Plasma carnitine and renal-carnitine clearance during pregnancy

Abstract

This study assessed the time course of decrease in plasma carnitine during pregnancy and compared the renal clearance of carnitine during late pregnancy with nonpregnant women. As early as the 8th wk of pregnancy, the mean (+/- SD) value of total plasma-carnitine concentration in 19 women was significantly decreased from 39.0 +/- 6.3 to 32.8 +/- 4.6 mumol/l and the values continued to fall to 17.3 mumol/l by the 36th wk. The pattern was due to a fall in free-carnitine level; acylcarnitine remained unchanged. In 12 other women examined during late pregnancy, the renal clearance of acylcarnitine was significantly higher than in nonpregnant women, 53.9 +/- 29.4 versus 13.3 +/- 3.0 ml/min, in contrast to free carnitine, 3.5 +/- 2.8 versus 2.8 +/- 1.9 ml/min. Urinary excretion of carnitine (expressed per mol creatinine) did not differ between the two groups. Pregnant women showed sustained excretion of carnitine in the presence of low plasma-carnitine concentrations.

Carnitine status of pregnant women: effect of carnitine supplementation and correlation between iron status and plasma carnitine concentration

“…The present study agrees with other studies ((Bargen-Lockner et al, 1981;Cederblad et al, 1985Cederblad et al, , 1986Genger et al, 1988;Marzo et al, 1994;Schoderbeck et al, 1995;Cho et al, 2003) in showing that plasma carnitine concentrations in women markedly decline during pregnancy. In our study, plasma Table 3 Concentration of g-butyrobetaine and 6-N-trimethyllysine in plasma of women receiving either a L-carnitine supplement (500 mg per day) or a placebo from the 12th week of gestation until delivery at various time points Table 2 Concentration of total carnitine, free carnitine and carnitine esters in plasma of women receiving either a L-carnitine supplement (500 mg per day) or a placebo from the 12th week of gestation until delivery at various time points carnitine concentration at delivery in the placebo group was approximately 40% lower than that at week 12 of pregnancy.…”

“…Physiologically, plasma carnitine concentrations are strongly controlled by the renal excretion of carnitine (Rebouche and Seim, 1998). It has been found that urinary excretion of carnitine even declines during pregnancy and paralleled plasma carnitine concentrations (Cederblad et al, 1986;Marzo et al, 1994). Therefore, an increased renal excretion of carnitine can be ruled out as a possible reason for the low plasma carnitine concentrations during late pregnancy.…”

“…Plasma carnitine concentrations, however, decrease in women during gestation. At the time of delivery, plasma carnitine concentrations decrease to about half of the concentrations of non-pregnant women (Bargen-Lockner et al, 1981;Cederblad et al, 1985Cederblad et al, , 1986Genger et al, 1988;Marzo et al, 1994;Schoderbeck et al, 1995), even though dietary carnitine intake increase, as gestation proceeds (Cho et al, 2003). Similar low carnitine concentrations are only found in patients with carnitine deficiency (Duran et al, 1990).…”

Effects of Prenatal Treatment with Betamethasone,L-Carnitine, or Betamethasone-L-Carnitine Combinations on the Phosphatidylcholine Content and Composition of the Foetal and Maternal Rat Lung

“…Phosphatidylcholine Even in normal pregnancies plasma carnitine levels at species are by far the most abundant component of delivery are decreased to about half of the concentrathe phospholipid fraction. Dipalmitoyl phosphatidylcho-tions seen in non-pregnant women (7)(8)(9)(10). As shown line (l,2-dipalmitoyl^72-glycero-3-phospho-choline) is for rats, maternal carnitine levels are also significantly mainly responsible for surface activity (1,2).…”

Examination of blood plasma content of carnitine and lipids in Haflinger mares during gestation period and early lactation

“…Während der Schwangerschaft kommt es zu einem Abfall der Gesamtcarnitinkonzentration im Plasma bis hin zur Geburt. Daraus wurde geschlussfolgert, dass wäh-rend der Schwangerschaft ein erhöhter Carnitinumsatz erfolgt (Scholte et al 1978;Genger et al 1988aGenger et al , 1988bBargenLockner 1981;Cederblad et al 1986;Peulecke 1995). strum geschuldet sowie, wenn auch in geringerem Maße, der täglichen Abgabe mit der reifen Milch.…”