Materno-Fetal Transport of Creatine in the Rat

Abstract

The transfer of ¹⁴C-creatine to the rat fetus was studied following continuous i.v. infusion into the mother. In the presence of a relatively constant maternal plasma ¹⁴C-creatine concentration, creatine was accumulated by the chorioallantoic placenta and visceral yolk sac to concentrations higher than that found in maternal or fetal plasma. The ability of the extraembryonic membranes to accumulate creatine changed during gestation; nevertheless, these membranes concentrated creatine against a gradient throughout the period studied (14–22 days of gestation). Neither ¹⁴C-creatinine nor ¹⁴C-urea were concentrated in the placentae or fetal plasma when compared to maternal plasma. Simultaneous infusion of β-guanidinopropionic acid with ¹⁴C-creatine reduced both movement and accumulation of creatine into the fetoplacental unit. It is concluded that the accumulation of creatine by the chorioallantoic placenta and by the visceral yolk sac is an active process with creatine diffusing down its concentration gradient into the fetal circulation.

Creatine synthesis and transport during rat embryogenesis: Spatiotemporal expression of AGAT, GAMT and CT1

“…In CNS, Cr concentration between 5 and 8 mmol/kg wet weight have been found in rat and human fetus, depending on the gestational stage [29,30]. Parts of the developmental needs for Cr can be fulfilled by the active transport of Cr from the mother to the embryo [25,26,31]. GAMT knock-out mice, which develop biochemical alterations comparable to those found in human GAMT deficient patients, present an increase in perinatal mortality [24].…”

“…CT1 mRNA has been shown in the E14 rat embryo, in the entire neuraxis as well as in non-neural tissue [15]. The materno-fetal transport of Cr has been demonstrated [25,26]. As Cr deficiencies lead to severe developmental delay, our aim was to investigate at what time and in which tissues the system for Cr synthesis and transport is expressed during embryonic development.…”

Assessment of glomerular filtration rate in the neonate

“…Creatinine is transported across the placenta [23] and this transport is bidirectional and mostly by simple perfusion. Transport is passive from mother to fetus across the placenta [24,25]. There appears to be an increased…”

Creatine and guanidinoacetate transport at blood‐brain and blood‐cerebrospinal fluid barriers

“…The fetal and perinatal (or immature) brain probably behaves differently. In mammals, the fetal needs in Cr are partly supported by transport of Cr from mother to fetus (Davis et al 1978;Ireland et al 2008;Ireland et al 2011). On the other side, AGAT, GAMT and SLC6A8 are well expressed during embryogenesis, including in CNS (Braissant et al 2005;Ireland et al 2009;Wang et al 2007).…”