Iron is not required in the lactoferrin stimulation of thymidine incorporation into the DNA of rat crypt enterocytes.
Lactoferrin has been identified as a factor in human colostrum that accounts for increased incorporation of thymidine into the DNA in an in vitro rat crypt enterocyte bioassay. We have examined lactoferrin-stimulated thymidine incorporation by comparing the effects of iron-free lactoferrin (apolactoferrin) with those of iron-saturated lactoferrin (diferric lactoferrin) under conditions that inhibit the transfer of iron between these iron-binding proteins in the bioassay system. In addition, we have compared the dose-response relationships of diferric lactoferrin and apolactoferrin. The results demonstrated that lactoferrin, independent of iron-binding states, promoted the incorporation of thymidine into the DNA of rat crypt enterocytes. These observations suggest a previously unreported nutritional role for lactoferrin that is independent of its iron-binding capacity.
Nichols
B L
BL
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030.
McKee
K S
KS
Huebers
H A
HA
D000818:Animals; D001059:Apoproteins / Q000494:pharmacology*; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects*; D007501:Iron / Q000502:physiology*; D007504:Iron Radioisotopes; D007781:Lactoferrin / Q000302:isolation & purification / Q000494:pharmacology* / Q000502:physiology*; D007782:Lactoglobulins / Q000494:pharmacology* / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013936:Thymidine / Q000378:metabolism*
D001059:Apoproteins; D007504:Iron Radioisotopes; D007782:Lactoglobulins; C039223:apolactoferrin; D004247:DNA; D007501:Iron; D007781:Lactoferrin; D013936:Thymidine