Direct evidence for the function of crustacean insulin-like androgenic gland factor (IAG): total chemical synthesis of IAG.

Insulin-like androgenic gland factor (IAG) is presumed to be a sex differentiation factor so-called androgenic gland hormone (AGH) in decapod crustacean, although the function of IAG peptide has not yet been reported. In this study, we synthesized IAG from the prawn, Marsupenaeus japonicus, and its function was assessed by an in vitro bioassay. As a result, IAG with the insulin-type disulfide bond arrangement showed biological activity, whereas its disulfide isomer did not. These results strongly suggest that the native IAG peptide has an insulin-type disulfide, and it is the decapod AGH.

Efecto de las hormonas sexuales sobre las concentraciones de homocisteína en preeclámpticas y embarazadas normales / Effect of sexual hormones on homocysteine concentrations in preeclamptic and normotensive pregnant women

Objetivo. Establecer los efectos de las hormonas sexuales sobre las concentraciones plasmáticas de homocisteína en preeclámpticas y embarazadas normales. Métodos. Los grupos consistieron en 35 preeclámpticas (grupo A) y 35 embarazadas normotensas (grupo B), consideradas como controles. Las muestras de sangre se recolectaron en todas las pacientes antes del parto y en el grupo de estudio (grupo A) inmediatamente después del diagnóstico. Se midieron las concentraciones de testosterona, testosterona libre, sulfato de dehidroepiandrosterona, androstenodiona, estradiol y homocisteína. Resultados. Se observaron diferencias estadísticamente significativas en la edad gestacional, presencia de proteinuria, peso de los recién nacidos y de la presión arterial sistólica y diastólica (p<0,05). Las concentraciones de testosterona, testosterona libre, sulfato de dehidroepiandrosterona y homocisteína fueron significativamente superiores en el grupo A comparado con los controles (p<0,05). Las concentraciones de estradiol se encontraron disminuidas en el grupo A comparado con los controles (p<0,05). Se encontraron correlaciones positivas fuertes de testosterona, sulfato de dehidroepiandrosterona y testosterona libre y una correlación moderada negativa con las concentraciones de estradiol con las concentraciones plasmáticas de homocisteína (p<0,05). Conclusiones. Las concentraciones plasmáticas de homocisteína son afectadas en forma positiva por testosterona, sulfato de dehidroepiandrosterona y testosterona libre y negativa por el estradiol en pacientes preeclámpticas y embarazadas normotensas (AU)

Objective. To establish the effects of sexual hormones on plasma homocysteine concentrations in preeclamptic and normotensive pregnant women. Methods. There were two groups: group A consisted of 35 preeclamptic patients and group B of 35 normotensive pregnant women used as controls. Blood samples were collected before labor in both grops and immediately after diagnosis in group A. Concentrations of testosterone, free testosterone, dehidroepiandrosterone sulphate, androstenodione, estradiol and homocysteine were measured. Results. There were statistically significant differences in gestational age, the presence of proteinuria, birthweight and systolic and diastolic blood pressure (p<0.05). Testosterone, free testosterone and dehidroepiandrosterone sulphate were significantly higher in group A than in group B (P<.05). Estradiol concentrations were significant lower in the group A than in group B (P<.05). Strong positive and significant correlations were found between testosterone, dehidroepiandrosterone sulphate and free testosterone and a moderate negative correlation was found between estradiol and plasma homocysteine concentrations (P<.05). Conclusions. In preeclamptic and normotensive pregnant women, plasma homocysteine concentrations are positively affected by testosterone, dehidroepiandrosterone sulphate and free testosterone and are negatively affected by estradiol (AU)

Purification of a candidate gonadotrophin surge-inhibiting/attenuating factor (GnSIF/AF) showing MAPK as a possible target.

Gonadotrophin surge-inhibiting/attenuating factor (GnSIF/AF) has been known for over two decades, but its molecular structure has not been completely characterized yet. In the last 20 years, five different putative GnSIF/AF sequences have been published. In this article, we describe a procedure to isolate and characterize GnSIF/AF from bovine follicular fluid, a GnSIF/AF-derived synthetic peptide (SP-GnSIF/AF) was produced, and the intracellular bioactivity of GnSIF/AF was tested for intracellular action with a MAPK-assay. Two different bioactive molecular weight forms of GnSIF/AF were isolated, a 160 kDa heteromeric and a monomeric 40 kDa protein. The 40 kDa form appeared to be a subunit of the 160 kDa protein. The synthetic peptide mimicked the actions of GnSIF/AF, such as inhibition of GnRH-induced LH secretion and attenuation of the MAPK phosphorylation. The two GnSIF/AF candidates do not show similarities with previously published GnSIF/AF sequences. These are the first data showing the influence of GnSIF/AF on intracellular processes involved in GnRH self-priming and that the biological action of GnSIF/AF was preserved in the produced synthetic peptide. The results provide strong evidence that the identified candidate proteins are the true GnSIF/AF.

Correct disulfide pairing is required for the biological activity of crustacean androgenic gland hormone (AGH): synthetic studies of AGH.

Androgenic gland hormone (AGH) of the woodlouse, Armadillidium vulgare, is a heterodimeric glycopeptide. In this study, we synthesized AGH with a homogeneous N-linked glycan using the expressed protein ligation method. Unexpectedly, disulfide bridge arrangement of a semisynthetic peptide differed from that of a recombinant peptide prepared in a baculovirus expression system, and the semisynthetic peptide showed no biological activity in vivo. To confirm that the loss of biological activity resulted from disulfide bond isomerization, AGH with a GlcNAc moiety was chemically synthesized by the selective disulfide formation. This synthetic AGH showed biological activity in vivo. These results indicate that the native conformation of AGH is not the most thermodynamically stable form, and correct disulfide linkages are important for conferring AGH activity.