Reproductive axis function and gonadotropin microheterogeneity in a male rat model of diet-induced obesity

Olivares, Aleida; Méndez, Juan Pablo; Zambrano, Elena; Cárdenas, Mario; Tovar, Armando R.; Perera-Marín, Gerardo; Ulloa‐Aguirre, Alfredo

doi:10.1016/j.ygcen.2009.12.007

Cited by 27 publications

(25 citation statements)

References 108 publications

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“…Several studies have shown that changes in the mix of LH isoforms may contribute to differences in the response of the female gonad, but less is known about the response in the Leydig cells of the male gonad (Castro-Fernández et al 2000, Perera-Marín et al 2007, Olivares et al 2009. In a rat model of diet-induced obesity, LH bioactivity was reduced, rendering the male hypogonadal (Olivares et al 2010). More acidic forms are predominant in eugonadal men (Bergendah & Veldhuis 2001).…”

Section: Effect Of Prenatal Testosterone Excess On Gonadal Testosteromentioning

confidence: 99%

Pituitary and testis responsiveness of young male sheep exposed to testosterone excess during fetal development

Recabarren¹,

Rojas-García²,

Einspanier³

et al. 2013

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Prenatal exposure to excess testosterone induces reproductive disturbances in both female and male sheep. In females, it alters the hypothalamus-pituitary-ovarian axis. In males, prenatal testosterone excess reduces sperm count and motility. Focusing on males, this study tested whether pituitary LH responsiveness to GNRH is increased in prenatal testosterone-exposed males and whether testicular function is compromised in the testosterone-exposed males. Control males (nZ6) and males born to ewes exposed to twice weekly injections of 30 mg testosterone propionate from days 30 to 90 and of 40 mg testosterone propionate from days 90 to 120 of gestation (nZ6) were studied at 20 and 30 weeks of age. Pituitary and testicular responsiveness was tested by administering a GNRH analog (leuprolide acetate). To complement the analyses, the mRNA expression of LH receptor (LHR) and that of steroidogenic enzymes were determined in testicular tissue. Basal LH and testosterone concentrations were higher in the testosterone-exposed-males. While LH response to the GNRH analog was higher in the testosterone-exposed males than in the control males, testosterone responses did not differ between the treatment groups. The testosterone:LH ratio was higher in the control males than in the testosterone-exposed males of 30 weeks of age, suggestive of reduced Leydig cell sensitivity to LH in the testosterone-exposed males. The expression of LHR mRNA was lower in the testosterone-exposed males, but the mRNA expression of steroidogenic enzymes did not differ between the groups. These findings indicate that prenatal testosterone excess has opposing effects at the pituitary and testicular levels, namely increased pituitary sensitivity to GNRH at the level of pituitary and decreased sensitivity of the testes to LH.

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Section: Effect Of Prenatal Testosterone Excess On Gonadal Testosteromentioning

confidence: 99%

Pituitary and testis responsiveness of young male sheep exposed to testosterone excess during fetal development

Recabarren¹,

Rojas-García²,

Einspanier³

et al. 2013

Reproduction

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“…Of the total recovered immunoreactive LH, 72.8 % was obtained at a basic pH (≥7.5, fractions A and B), 6.3 % at a El contenido de AMPc total se midió en el medio de cultivo a través de radioinmunoensayo en fase líquida (21) . Para ello el trazador 2-0-monosuccinil tirosil-metil éster de AMPc (Sigma) se radiomarcó con Na125I (Amersham International Limite, Reino Unido) mediante el método de la Cloramina-T (29) …”

Section: Resultsunclassified

“…Total cAMP content was measured in the culture medium with liquid phase RIA (21) . The cAMP tracer 2-0-monosuccinyl tyrosyl-methyl ester (Sigma) was labelled with Nal125 (Amersham International Limited, UK) following the chloramine-T method (29) .…”

Section: Determinación De La Actividad Biológica De Las Isoformas De mentioning

confidence: 99%

“…A recently developed alternative is bioassays based on gonadotropin receptor cloning (18,19) . Using a stable cell line derived from HEK-293 cells transfected with rat LH receptor cDNA, evaluations have been done of cAMP production associated with distinct rat hypophysis extracts at a basic pH (20,21) . This same biological model has been used to prove the constant affinity of bovine LH to the rat LH receptor (22) .…”

Section: Introductionmentioning

confidence: 99%

“…This same biological model has been used to prove the constant affinity of bovine LH to the rat LH receptor (22) . transfectada con el cDNA para el receptor de la LH de rata se ha logrado evaluar producción de AMPc asociada con distintos extractos hipofisarios de rata obtenidos a pH básico (20,21) ; así mismo, con este modelo biológico se ha determinado la constante de afinidad de la LH bovina al receptor de la LH de rata (22) .…”

Section: Introductionunclassified

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Biological and immunological activity in bovine luteinizing hormone charge isoforms

Ortega¹,

Olivares

Murcia³

et al. 2016

Rev. Mex. Cienc. Pecu.

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RESUMENLa hormona luteinizante (LH) sufre modificaciones postraduccionales que dan origen a isoformas de carga. El estudio determinó la actividad biológica (B) e inmunológica (I) de distintas isoformas de LH bovina. Las isoformas se aislaron mediante el cromatoenfoque a partir del extracto glicoprotéico obtenido de lóbulos anteriores de hipófisis de bovino. La actividad biológica se evaluó en un bioensayo in vitro midiendo la producción de AMPc. La actividad inmunológica se midió con un radioinmunoensayo (RIA) específico para LH. El USDA-bLH-B5 se utilizó como referencia. Las isoformas se agruparon tomando como referencia el rango de pH de elución, en básicas (A, pH, 10.75-9.75; B, pH, 9.58-8.41), neutras (C, pH, 7.98-6.89) y ácidas (D, pH, 6.88-5.41; E, pH, 5.36-3.46). El peso molecular del heterodímero de cada isoforma y del estándar fue similar, estimado en 36.5 kDa. La actividad inmunológica y biológica se comportó de forma dosis-dependiente. Con respecto al estándar, se requirió una mayor concentración de proteína de cada isoforma para obtener el IC50 en la curva de inhibición. En el bioensayo, el valor EC50 para la producción de AMPc fue significativamente diferente entre isoformas; la isoforma neutra mostró un EC50 inferior lo que se interpretó como la proteína más bioactiva, en contraste, la isoforma ácida, mostró un valor de EC50 superior y resultó ser la menos bioactiva; la básica tuvo un comportamiento intermedio (P<0.05). En conclusión, los resultados sugieren un efecto diferenciado de las isoformas de carga, sobre la producción cuantitativa de AMPc por unidad de LH inmunoreactiva. PALABRAS CLAVE: Hormona luteinizante, Actividad biológica, Actividad inmunológica. ABSTRACT Luteinizing hormone (LH) undergoes posttranslational modifications that originate different charge isoforms. The study evaluated the differences in biological (B) and immunological (I) activity between isoforms of bovine LH.Isoforms were isolated by chromatofocusing from anterior pituitary glycoprotein extract. The biological activity was evaluated in an in vitro bioassay. Immunological activity was measured with a radioimmunoassay (RIA) specific for LH. The USDA-bLH-B5 standard was utilized as the reference. LH isoforms were grouped by their pH range of elution, in basic (A, pH, 10.75-9.75; B, pH 9.58-8.41), neutral (C pH, 7.98-6.89) and acidic (D, pH, 6.88-5.41; E, pH 5.36-3.46). The molecular weight of the heterodimer of each isoform was similar to the LH standard, estimated to be 36.5 kDa. Immunological and biological activity behaved in a dose-dependent manner. With respect to the LH standard, all isoforms required higher protein concentration to reach the IC50 of the inhibition curve. In the bioassay EC50 value for cAMP production was significantly different among isoforms; the neutral isoform showed a lower EC50 which was interpreted as more bioactive, the acidic isoform E showed an EC50 being the least bioactive and the basic was intermediate (P<0.05). In conclusion, the results suggest a quantitative effect of LH charge iso...

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The impacts of yoghurt butter oil on rat testicular morphology and sexual hormones in a 150-day study

et al. 2018

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Reproductive axis function and gonadotropin microheterogeneity in a male rat model of diet-induced obesity

Cited by 27 publications

References 108 publications

Pituitary and testis responsiveness of young male sheep exposed to testosterone excess during fetal development

Pituitary and testis responsiveness of young male sheep exposed to testosterone excess during fetal development

Biological and immunological activity in bovine luteinizing hormone charge isoforms

The impacts of yoghurt butter oil on rat testicular morphology and sexual hormones in a 150-day study

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