Age- and sex-dependent stimulation of calcium uptake in duodenal cells by prolactin in vitamin D-deficient rats.
Administration of ovine-prolactin (O-PRL) stimulated Ca2+ uptake in isolated duodenal cells prepared from vitamin D-deficient rats. The time course of this effect was biphasic: uptake activity reached a peak in 2.5 hrs followed by a decrease at 5 hrs to original levels. This stimulatory effect of O-PRL was observed in vitamin D-deficient male, but not in female rats. This stimulatory effect was observed in 16- and 26-week old, but not 9 week old, animals. Increase in Ca2+ uptake in duodenal cells was not due to a decrease in intracellular Ca2+ efflux. We measured serum Ca concentration in vitamin D-deficient female rats and found that serum Ca increased in D-deficient female rats between 16 and 52 weeks whereas a minimal increase was observed in D-deficient male rats. Although prolactin was shown to stimulate duodenal Ca2+ uptake, it appears that the source of the increase in levels of serum Ca in D-deficient female rats was not derived from an increase in Ca2+ uptake by prolactin in duodenum. The increase in serum calcium with time may explain why female D-deficient rats survive longer then male.
Balakir
R A
RA
Laboratory of Biological Chemistry, National Institute on Aging, National Institute of Health, Baltimore, Maryland 21224.
Cheng
L
L
Sacktor
B
B
Liang
C T
CT
D000375:Aging / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D004386:Duodenum / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D008297:Male; D011388:Prolactin / Q000494:pharmacology*; D051381:Rats; D012737:Sex Factors; D014808:Vitamin D Deficiency / Q000378:metabolism*
D011388:Prolactin; D002118:Calcium