Ceruloplasmin and Copper Transport During the Latter Part of Gestation in the Rat

Abstract

We have examined the tissue uptake of 67Cu from ceruloplasmin versus albumin and transcuprein, after its intravenous administration to pregnant rats, in the last 4 days of gestation. 67Cu infused as in vivo-labeled ceruloplasmin remained on ceruloplasmin in the maternal circulation over the 4- to 6-hr time period examined, as determined by gel chromatography and immunoreactivity. That infused as in vitro-labeled serum was initially on transcuprein and albumin but soon also with new ceruloplasmin. On the basis of percent dose as well as total actual Cu transferred (taking into account the sizes of the two plasma Cu pools), ceruloplasmin was the preferred source of Cu for most tissues. Total uptake of Cu from ceruloplasmin was seven times greater than that from albumin and transcuprein for the placenta, whole fetus, and fetal liver. It was 2- to 6-fold greater for other tissues (except liver and kidney). When synthesis of maternal 67Cu-ceruloplasmin (from 67Cu administered on albumin and transcuprein) was inhibited with cycloheximide, uptake by nonhepatic tissues was reduced markedly. In the fetal circulation, entering 67Cu was initially associated with transcuprein and alpha-fetoprotein (or albumin), but then also appeared with ceruloplasmin. Specific receptors for ceruloplasmin were detected on membranes from the placenta as well as fetal liver; mRNA for ceruloplasmin was detected on the endoplasmic reticulum-bound polyribosomes of placenta/yolk sac, and of fetal and maternal liver. We conclude that Cu destined for the fetus is delivered mainly or exclusively by ceruloplasmin. It may enter via placental receptors, arriving in fetal plasma in ionic form, for later incorporation into fetal ceruloplasmin. The importance of ceruloplasmin as a source of plasma Cu for nonhepatic organs is also confirmed.

Skin lesions in alpacas and llamas with low zinc and copper status – a preliminary report

“…It could be suspected that a coloured fleece, with higher mineral contents, exerts higher demands on mineral metabolism, making such animals more susceptible to deficiency syndromes. In different animal species, pregnancy leads to a decrease in body Zn and Cu levels of the mother animal (Dreosti et al, 1968;Gooneratne and Christensen, 1986;Lee et al, 1993;Rombach et al, 2003), due to the increasing mineral requirements of the growing foetus. In herds of animals with a marginal mineral supply, therefore, deficiencies are most likely to clinically affect breeding females first (Dierenfeld et al, 1988) as in our study, which is in contrast to the impression of Rosychuk (1994) that male llamas appear to be overrespresented in Zn-responsive dermatitis cases.…”

Copper binding components of blood plasma and organs, and their responses to influx of large doses of 65Cu, in the mouse

“…This blue, multi-copper oxidase appears to have pleotropic functions and has been referred to as a prototypic "moonlighting" protein (Bielli & Calabrese 2002), capable of oxidizing a variety of substrates -from amines to Fe(II) (Harris 2000;Linder 1991;Linder 2002); scavenging radicals (Linder 2001;Linder 2002); and delivering copper to tissues (Campbell et al 1981;Lee et al 1993), probably via specific receptors (Kataoka & Tavassoli 1985;Linder 2002;Stevens et al 1984). Its apparent role in Fe transport (attributed to its ferroxidase activity) has been of particular recent interest.…”

Concentração de micronutrientes em mães e seus recém-nascidos por ocasião do parto

“…Mesmo assim as concentrações plasmáticas médias de cobre observadas tanto para os grupos de mães quanto para os recém-nascidos, foram menores do que a média aceita como normal, sugerindo uma deficiência que, mesmo com a suplementação, não chegou a ser evitada 20,26,27 .…”