Radioisotope-dilution technique for determining endogenous manganese in feces of the growing rat

Abstract

A conventional balance study with growing rats was conducted to evaluate experimental conditions for determining endogenous fecal manganese (Mn) excretion and, hence, true Mn absorption by the isotope-dilution technique. Thirty-four rats, with a mean initial live weight of 60 g, allotted to three groups of 8 animals and one group of 10 animals, were injected intramuscularly with a(54)Mn tracer dose and sacrificed after 4, 8, 12, and 16 d, respectively.In liver and serum, the specific radioactivity of Mn was the lowest among the tissues analyzed and its exponential rate of decrease over the period of d 4-16 was the highest. During the 8-d period, from d 9-16, apparent Mn absorption averaged 14.1% of intake (128.5 μg Mn/d). Assuming that the specific activity of Mn in liver of d 11 or, alternatively, in serum of d 16, was on the average representative of that of endogenous Mn in feces of d 9-16, it was computed that Mn of endogenous origin accounted for 9.0 and 9.3% of the total fecal excretion of the metal, and that true absorption amounted to 21.9 and 22.1% of Mn intake, respectively.

Copper, Nickel and Manganese Residues in Tissues and Organs of Rabbits Dosed with Edible Clay

“…The low level of manganese in the various organs and tissues of treated rabbits compared to Ni may be due to the level of the element in the edible clay. Manganese absorption from the gastrointestinal tract is known to be low and depends on the level of intake (Weigand et al, 1986).…”

“…Concentrations of elements like copper for example may accumulate in the liver with no untoward effects (Braide & Anika, 2007;Ochei & Kolhatkar, 2000). Elements like manganese depend on ingestion procedure and are usually low in concentration, being slowly absorbed in the gastrointestinal tract (Weigand, Helbig, & Kirchgessner, 1986). It is pertinent to note that the perseverance of an element in a tissue or organ suggests that the element may have high halflife (Duffus, Worth, & Renwick, 1996;Vander Zanden, Clayton, Moody, Solomon, & Weidel, 2015).…”

Isotope‐dilution technique for determination of endogenous faecal excretion and true absorption of calcium in 45Ca labelled rats

“…As an alternative to calculations of specific 45 Ca activity ratios between tissues and faeces the suitable reference sources may be identified by regression analysis of the slope of the specific activities with increasing time interval after the 45 Ca injection (W eigand et al 1986b). If a tissue is suitable for reference source the slope of its specific 45 Ca activity has to be close to that of the faeces.…”

“…In contrast to this, the isotope‐dilution technique as the third principal tracer method is based on direct measurements under equilibrium conditions (V iseck et al 1953; T hompson 1965; W eigand et al 1986a). The accuracy, reliability and simplicity of the isotope‐dilution technique has been proven especially in trace elements (W eigand and K irchgessner 1976a, b; W eigand et al 1986b; K reuzer and K irchgessner 1991; K irchgessner et al 1994; W indisch and K irchgessner 1994a; G abler et al 1997). In the case of calcium, however, basic studies on the concept of the isotope‐dilution technique were performed only with cattle (V iseck et al 1953) while for monogastric species information on its use is still missing.…”

Isotope‐dilution technique for determination of endogenous faecal excretion and true absorption of selenium in 75Se labeled rats

“…the ‘comparative balance method’, the ‘dual tracer’ or ‘double isotope’ technique, methods based on computerized ‘compartment analysis’ and the ‘isotope‐dilution technique’ (A ubert et al 1963; T hompson 1965; G ibson et al 1988). Especially among these methods, the isotope‐dilution technique comprises direct and quantitative measurements of mineral fluxes and provides robust estimates of endogenous faecal excretions as has been shown for a series of macrominerals and trace elements (W eigand and K irchgessner 1976a,b; W eigand et al 1986a,b; K reuzer and K irchgessner 1991; K irchgessner et al 1994; W indisch and K irchgessner 1994; W indisch et al 1997a). In the case of selenium, endogenous faecal excretion and true absorption was estimated by indirect calculations until now (i.e.…”