Myoinositol in Human Neonates: Serum Concentrations and Renal Handling

Abstract

3bound to the membrane (in that it resists washing out by the normal flow of secretions). A firmly bound effect was therefore sought by exposing normal red cells to saliva for 5 min, and then washing, before measuring ouabain-insensitive efflux. Table 2 shows that there was no difference between cells exposed to saliva and then washed, and cells not exposed to saliva. No firmly bound factor was demonstrated.The significance of humoral substances affecting membrane transport remains to be clarified. There does not appear to be any known hormone, for example, which could easily explain the above effect of saliva, whereas simple physical or physicochemical factors would seem to be excluded by the experimental controls. Modification of the cell membrane by uncharacterized circulating or secreted factors may have a bearing on transport processes in general, and possibly on the disturbance of CF in particular. However, the red cell model, as used in this study, has not confirmed that such a mechanism is important in CF. CONCLUSIONIn a preliminary study, the red blood cells of patients with cystic fibrosis were found to show decreased ouabain-insensitive Na+ efflux. The ouabain-sensitive Na+ efflux, total Na+ efflux, and Na+ influx were found to be normal. This information was used to guide the choice of transport parameters in the main study. The effect of cystic fibrosis saliva on normal red cells was not significantly different from that of control saliva, but both Pediat. Res. 12: 3-6 (1978) normal saliva and cystic fibrosis saliva appear to contain a substance which accelerates Na+ transport in the red cell.

Pharmacokinetics and safety of a single intravenous dose of myo-inositol in preterm infants of 23–29 wk

“…It rises rapidly after birth as the renal blood flow redistributes from the renal medulla to the cortex. Thus, urinary losses of intact inositol are high in both the term and preterm newborn, but gradually fall to very low levels in the weeks following birth (4,20). Despite these developmental physiologic mechanisms that affect inositol concentrations, serum levels remain responsive to dietary intake decreasing in both tissue and serum when diets are low in inositol, and rising with supplemented diets (4).…”

Loss of Murine Na+/myo-Inositol Cotransporter Leads to Brain myo-Inositol Depletion and Central Apnea

“…In the normal whole embryo and fetus, the Ins levels continue to drop as the organism approaches term; the levels are higher at E13.5 than at E14.5 or E18.5. This may be related to de novo synthesis of Ins in the mammalian fetus and placenta (14, 39 -41) and reflected in the fetal plasma Ins concentration that is significantly higher than the maternal level at any time during gestation (39,(41)(42)(43). The plasma Ins level rapidly declines after birth (39,42), perhaps demonstrating the ability of SMIT1 to concentrate, at the level of the placenta, the Ins produced by both placental and fetal tissues.…”

“…This may be related to de novo synthesis of Ins in the mammalian fetus and placenta (14, 39 -41) and reflected in the fetal plasma Ins concentration that is significantly higher than the maternal level at any time during gestation (39,(41)(42)(43). The plasma Ins level rapidly declines after birth (39,42), perhaps demonstrating the ability of SMIT1 to concentrate, at the level of the placenta, the Ins produced by both placental and fetal tissues. There is little movement of Ins from mother to fetus or from fetus to mother (42,43).…”

Quantification of myo‐inositol, 1,5‐anhydro‐ D‐sorbitol, and D‐chiro‐inositol using high‐performance liquid chromatography with electrochemical detection in very small volume clinical samples

“…Human infant cord blood MI levels are much higher than adults and during the last trimester of pregnancy gradually decrease to only moderately elevated levels at term delivery (Lewin et al, 1978;Carver et al, 1997). Preterm delivery results in a fall in blood MI while these unstable infants are unable to feed.…”