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Aim: Prolactin family hormones include growth hormone, placental lactogen and prolactin, which are able to regulate angiogenesis via NO and prostaglandins. However, their effects on vascular tone are not fully understood. The aim of this study was to evaluate the effects of prolactin family hormones on rat vascular tone in vitro. Methods: Aortic rings were prepared from adult male rats and precontracted with phenylephrine, then treated with the hormones and drugs. The tension was measured with isometric force displacement transducer connected to a polygraph. NO production and prostacyclin release in physiological solution was determined. Cultured rat aortic endothelial cells (RAECs) were treated with the hormones and drugs, and the phosphorylation of eNOS at serine 1177 was assessed using Western bolt analysis. Results: Administration of growth hormone or placental lactogen (0.01-100 nmol/L) induced endothelium-dependent vasodilation. Both the hormones significantly increased the phosphorylation of eNOS in RAECs and NO level in physiological solution. Preincubation with L-NAME blocked growth hormone-or placental lactogen-induced vasodilation and NO production. Preincubation with an antibody against growth hormone receptors blocked growth hormone-and placental lactogen-induced vasodilation. Addition of a single dose of prolactin (0.01 nmol/L) induced sustained vessel relaxation, whereas multiple doses of prolactin induced a biphasic contractionrelaxation effect. The vascular effects of prolactin depended on endothelium. Prolactin significantly increased the level of prostacyclin I 2 in physiological solution. Preincubation with indomethacin or an antibody against prolactin receptors blocked prolactin-induced vasodilation. Conclusion: The prolactin family hormones regulate rat vascular tone, selectively promoting either relaxation or contraction of vascular smooth muscle via activation of either growth hormone receptors or prolactin receptors within the endothelium.

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Obesity and type 2 diabetes(T2D) are the most prevalent and serious metabolic diseases affecting people worldwide. However racial and ethnic disparities seems to be a risk factor for their development. Mexico has been named as one of the largest populations with the highest prevalence of diabetes and obesity. The aim of this study was to identify novel T2D-associated proteins in Mexican patients. Blood samples were collected from 62 Mexican patients with T2D and they were grouped according to their body mass index(BMI). A panel of 10 diabetes and obesity serum markers was determined using MAGPIX. A comparative proteomics study was performed using two-dimensional difference in-gel electrophoresis(2D-DIGE) followed by mass spectrometry(LC-MS/MS). We detected 113 spots differentially accumulated, in which 64 unique proteins were identified, proteins that were involved in metabolism pathways, molecular transport, and cellular signalling. Four proteins(14-3-3, ApoH, ZAG, and OTO3) showing diabetes-related variation and also changes in relation to obesity were selected for further validation by western blotting. Our results reveal new diabetes related proteins present in the Mexican population. These could provide additional insight into the understanding of diabetes development in Mexican population and may also be useful candidate biomarkers.