Possible contribution of(pro)renin receptor to development of gestational diabetes mellitus

(Pro)renin receptor [(P)RR], a receptor for renin and prorenin, was first cloned in 2002. Since then, the pathophysiological roles of(P)RR have been growing concerns.(P)RR binds renin and prorenin, with two important consequences, nonproteolytic activation of prorenin, leading to the tissue renin-angiotensin system activation and the intracellular signalings. It is now also known to play an important role as vacuolar H+-ATPase associated protein, involving in Wnt signaling, main component of embryonic development. Extracellular domain of full-length(P)RR is cleaved in golgi-complex forming soluble(P)RR [s(P)RR]. The s(P)RR is now possible to be measured in human blood and urine. It is now measured in different pathophysiological states, and recent study showed that elevated plasma s(P)RR levels in the early stage of pregnancies are associated with higher incidence of gestational diabetes mellitus later in the pregnancies. Plasma s(P)RR levels of neonates are known to be higher than that of adults. It was also shown that, increased s(P)RR concentrations in cord blood, associated with a lower small for gestational age birth likelihood. These data suggests the involvement of(P)RR in embryo's growth. In thisreview article, we attempt to figure out the possible pathophysiological roles of the(P)RR in maternal glucose intolerance and embryo's growth, through reviewing previous studies.

Growth of embryo and gene expression of nutrient transporters in the small intestine of the domestic pigeon(Columba livia)

The objective of this study was to investigate the relationship between gene expression of nutrient（amino acid, peptide, sodium and proton） transporters in the small intestine and embryonic growth in domestic pigeons（Columba livia）. One hundred and twenty-five fertilized eggs were randomly assigned into five groups and were incubated under optimal conditions（temperature of 38.1 °C and relative humidity of 55%）. Twenty embryos/birds from each group were sacrificed by cervical dislocation on embryonic day（E） 9, 11, 13, 15 and day of hatch（DOH）. The eggs, embryos（without yolk sac）, and organs（head, brain, heart, liver, lungs, kidney, gizzard, small intestine, legs, and thorax） were dissected, cleaned, and weighed. Small intestine samples were collected for RNA isolation. The m RNA abundance of intestinal nutrient transporters was evaluated by real-time reverse transcription-polymerase chain reaction（RT-PCR）. We classified these ten organs into four types according to the changes in relative weight during embryonic development. In addition, the gene expression of nutrient transporters was differentially regulated by embryonic day. The m RNA abundances of b^0,＋AT, EAAT3, y^＋LAT2, Pep T1, LAT4, NHE2, and NHE3 increased linearly with age, whereas m RNA abundances of CAT1, CAT2, LAT1, EAAT2, SNAT1, and SNAT2 were increased to higher levels on E9 or E11 and then decreased to lower levels until DOH. The results of correlation analysis showed that the gene expressions of b^0,＋AT, EAAT3, Pep T1, LAT4, NHE2, NHE3, and y^＋LAT2 had positive correlations with body weight（0.71〈correlation coefficient（CC）〈0.82, P〈0.0001）, while CAT1, CAT2, EAAT2, SNAT1, and SNAT2 had negative correlations with body weight（-0.86〈CC〈-0.64, P〈0.0001）. The gene expressions of b^0,＋AT, EAAT3, LAT4, Pep T1, NHE2, NHE3, and y^＋LAT2 showed positive correlations with intestinal weight（0.80〈CC〈0.91, P〈0.0001）, while CAT1, CAT2, and EAAT2 showed negative correlations with intestinal weight（-0.84〈CC〈-0.67, P〈0.0001）. It was concluded that the differences between growth trajectories of organs and gene expression of nutrient transporters in small intestine were due to their functional and physiological properties, which provided a comprehensive study of amino acid and peptide transporter m RNA in the small intestine during embryonic growth of pigeons.