The effect of zinc and magnesium on calcium uptake into the rat duodenum slices.
The experiments were carried out on 80 male Wistar rats, divided into four groups as follows: group 1, treated orally with ZnCl2 at a dose of 10 mg Zn2+/kg for 14 days; group 2, control; group 3, MgCl2-treated at a dose of 5 mg Mg2+/kg; group 4, treated with ZnCl2 plus MgCl2 in the same manner as groups 1 and 3. The influx of calcium into the rat duodenum slices was investigated in vitro by the method of Papworth and Patrick. Over a range of calcium concentrations (0-10 mM) the influx of this element was defined as a sum of a saturable term (active transport) and a linear term dependent on concentration (passive transport). In the zinc-treated rats only the saturable term was affected. The study of this term by Lineweaver-Burk plots showed a decrease of the half-saturation constant, Kt, while the maximal value, Jm, remained unchanged. Moreover, magnesium was shown to interact with zinc at gut level because simultaneous oral administration of Mg2+ and Zn2+ to rats protected them against the inhibition of calcium uptake observed when Zn2+ was given alone.
Witkowska
D
D
Department of Bromatology, Medical Academy of Warsaw, Poland.
Sedrowicz
L
L
Oledzka
R
R
Białek
A
A
D000704:Analysis of Variance; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D004386:Duodenum / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D015032:Zinc / Q000494:pharmacology*
D008274:Magnesium; D015032:Zinc; D002118:Calcium