants are inserted. Since ovulation is the result of the growth and differentiation of ovarian follicles, the purpose of this study was to analyze the changes in follicular and atresia population in the ovaries of non-ovulating rats resulting from the unilateral atropine implants in the POA-AHA. Groups of cyclic rats were implanted with atropine or cholesterol (sham treatment group) in the left (diestrus-1, diestrus-2) or the right side (estrus, diestrus-1) of the POA-AHA. The animals were sacrificed on the expected proestrus or estrus day, and the follicular population was counted and the follicles measured in both ovaries. Atropine implants inserted in the left POA-AHA on diestrus-2 resulted in lower follicular growth and atresia in the ipsilateral ovary (left one). No apparent effects were observed in the right ovary. Atropine implants inserted in the right POA-AHA on estrus day resulted in fewer numbers of small follicles in the ipsilateral ovary (right) and a greater number of pre-ovulatory ones. Present results suggest that acetylcholine, via muscarinic receptors of the POA-AHA, regulates ovarian follicular fate in an asymmetric way, and that its actions fluctuate during the estrous cycle. In addition, each ovary seems to respond differently to the POA-AHA’s muscarinic signal surge on estrus and diestrus-2 days. © 2014, Springer Science+Business Media New York.


PubMed | Biology of Reproduction Research Unit
Type: Journal Article | Journal: Endocrine | Year: 2015

In vitro the vasoactive intestinal peptide (VIP) stimulates progesterone, androgens, and estradiol secretion, and the effects are time-dependent. The present study analyzed the acute (1h) and sub-acute (24h) effects of unilateral injection of VIP into the ovarian bursa on each day of the estrous cycle on progesterone, testosterone, and estradiol serum levels. Cyclic 60-day-old virgin female rats on diestrus-1, diestrus-2, proestrus, or estrus were injected with saline or VIP 10(-6) M into the left or right ovarian bursa. One hour after saline injection on each day of estrus cycle, progesterone levels were higher than in control animals. The acute effects of saline solution on testosterone and estradiol levels were asymmetric and varied during the estrous cycle. In comparison with saline groups, the effects of VIPergic stimulation on progesterone, testosterone, and estradiol serum levels depend on the time elapsed between treatment and autopsy and vary during the estrous cycle. An acute asymmetric response from the ovaries to the VIP was observed at diestrus-1, diestrus-2, and proestrus on progesterone and estradiol levels. The asymmetries on testosterone levels were observed at diestrus-1, diestrus-2, and estrus days. The present results suggest that in the cyclic rat, each ovary has different sensitivities to VIPergic stimulation which depends on the endocrine status of the animal.

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