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Although in recent times there has been an interest in deepening the relationship between nocturnal temporality and the diversified experiences of metropolitan spaces, in Mexico, little research has been carried out on the experience of night in the public spaces that we inhabit on a daily basis. We propose to analyze the role that women play in the nighttime public space, providing elements to deconstruct the opposition between the public and the private sphere. Our field of study is the shopping street of the popular neighborhood of Santo Domingo (CDMX) where we carried out fieldwork sessions with different research methods (semi-structured interviews, ethnographic observation, semi-structured interviews, and a survey). The first results of our analysis show how the presence of women in this street during night hours impacts environments in which elements from the realms of the public and private spheres and community (Lofland, 1989) interact. This space-time is taken over by women, thus contributing to the perception of the shopping street as an accessible and diversified public space at night. Aunque en tiempos recientes ha crecido el interés por profundizar la relación entre la temporalidad nocturna y las experiencias diversificadas de los espacios metropolitanos, en México, poco se ha reflexionado sobre la experiencia de la noche en los espacios públicos que cotidianamente habitamos. Proponemos analizar el rol que las mujeres juegan en el espacio público nocturno, aportando elementos para deconstruir la oposición entre lo público y lo privado. Nuestro terreno de estudio es la calle comercial de la colonia popular de Santo Domingo (CDMX) donde realizamos sesiones de trabajo de campo aplicando diferentes métodos de investigación (entrevistas semi-estructuradas, observación etnográfica, una encuesta). Los primeros resultados del análisis, evidencian como la presencia de las mujeres durante horarios nocturnos configura ámbitos donde elementos de los reinos de lo público, privado y comunitario (Lofland, 1989) interactuando, se mezclan. Dicho espacio-tiempo apropiado por las mujeres contribuye en la percepción de la calle comercial como un espacio público accesible y diversificado en el horario nocturno. Palabras clave: mujer, espacio público, noche, México Peer Reviewed Objectius de Desenvolupament Sostenible::5 - Igualtat de Gènere

The research is a study of two cases and have been used 15 in-depth interviews made to the social workers of different mental health services in Messina and Agrigento. Research is moving along a path of inductive and exploratory. It has tried understanding the characteristics of the social worker’s job. They were examined by public psychiatric services of the Departments of Mental Health of Messina and Agrigento. The aim of this paper is to reflect on the close relationship between social workers and other professionals in the mental health care of public facilities, such as psychiatrists. The intention is to respond to the need to examine the interaction of this professional group and better understand the different path by which you can keep autonomy and/or negotiate professional position, especially in relation to other professions medical sector. We have chosen to focus on the social worker’s role in psychiatry because it is the key figure of the present socio-health integration process. This has given rise to numerous challenges related to building and strengthening its social identity-professional.

El impulso del modelo económico neoliberal en la Ciudad de México ha estimulado la inversión de capital en obras e intervenciones, las cuales desencadenan problemas entre los actores sociales involucrados. El siguiente artículo propone un análisis del conflicto en torno al carácter público del parque Reforma Social, ubicado en la alcaldía Miguel Hidalgo, en el que asistimos al enfrentamiento de intereses entre los vecinos —movilizados para conservar el parque— y un grupo de actores que tiene planeado desarrollar un proyecto inmobiliario. En el marco de las pugnas territoriales que atraviesan esta metrópolis, analizamos la controversia bajo el supuesto de que esta modifica las relaciones de poder previas al estallido de la confrontación y tiene una productividad. Después de delimitar el conflicto como situación, se recupera la voz de los actores, sus argumentos y posicionamientos, desde una lectura que analiza las alianzas, así como la capacidad de los vecinos de proponer nuevas estrategias de defensa territorial. Dentro de los resultados, se evidencia cómo al mismo tiempo que se incrementa la cohesión de los residentes, se reconoce el papel protagónico desempeñado por la cartografía, en particular, en lo que concierne al proceso de apropiación y de proyección territorial experimentado por los vecinos de la colonia.

Calcium sulfate bone void fillers are increasingly being used for dead space management in infected arthroplasty revision surgery. The presence of these materials as loose beads close to the bearing surfaces of joint replacements gives the potential for them to enter the joint becoming trapped between the articulating surfaces; the resulting damage to cobalt chrome counterfaces and the subsequent wear of ultra-high-molecular-weight polyethylene is unknown. In this study, third-body damage to cobalt chrome counterfaces was simulated using particles of the calcium sulfate bone void fillers Stimulan®(Biocomposites Ltd., Keele, UK) and Osteoset®(Wright Medical Technology, TN, USA) using a bespoke rig. Scratches on the cobalt chrome plates were quantified in terms of their density and mean lip height, and the damage caused by the bone void fillers was compared to that caused by particles of SmartSet GMV PMMA bone cement (DePuy Synthes, IN, USA). The surface damage from Stimulan®was below the resolution of the analysis technique used; SmartSet GMV caused 0.19 scratches/mm with a mean lip height of 0.03 µm; Osteoset®led to a significantly higher number (1.62 scratches/mm) of scratches with a higher mean lip height (0.04 µm). Wear tests of ultra-high-molecular-weight polyethylene were carried out in a six-station multi-axial pin on plate reciprocating rig against the damaged plates and compared to negative (highly polished) and positive control plates damaged with a diamond stylus (2 µm lip height). The wear of ultra-high-molecular-weight polyethylene was shown to be similar against the negative control plates and those damaged with third-body particles; there was a significantly higher ( p

Il diritto alla salute fa parte dei diritti universalmente riconosciuti e garantiti ad ogni individuo, indipendentemente dal possedimento o meno dello status di cittadino. Avere accesso alle cure quando e necessario e un modo per gli stranieri di far valere questo diritto e di mantenere il loro stato di salute. Dagli ultimi dati Istat e del Ministero della Salute risulta che la popolazione straniera cinese si caratterizza per un tasso di ospedalizzazione significativamente piu basso rispetto ad altre comunita di stranieri. Questa ricerca si concentra sull’analisi della modalita di accesso ai servizi sanitari da parte della popolazione cinese di Messina. Le caratteristiche della comunita di indagine, hanno portato a privilegiare strumenti di analisi di tipo quantitativo. Sono stati somministrati 130 questionari a risposta chiusa. I primi risultati che emergono dalla ricerca sono: l’orientamento diffuso tra i cinesi di fare un uso differenziato della medicina tradizionale e di quella occidentale; il diffidare dei servizi sanitari locali perche costretti ad affrontare diversi ostacoli linguistici e logistici.

Ceramic composites have performed very well under adverse edge loading conditions when used in like-on-like configurations, where the femoral head and acetabular cup are of the same material. The aim of this study was to determine the wear of pure alumina (Al2 O3 ), alumina toughened zirconia (ATZ) and zirconia toughened alumina (ZTA) when used in mixed bearing combinations, under edge loading conditions due to translational mal-positioning. The head-on-cup configurations of three ceramic materials were ATZ-on-ZTA, ZTA-on-ATZ, Al2 O3 -on-ATZ, ATZ-on-Al2 O3 , Al2 O3 -on-ZTA, and ZTA-on-Al2 O3 . They were tested on the Leeds II hip simulator under microseparation conditions. The bedding in and steady state wear rates of ATZ-on-ZTA were 1.16mm3 /million cycles and 0.18mm3 /million, respectively, and for ATZ-on-Al2 O3 were 0.66 mm3 /million cycles and 0.20 mm3 /million, respectively. The wear rates of the other bearing combinations under these adverse microseparation conditions, Al2 O3 -on-ATZ, Al2 O3 -on-ZTA, ZTA-on-ATZ and ZTA-on-Al2 O3 were very low with no clear bedding in and steady state phases, and with steady state wear rates lower than 0.11 mm3 /million. The mixed material combinations tested in this study have shown slightly higher wear rates when compared to ATZ in like-on-like configuration reported previously, but superior wear resistance when compared to alumina-on-alumina bearings tested previously under the same adverse microseparation conditions. © 2016 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1361-1368, 2017.

The endocrine disruptor di-(2-ethylhexyl) phthalate (DEHP) is used in a variety of consumer products made with polyvinyl chloride and also in the manufacture of medical devices. DEHP disrupts reproductive tract development in an antiandrogenic manner and also may induce neurobehavioral changes. The aim of this study was to investigate the effects of chronic postnatal exposure to DEHP (30 mg/kg body weight/day, orally from birth to day 60) on the neuroendocrine regulation of the gonadal axis and its impact on the anxiety-like behavior in adult male rats, as well as the probable participation of the GABAergic system in these effects. DEHP produced a significant increase in plasmatic luteinizing hormone and follicle stimulating hormone, as well as significant testosterone decrease, accompanied with a decrease in hypothalamic gamma-aminobutyric acid (GABA) concentration. On the other hand, DEHP increased the anxiety-like behavior in the elevated plus maze test, evidenced by a significant decrease in the percentages of time spent in the open arms and the frequency in the open arm entries and a significant increase in the percentage of time spent in closed arms. Neuroendocrine and behavioral effects were reversed by GABA agonists, muscimol (2 mg/kg i.p.) and baclofen (10 mg/kg i.p.). In conclusion, chronic DEHP postnatal exposure induced a disruption in the neuroendocrine regulation of the testicular axis in young adult male rats, and this effect was correlated with an anxiety-like behavior. Since GABA agonists reversed these effects, the results suggest that GABA could participate in the modulation of reproductive and behavioral DEHP effects. Fil: Carbone, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina Fil: Ponzo, Osvaldo Juan. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gobetto, María Natalia. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Samaniego, Y.A.. Universidad de Buenos Aires. Facultad de Medicina; Argentina Fil: Reynoso, R.. Universidad de Buenos Aires. Facultad de Medicina; Argentina Fil: Moguilevsky, Jaime Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Favaloro; Argentina Fil: Cutrera, Rodolfo Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentina

Wear of total knee replacement continues to be a significant factor influencing the clinical longevity of implants. Historically, failure due to delamination and fatigue directed design towards more conforming inserts to reduce contact stress. As new generations of more oxidatively stable polyethylene have been developed, more flexibility in bearing design has been introduced. The aim of this study was to investigate the effect of insert conformity on the wear performance of a fixed bearing total knee replacement through experimental simulation. Two geometries of insert were studied under standard gait conditions. There was a significant reduction in wear with reducing implant conformity. This study has demonstrated that bearing conformity has a significant impact on the wear performance of a fixed bearing total knee replacement, providing opportunities to improve clinical performance through enhanced material and design selection.

The research work studies the effect of providing a low dose of bisphenol A (BPA), on the reproductive axis of prepubertal female rats. Wistar mated rats were treated with either 0.1% ethanol or BPA in their drinking water until their offspring were weaned on the 21 day of birth. The estimated average dose of exposure to dams was approximately 3 μg/kg/day. The pups were sacrificed at the 30th day of life. Body weight at the moment of the sacrifice was significantly higher in the group exposed to BPA; ovarian weight and its relative weight were not modified. LH and estradiol levels increased significantly, meanwhile FSH ones showed no significant changes. The number of primary, secondary and atretic follicles increased and antral ones was decreased. Our results demonstrated that early exposure to a low dose of BPA disrupts the normal function of the reproductive axis in prepubertal female rats.

In last few years it has been a significant increase in the consumption of alcohol combined with energy drink. The aim of this work was to study the effect of this mixture in motor and affective behaviors during an alcohol hangover episode. Male Swiss mice received one of the following treatments: saline + sucrose; saline + energy drink; ethanol + sucrose; ethanol + energy drink. Ethanol dose was 3.8 g/kg BW (i.p.) and energy drink dose was 18 ml/kg BW (gavage) at ZT1 (8 am) (ZT: Zeitgeber time; ZT0: 7 am; lights on). The behavioral tests used were tight rope test to determine motor coordination; hanging wire test to study muscular strength; elevated plus maze and open field tests to evaluate anxiety like-behavior and locomotor activity. Tests were carried out at basal point that matched with lights onset and every 6 h up to 18 h after treatments. Hangover onset was established at ZT7 when blood alcohol concentration (BAC) was almost zero. Our results showed that the mixture of alcohol and energy drink altered significantly motor skills. Specifically, a significant decrease was observed in the performance of the animals in the tightrope and hanging wire tests in groups treated with the mixture of alcohol and energy drink. A significant impairment in the anxiety-like behavior was observed mainly at the beginning of alcohol hangover. These findings suggest that energy drink added to alcohol extends motor disabilities observed during an alcohol hangover episode in comparison with animals that received alcohol alone. Fil: Asorey, Lucas Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentina Fil: Carbone, Silvia Elena. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Gonzalez, Bárbara J.. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina Fil: Cutrera, Rodolfo Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentina

New bearing materials for total joint replacement have been explored as the need to improve longevity and enhance performance is driven by the changing demands of the patient demographic. Carbon-reinforced PEEK has demonstrated good wear characteristics in experimental wear simulation in both simple geometry pin-on-plate studies and in total hip joint replacement. Carbon reinforced PEEK CFR-PEEK has the potential to reduce tibial insert thickness and preserve bone in the knee. This study investigated the wear performance of PEEK and CFR-PEEK in a low conformity total knee replacement configuration. Custom-made flat inserts were tested against cobalt-chromium femoral bearings in a knee wear simulation for a period of three million cycles. Wear was assessed gravimetrically at intervals throughout the study. The wear rates of both PEEK and CFR-PEEK were very high and almost two orders of magnitude higher than the wear rate of UHMWPE under comparable conditions. Evidence of mechanical failure of the materials, including surface cracking and delamination was observed in both materials. This study highlights that these materials may not be suitable alternatives for UHMWPE in low-conformity designs., Highlights • Study investigated wear of PEEK and CFR-PEEK as alternative to PE in TKR. • Very high wear rates observed for both PEEK and CFR-PEEK. • Wear rates two orders of magnitude higher than UHWMPE under same conditions. • Evidence of mechanical failure of PEEK and CFR-PEEK materials.

I Rom, Sinti e Caminati piu di ogni altro gruppo che si trovi ai margini della societa possono far riflettere sulla questione dell’integrazione. Ma che ruolo gioca in questo processo la cultura Rom? E di quale cultura stiamo parlando? Nel tentativo di cogliere il loro "cambiamento culturale" si e cercato di decostruire quella rigida immagine identitaria che e stata loro cucita addosso. Sono state fatte 30 interviste in profondita ai Rom di un gruppo di Messina coinvolto in un progetto di integrazione socio-abitativa promosso nel 2011 dal Comune e dal Ministero del Lavoro e delle Politiche Sociali. Ho integrato la raccolta delle interviste con l’osservazione partecipante, raccogliendo cosi dati sul contesto fisico, le abitazioni, il quartiere e lo spazio relazionale dei membri del gruppo Rom. L’obiettivo della ricerca e stato quello di comprendere come i soggetti coinvolti percepiscono la propria cultura e a quali valori attribuiscono maggior importanza. Il risultato che e emerso e l’esistenza di nuovi interstizi nei quali si colloca quel movimento, quel cambiamento culturale in grado di generare integrazione.

Nell’ultimo decennio, l’aumento delle modalita di contatto tra due entita, servizi psichiatrici e familiari, indispensabili entrambe per sostene- re il percorso di riabilitazione individuale del soggetto, ha modificato le richieste e conseguentemente le aspettative, ma ha anche fatto emergere nuove difficolta e conflitti. Puo il moltiplicarsi delle occasioni di contatto, tra operatori e familiari, favorire il sorgere di atteggiamenti di colpevolizzazione da parte degli operatori stessi nei confronti della famiglia, sulla base dell’influenza di quegli orientamenti teorici sistemico-relazionali dell’inizio del XX secolo che riconoscevano nei familiari il loro essere concausa della sofferenza del proprio caro? E come incide tutto cio sulla collaborazione? Questa ricerca e stata condotta presso alcune strutture pubbliche di Roma. La caratteristica del contesto relazionale ha portato a privilegiare come strumenti di analisi le interviste qualitative. Sono state raccolte ventisei interviste.

Total joint replacement is a successful surgical intervention for the treatment of the degeneration of many joints, particularly the hip and knee. As the demand for joint replacement grows, and the life expectancy of the population increases, the performance requirements of these implants also changes. New materials, to improve longevity and enhance performance have been explored including PEEK and CFR-PEEK. \ud \ud \ud This study investigated whether CFR-PEEK and PEEK were appropriate materials for total joint replacement by examining wear performance in simple configuration studies articulating against cobalt chrome under a range of cross-shear and contact pressure conditions. Simple geometry pin on plate studies were conducted for one million cycles for each test condition, with the contact pressure and cross-shear conditions representing a range in which the material may need to operate in-vivo. \ud \ud \ud The wear factor for PEEK was significantly higher than CFR-PEEK and conventional polyethylene under all test conditions. Both PEEK and CFR-PEEK wear were influenced by contact pressure, with the highest wear factors for both materials measured at the highest pressure conditions. PEEK appeared to have a cross-shear dependent wear response, but this was not observed for the CFR-PEEK material. \ud \ud \ud This study has further characterised the wear performance of two materials that are gaining interest for total joint replacement. The wear performance of the PEEK material showed poorer wear performance compared to polyethylene when articulating with a metal counterface, but the performance of the CFR-PEEK material suggested it may provide a suitable alternative to polyethylene in some applications. The wear performance of CFRPEEK was poorer than polyethylene when it was used as the plate, when there was translation of the contact zone over the surface of the CFR-PEEK plate. This has implications for applications in low conforming contacts, such as lower conformity knee replacement.

Immune system disorders are often accompanied by alterations in the reproductive axis. Several reports have shown that administration of bacterial lipopolysaccharide (LPS) has central inflammatory effects and activates cytokine release in the hypothalamus where the luteinizing hormone releasing hormone (Gn-RH) neurons are located. The present study was designed to investigate the effect of repeated LPS administration on the neuroendocrine mechanisms of control of the reproductive axis in peripubertal female rats (30-day-old rats). With this aim, LPS (50 μg/kg weight) was administered to the animals during 25, 27 and 29 days of age and sacrificed on 30 day of life. Gn-RH, γ−amino butyric acid (GABA) and glutamic acid (GLU), two amino acids involved in the regulation of Gn-RH secretion, hypothalamic content were measured. LH and estradiol serum levels were also determined and the day of vaginal opening examined. The results showed a significant increase in Gn-RH and GLU content (p < 0.0001), shared by a reduction of GABA one (p < 0.0001). LH and estradiol serum levels were decreased (p < 0.01, p < 0.001) and delay in the day of vaginal opening was also observed in treated animals. Present results show that repeated LPS administration impaired reproductive function, modifying the neuroendocrine mechanisms of control of the axis in peripubertal female rats.

4-Methylbenzylidene-camphor (4-MBC), an UV-B ray filter, belongs to the endocrine disrupters involved with alterations in the reproductive axis. Our target was to study the effect of 4-MBC on the neuroendocrine parameters that regulate reproduction in prepubertal and peripubertal male rats, which received this disrupter during embryonic and fetal development. 4-MBC was administered (sc) to female rats since pregnancy onset in doses of 20, 100 and 500 mg/kg/day. The litters were sacrificed at 15 or 30 days old to determine testicular weight, gonadotropin and prolactin serum levels and also GnRH and amino acids release from the hypothalamus. The exposure to 20 mg/kg/day only increased the LH serum levels in 30-day-old males. Doses of 100 and 500 mg/kg/day caused a decrease in testicular weight and in LH, GnRH and glutamate levels, in prepubertal rats (15-day-old specimens), and an increase in, gonadotropin (LH and FSH) con-centration and aspartate levels in peripubertal rats (30-day-old specimens), without changes in testicular weight. Prolactinaemia remained unaltered in all groups. Results obtained show that the administration of high doses of 4-MBC during embryonic and fetal stage inhibits the testicular axis in male rats during the prepubertal stage and stimulates it during peripubertad stage. On the other hand in the case of low doses no significant effects were observed.

OMC (octyl-methoxycinnamate), is an endocrine disruptor with estrogenic activity, which is used in sunscreen creams as a UV filter. We studied its " IN VITRO" effects on the hypothalamic release of LHRH as well as on the amino acid neurotransmitter system in immature rats of 15 (prepubertal) and 30 (peripubertal) days of age. OMC decreased the LH-RH release significantly in male and female rats of both age. In male rats OMC increased the release of GABA while in the female ones It diminished the excitatory amino acid aspartate (ASP) and Glutamate (GLU) without modifications in the hypothalamic GABA release. These results suggest that during sexual maturation the inhibitory effect of OMC on LH-RH release appears to be related to its action on the inhibitory and excitatory amino acid neurotransmitters in male and female rats.

The immune, endocrine and nervous systems are closely interrelated, which allows the organism to respond to different types of stress such as infection. Chronic infectious and inflammatory conditions are often accompanied by an impaired reproductive function. Leptin, a hormone produced by adipose tissue, exerts a regulatory function on the reproductive axis. It has homology with other proinflammatory cytokines and could be modified by lipopolysaccharide (LPS). Therefore, these studies were designed to investigate the effect of LPS administration on the neuroendocrine mechanisms involved in the regulation of the reproductive axis during sexual maturation. Fifteen- and 30-day-old female rats were injected with a single dose of LPS 250 µg/kg (i.p.) and then nitric oxide synthase (NOS) activity, hypothalamic excitatory/inhibitory amino acids and Gn-RH content, serum LH and leptin concentration were studied. In 15-day-old female rats LPS treatment did not modify hypothalamic inducible (iNOS) and constitutive (cNOS) NOS activity, Gn-RH, glutamate (GLU) and GABA content. Also serum LH and leptin levels were not modified. In 30-day-old rats LPS increased iNOS and cNOS activity (p < 0.001) and hypothalamic Gn-RH content (p < 0.001). At this age hypothalamic GABA content was significantly decreased (p < 0.001) without changes in GLU content, and serum LH (p < 0.001) and leptin (p < 0.0001) decreased significantly. In summary, current studies have demonstrated that LPS administration to 15- and 30-day-old female rats results in a different response of the hypothalamus-pituitary-gonadal axis and of the adipose tissue, demonstrating an ontogenic response of the immune-neuroendocrine system to LPS administration.

The purpose of the present study was to determine the effect of treatment with leptin on gonadotrophin secretion and hypothalamic GnRH, excitatory and inhibitory amino acids release, in prepubertal (15 days old) and peripubertal (30 days old) male rats. Rats of both ages received a single (ip) injection of 30 microg/kg leptin 60 minutes previous to sacrifice. Serum LH was determined, and the hypothalamus dissected and incubated in Earle's medium. GnRH and amino acids release were determined in the media. LH and GnRH were measured by RIA. Amino acids were assessed by HPLC-UV detection. In the two prepubertal stages, (prepubertal and peripubertal, 15 and 30 days of age respectively) leptin increased plasmatic LH levels (p < 0.01) and hypothalamic GnRH release (p < 0.01). Glutamate (GLU) release showed an increment in leptin-treated rats (p < 0.01) at both ages, while only the 30 days old rats showed an increment of the aspartate (ASP) release. GABA secretion was not modified by leptin treatment. In conclusion, the results demonstrated that leptin stimulates the LH-GnRH axis during sexual development in male rats, increasing the secretion of both hormones. The hypothalamic excitatory amino acid neurotransmitter system appears to be involved in this change.

Leptin, a peptide hormone secreted by adipocytes that has been proposed as a metabolic signal in the reproductive system, appears to be linked to the different neuroendocrine processes involved in the onset of puberty. We studied the ontogenic effect of administration of leptin (30 mg/kg i.p.) on serum LH levels during different stages of sexual development (7, 30, and 45 days of age) in male rats and on the hypothalamic content of glutamate (GLU) and gamma-aminobutyric acid (GABA) in 30-day-old rats. Leptin induced a significant increase (p0.01) in LH levels in 30 days old rats. This hormone stimulatory effect was accompanied by a significant enhancement (p0.01) of the hypothalamic content of glutamate, the hypothalamic excitatory aminoacid involved in N-methyl-D-aspartate (NMDA) neurotransmission. No changes in the LH plasma levels were observed in 7- and 45-day-old male rats treated with leptin. MK 801 (0.1 and 0.3 mg/kg i.p.), an antagonist of NMDA receptors of excitatory amino acid system (EAAs), antagonized the stimulatory effect of leptin on LH secretion and on the hypothalamic content of GLU. These results demonstrate that leptin stimulates the reproductive axis in male rats during a determined period of sexual maturation and that NMDA receptors are involved in thefacilitatory action of leptin on the gonadal axis of male rats during sexual maturation.

GABAergic, serotoninergic and excitatory amino acid systems (EAAs) regulate the prolactin (PROL) secretion in prepubertal female rats. The aim of the present paper was to determine the interrelationships of these systems on the control of this pituitary hormone. It was carried out through the following scheme: 1. The participation of the EAAs and serotonin in the effect of GABAergic system on PROL release, determined by evaluating the GABA A and GABA B receptor agonists. It was carried out on animals that were previously treated with AAEs receptor antagonist or p-chlorophenylamphetamine (PCA), this one depleting serotonin in the hypothalamus. 2. The participation of GABAergic system in the effect of serotonin and EAAs systems, determined by the evaluation of the effects of EAAs receptor agonists and of 5-HTP, a serotonin precursor. With this purpose the rats were previously treated with GABA A and GABA B receptor antagonists. 3. The interrelationships between the EAAs and the serotoninergic systems in the control of PROL secretion, determined (a) by using EAAs agonists (in rats depleted of serotonin by PCA) and (b) using EAAs antagonists (in rats treated with 5-HTP, a serotonin precursor). The administration of GABAergic agonists significantly increased PROL secretion in prepubertal female rats. Neither EAAs antagonists nor the depletion of serotonin in the brain, modified the stimulatory effects of the GABAergic system on PROL levels. This is a clear indication that the activity of the GABAergic system is independent of the serotoninergic and of the EAAs system effects on the pituitary hormone. The EAAs neurotransmitter system agonists significantly increase PROL levels. This effect was blocked by the GABAergic system antagonists but was not modified by serotonin depletion. Taking into account these facts it may be considered that the GABAergic system is involved in the stimulatory effect of EAAs on PROL secretion, this effect being independent of the serotoninergic system. 5-HTP significantly increased PROL plasma levels, and this effect was modified neither by the GABAergic nor by the EAAs receptor antagonists. These results indicate that the stimulatory effect of serotonin on PROL release is independent of the GABAergic and EAAs systems. In conclusion it may be considered that in prepubertal female rats, the GABAergic and serotoninergic systems stimulate PROL secretion by independent mechanisms that do not include EAAs. On the other hand, the effects of EAAs neurotransmission are exerted via the GABAergic system.

The fasting-induced gonadotropin function decrease is unspecific, because in this situation there is a lack of all nutrients. We report here the effect of specific protein lack in the diet during 21 days, on pituitary gonadotropin synthesis and response to exogenous GnRH in adult male rats. We also studied the effect of the aproteic diet (AP) on the positive feedback mechanism in adult female castrated rats. The AP diet decreased significantly, both LH and FSH pituitary concentration and also basal gonadotropin plasma levels in male rats. GnRH produced a significantly increment in LH secretion in both treated and control groups, reaching similar levels after stimulation. Nevertheless, the percentile increment from basal levels in the aproteic group was almost four times the controls, suggesting an increased sensitivity in pituitary response to GnRH in rats fed with AP diet. In female castrated rats, the aproteic diet imposed 3 weeks after the surgery was unable to reduce basal gonadotropin secretion, and so also prolactin secretion. Estradiol/progesterone (EP) administration produced the activation of positive feedback mechanism, increasing significantly LH and FSH secretion in both controls and AP groups. Nevertheless, both gonadotropin responses to EP were significantly greater in rats fed with AP diet. Basal prolactin levels and response to EP were not different between both groups. This results suggest that selective protein lack in a diet, reduced pituitary LH and FSH synthesis and secretion. This type of diet also increments pituitary sensitivity to GnRH administration in male rats, and gonadotropin response to positive feedback mechanism in female rats.

4-Methylbenzylidene camphor (4-MBC) is an ultraviolet absorbent. The objective of this paper was to evaluate the effect of 4-MBC low-dose exposure on the neuroendocrine reproductive regulation in male rats. Wistar male adult rats were injected sc. with 4-MBC during 5 days with a dose of 2 and 10 mg/kg or during 2 days with a dose of 2 and 20 mg/kg. In all rats serum prolactin, LH and FSH concentration were assayed. The hypothalamus of rats injected during 2 days were also dissected to study GnRH release. Rats that received 2 and 10 mg/kg of 4-MBC during 5 days showed a decrease in the LH and FSH serum concentration. In rats injected during 2 days, serum LH decreased with 2 and 20 mg/kg and FSH decreased with 2 mg/kg of 4-MBC. In vitro hypothalamic GnRH release also decreased in these animals. These results show that low doses of 4-MBC inhibit the reproductive axis in adult male rats.

The objective of the present work was to study the effect of a low dose of bisphenol A (BPA), on the reproductive axis of prepuberal male rats exposed to the endocrine disruptor (ED) during gestation and lactation period. Wistar-mated rats were treated with either 0.1 % ethanol or BPA in their drinking water until their offspring were weaned at the age of 21 days. The estimated average dose of exposure to dams was approximately 3 μg/kg/day of BPA. The pups were sacrificed on the 35th day of life. Body weight was measured during the development and at the moment of the sacrifice; testicular and seminal vesicles weight and their respective relative weights were also measured. LH, FSH and testosterone were determined and histological studies of testicular tissue were also performed. Body weight at the moment of the sacrifice was significantly higher in the group exposed to BPA; testicular weight decreased significantly; seminal vesicles weight and relative weights of testes and seminal vesicles were not modified by treatment. LH and FSH serum levels increased significantly after treatment, meanwhile testosterone showed no significant changes. Histological studies showed the lumen of seminal tubes reduced by the presence of immature cells of the spermatic lineage. Our results suggest that pre- and early postnatal exposure to a low dose of BPA disrupts the normal function of the reproductive axis in prepuberal male rats. The effects of the ED may be exerted at different levels of the axis and may be dependent on the dose, manner of administration, and the moment of exposure to the disruptor. Fil: Gámez, Juan Manuel. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina Fil: Penalba, Romina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina Fil: Cardoso, Nancy Patricia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ponzo, Osvaldo. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina Fil: Carbone, Silvia Elena. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pandolfi, Matias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Neuroendocrinología y Comportamiento; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Scacchi, Pablo. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Ciencias Médicas. Departamento de Docencia e Investigación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Reynoso, Roxana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Ciencias Médicas. Departamento de Docencia e Investigación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

In order to evaluate if the changes of the hypothalamic-pituitary-ovary axis that induce a decrease in fertility and modifications in the sexual cycles during senescence involve modifications in the regulatory action of excitatory amino acid neurotransmission on GnRH neurons, we measured the in vitro effects of NMDA on GnRH release by the anterior preoptic and medial basal hypothalamic areas (APOA-MBH) of castrated aging (18 months old) and young (90 days of age) rats. In a second series of experiments the in vivo LH release response to intrahypothalamic (push-pull) administration of NMDA to aged and young castrated female rats was also determined. A similar rate of basal GnRH release was observed in old and young rats during the incubation time. The addition of NMDA to the medium significantly increased GnRH release in both groups; nevertheless, the GnRH release response to NMDA was significantly lower in old (P0.01) than in young rats (Young: Basal: 50 +/- 10; NMDA 15': 410 +/- 63, 22,5': 1,469 +/- 300; Old: Basal: 47 +/- 10; NMDA 15': 210 +/- 30; 22,5': 350 +/- 65 ng/GnRH/mg.protein). The LH levels measured throughout the in vivo experiments indicated that basal LH concentrations were significantly lower in the aged group. The mean LH concentrations (fractions 1 to 6) was significantly lower in the aged group (Young: 3.9 +/- 0.07, Old: 2.4 +/- 0.03 ng/ml, P0.01). The LH release response to NMDA measured 10 min after the intrahypothalamic administration of the glutamate agonist was significantly lower in aged rats (4.2 +/- 1.6 ng/ml) as compared to young animals (18.0 +/- 6.1 ng/ml; P0.05). LH levels in young rats increased to 580% vs., and only 47% in aged rats as compared to previous basal values. In conclusion, present results demonstrate that the GnRH responses to NMDA neurotransmission, which has a predominantly excitatory effects on GnRH neurons, is significantly decreased in old rats, these data give further support to the hypothesis that a decrease in the excitatory inputs to GnRH neurons could be directly involved in the reduction of the hypothalamic-pituitary-ovary axis activity observed during aging.

The present experiments describe the study of the metabolism of 14C-arachidonic acid and the effect of exogenous norepinephrine (NE) on prostanoid production in the anterior preop-tic area

This study investigated the effect of pre and perinatal exposure to di-(2-ethylhexyl) phthalate (DEHP) on the neuroendocrine parameters that regulate reproduction in prepubertal male and female rats. DEHP at doses of 3 and 30mg/kgbw/day was administered orally in the drinking water to dam rats since pregnancy onset until the moment of pups sacrifice at 15 days of age. In these animals gonadotropin serum level and the hypothalamic contents of the amino acids aspartate, glutamate and gamma-aminobutyric acid were determined. No changes in gonadotropin levels and amino acid neurotransmitters were detected at the low dose in both sexes. However, DEHP administered at high dose (30mg/kgbw/day) to dams produced a significant decrease in the inhibitory neurotransmitter GABA and an increase in the stimulatory neurotransmitter aspartate in prepubertal male offspring rats. These modifications were accompanied by gonadotropin serum levels increase. On the contrary, in treated female rats this chemical increased both, aspartate and GABA, which exert a characteristic stimulatory action on gonadotropin in 15-day-old normal females. This study provides new data about changes produced by DEHP on the hypothalamic amino acid neurotransmitters involved in the neuroendocrine reproductive regulation, in prepubertal male and female rat offspring from dams exposed during gestational and lactational periods. These alterations induced by DEHP exposure could be related to the gonadotropin modifications also described in this work, and with changes in the production of sexual hormones previously reported by other authors.

The aim of the present study was to investigate the effects of bisphenol A (BPA) on the neuroendocrine mechanism of control of the reproductive axis in adult male rats exposed to it during pre- and early postnatal periods. Wistar mated rats were treated with either 0.1% ethanol or BPA in their drinking water until their offspring were weaned at the age of 21 days. The estimated average dose of exposure to dams was approximately 2.5 mg/kg body weight per day of BPA. After 21 days, the pups were separated from the mother and sacrificed on 70 day of life. Gn-RH and gamma-aminobutyric acid (GABA) release from hypothalamic fragments was measured. LH, FSH, and testosterone concentrations were determined, and histological and morphometrical studies of testis were performed. Gn-RH release decreased significantly, while GABA serum levels were markedly increased by treatment. LH serum levels showed no changes, and FSH and testosterone levels decreased significantly. Histological studies showed abnormalities in the tubular organization of the germinal epithelium. The cytoarchitecture of germinal cells was apparently normal, and a reduction of the nuclear area of Leydig cells but not their number was observed. Taken all together, these results provide evidence of the effect caused by BPA on the adult male reproductive axis when exposed during pre- and postnatal period. Moreover, our findings suggest a probable GABA involvement in its effect at the hypothalamic level.

OMC (octyl-methoxycinnamate), an endocrine disruptor having estrogenic activity, is used in sunscreen creams as UV filter. We studied its in vitro effects on the hypothalamic release of Gn-RH as well as on the amino acid neurotransmitter system. OMC significantly decreased Gn-RH release in normal male and female rats as well as in castrated rats with substitutive therapy. No effects were observed in castrated rats without substitutive therapy. In males OMC increases the release of GABA, decreasing the production of glutamate (GLU) while in the female decreases the excitatory amino acid aspartate (ASP) and GLU without modifications in the hypothalamic GABA release. These results suggest that OMC acting as endocrine disruptor could alter the sex hormone- neurotransmitter-Gn-RH axis relationships in adult rats. Fil: Carbone, Silvia Elena. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Szwarcfarb, Berta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Reynoso, Roxana María. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Ponzo, Osvaldo Juan. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Cardoso, Nancy Patricia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Ale, E.. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Moguilevsky, Jaime Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Fundación Favaloro; Argentina Fil: Scacchi, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina

The aim of present paper was to study the probable role of glutamic acid (GLU) as a mediator of bisphenol A (BPA) effect at the hypothalamic level and its effects on the reproductive axis of prepubertal male rats.Mated Wistar rats were treated with either 0.1% ethanol (control group, n=10) or BPA (BPA group, n=10) in their drinking water until their offspring were weaned at the age of 21 days. The estimated average dose of exposure to dams was approximately 2.5 mg/kg body weight/day of BPA. At the prepubertal stage (35 days of age), the male rats were sacrificed and Gn-RH and glutamic acid (GLU) release, an amino acid involved in Gn-RH secretion, were measured in hypothalamic samples containing medio basal and anterior preoptic area (MBH-APOA), by RIA and HPLC respectively. LH, FSH serum levels were measured by RIA and testosterone by EQLIA.Gn-RH and GLU release decreased significantly in animals exposed to BPA (p0.001, p0.01). LH, FSH and testosterone serum levels were also decreased by treatment (p0.0001).Present results provide evidence that BPA may act at the hypothalamic level to decrease GLU release which in turn may modify Gn-RH secretion altering the normal function of the axis.

This study investigated the effect of the pre- and perinatal exposure to di-(2-ethylhexyl) phthalate (DEHP) on the neuroendocrine parameters that regulate reproduction in peripubertal male rats. DEHP at dose of 3 and 30 mg/kg. bw/day was administered orally to female rat since pregnancy onset until weaning. The male litters were sacrificed at 30 days of age to determine gonadotropin serum level and the hypothalamic contents of the amino acids aspartate and gamma-aminobutyric acid. No changes in gonadotropin, aspartate and gamma-aminobutyric acid levels were detected at the low dose. DEHP 30 mg/kg. bw/day reduced testis weight and serum FSH, in correlation with a significant increase in the inhibitory GABAergic tone and a reduction in the stimulatory effect of aspartate on gonadotropin level. This study provides unknown data regarding changes in the hypothalamic contents of the amino acid neurotransmitters, which are involved in the neuroendocrine regulation of reproductive axis, in peripubertal male rat offspring from dams exposed to DEHP during gestational and lactational periods. This could be related with the gonadotropin modifications also here described. Fil: Carbone, Silvia Elena. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Szwarcfarb, Berta. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Ponzo, Osvaldo Juan. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Reynoso, Roxana María. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Cardoso, Nancy Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Deguiz, Laura. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina Fil: Moguilevsky, Jaime Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Fundación Favaloro; Argentina Fil: Scacchi, Pablo. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina

To evaluate the effects of the gamma-aminobutyric acid (GABA)ergic system on PRL secretion during sexual development in female rats, aminooxyacetic acid (an inhibitor of GABA-transaminase which increases the hypothalamic GABA concentration) was administered to 12- to 16- and 30-day-old female rats. The increased GABA level in the hypothalamus was accompanied by a significant increase in the serum PRL concentration in rats 16 days of age and a decrease in the serum concentration of the hormone in 30-day-old rats. No changes in PRL levels were observed at 12 days of age. Muscimol, a GABA-A receptor agonist, increased serum PRL concentrations in 16-day-old rats. By contrast, in rats 30 days of age, muscimol induced a significant decrease in PRL levels. On the other hand, the administration of baclofen, a GABA-B receptor agonist, induced a pattern of PRL modification similar to that observed with muscimol, i.e. stimulation in rats 16 days of age and inhibition in 30-day-old rats. These findings indicate that both the stimulatory and inhibitory effects of the GABAergic system on PRL secretion during sexual maturation are mediated by GABA-A and GABA-B receptors. The present results show that during sexual maturation there is a qualitative modification of the effect of the GABAergic system on PRL secretion. These findings could be related to the complex neuroendocrine mechanisms involved in the onset of puberty in the female rat.

In order to evaluate the involvement of estrogen-progesterone (EP) in the effects of N-methyl-D-aspartate (NMDA) receptor stimulation on gonadotropin secretion during sexual development in female rats, NMDA (30 mg/kg sc) was administered to 16- and 30-day-old female rats pretreated with EP. NMDA administration induced increases in plasma LH concentration that were 13.6-fold and 94.5-fold higher, respectively, than those found after NMDA alone. The increase of LH levels induced by NMDA was accompanied by a significant enhancement of the content of GnRH in the anterior and preoptic hypothalamic areas and in the medial basal hypothalamus (APOA/MBH). EP potentiated this increase of GnRH induced by NMDA. NMDA increased plasma FSH levels at 16 days of age, and this increase was inhibited by EP treatment. In 30-day-old rats EP induced FSH release in response to NMDA. This release was not observed in rats treated only with NMDA. In 16-day-old rats EP induced an increase in the concentrations of aspartate, glutamate, and glycine in the anterior and preoptic hypothalamic areas and in the medial basal hypothalamus, the excitatory amino acids involved in NMDA neurotransmission. This effect was not observed in rats of 30 days of age. In summary, the present results show that during sexual maturation ovarian steroids potentiated the LH-releasing response to NMDA probably by acting at the hypothalamic level; furthermore, during sexual maturation there are changes in the response to EP of the hypothalamic concentrations of excitatory amino acids. These findings could be related to the neuroendocrine mechanisms regulating the onset of puberty and the sexual cycle in female rats.

Administration of aminooxyacetic acid, (an inhibitor of γ-aminobutyric acid (GABA)-transaminase which enhances the hypothalamic GABA content) increased luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in prepubertal rats (16 days of age), and decreased the levels of these pituitary hormones in peripubertal rats (30 days of age). Prepubertal and peripubertal female rats were administered with muscimol, a GABAA-antagonist, with baclofen, a GABAB agonist, and with bicuculline, a GABA-antagonist, and the serum concentrations of LH and FSH were determined. In prepubertal rats, muscimol increased both LH and FSH levels, while in peripubertals the GABAA agonist showed the opposite effect, i.e. both gonadotrophins were decreased after its administration. Baclofen lowered serum concentrations of LH and FSH at the different ages studied. Administration of bicuculline produced a decrease in LH and FSH concentrations in prepubertal rats, and an increase of these values in peripubertal rats. These results indicate that GABA exerts a stimulatory tone on gonadotrophin secretion in prepubertal rats and an inhibitory one in peripubertal animals. This effect is most probably mediated by GABAA receptors. It is suggested that the change in the effect on gonadotrophin secretion of the activation of GABAA receptors which takes place during sexual maturation in the female rats is related to the central mechanisms involved in the onset of puberty.

The immune, endocrine and nervous systems are closely interrelated, which allows the organism to respond to different types of stress such as infection. Chronic infectious and inflammatory conditions are often accompanied by an impaired reproductive function. Leptin, a hormone produced by adipose tissue, exerts a regulatory function on the reproductive axis. It has homology with other proinflammatory cytokines and could be modified by lipopolysaccharide (LPS). Therefore, these studies were designed to investigate the effect of LPS administration on the neuroendocrine mechanisms involved in the regulation of the reproductive axis during sexual maturation. Fifteen- and 30-day-old female rats were injected with a single dose of LPS 250 microg/kg (i.p.) and then nitric oxide synthase (NOS) activity, hypothalamic excitatory/inhibitory amino acids and Gn-RH content, serum LH and leptin concentration were studied. In 15-day-old female rats LPS treatment did not modify hypothalamic inducible (iNOS) and constitutive (cNOS) NOS activity, Gn-RH, glutamate (GLU) and GABA content. Also serum LH and leptin levels were not modified. In 30-day-old rats LPS increased iNOS and cNOS activity (p0.001) and hypothalamic Gn-RH content (p0.001). At this age hypothalamic GABA content was significantly decreased (p0.001) without changes in GLU content, and serum LH (p0.001) and leptin (p0.0001) decreased significantly. In summary, current studies have demonstrated that LPS administration to 15- and 30-day-old female rats results in a different response of the hypothalamus-pituitary-gonadal axis and of the adipose tissue, demonstrating an ontogenic response of the immune-neuroendocrine system to LPS administration.

The present investigations were designed to assess the effect of the serotoninergic system on luteinizing hormone (LH) and LH-releasing hormone (LH-RH) secretion in female rats aged 14 and 30 days. The administration of 5-hydroxytryptophan (5-HTP; 75 mg/kg i.p.) increased hypothalamic serotonin (5-HT) concentrations in both age groups, and did not affect hypothalamic norepinephrine (NE) concentration or release. Serum LH levels were raised by 5-HTP in 14-day-old, but not in 30-day-old rats. Basal and KC1- (28 mM) stimulated LH-RH release by incubated hypothalamic fragments was significantly enhanced when 5-HTP was injected previously to 14-day-old animals. In 30-day-old rats, 5-HTP treatment did not modify basal LH-RH release, and decreased the KC1-stimulated LH-RH output. Similarly, the addition of 5-HT (10−7M) to superfused hypothalamic fragments enhanced basal LH-RH release in 14-day-old rats and blocked the increment in LH-RH release evoked by KC1 in 30-day-old rats. the present results show that in 14-day-old female rats, the serotoninergic system (activated in vivo by 5-HTP treatment, or in vitro by 5-HT addition) exerts a stimulatory effect on LH-RH, and thus, on LH release. On the contrary, in 30-day-old animals, stimulated LH-RH secretion was inhibited by 5-HT. Apparently, the hypothalamic NE system is not implicated in this response. The participation of this changing effect of 5-HT on LH-RH/LH release at the onset of puberty is postulated.