Effects of in vivo administration of 1,25-dihydroxyvitamin D3 on in vitro proliferation of bovine lymphocytes.
Continuous infusion of 1,25-dihydroxyvitamin D3 in the bovine elevated 1,25-dihydroxyvitamin D3 in plasma. Plasma 1,25-dihydroxyvitamin D3 remained elevated until infusions were discontinued. Increased 1,25-dihydroxyvitamin D3 was associated with hypercalcemia (11 to 12 mg/dl) that continued for several days postinfusion. Elevated 1,25-dihydroxyvitamin D3 also was associated with a significant 70% enhancement of lymphocyte proliferation in cells treated with concanavalin A. Cessation of infusion of 1,25-dihydroxyvitamin D3 resulted in the return of 1,25-dihydroxyvitamin D3 in plasma and lymphocyte proliferative response to preinfusion amounts. Proliferation in response to pokeweed mitogen was significantly inhibited on d 3 of infusions of 1,25-dihydroxyvitamin D3. Administration of parathyroid hormone for 4 d resulted in a sustained hypercalcemia (approximately 13 mg/dl) and a transient 1-d increase in 1,25-dihydroxyvitamin D3 in plasma. Parathyroid hormone treatment generally did not affect the response of bovine lymphocytes to mitogen. In vivo elevation of 1,25-dihydroxyvitamin D3 is either moderately immunostimulating or exerts no effect on mitogen-stimulated proliferation of lymphocytes. These results contrast with the in vitro results suggesting that 1,25-dihydroxyvitamin D3 is only immunosuppressive.
Hustmyer
F G
FG
Department of Animal Science, Iowa State University, Ames 50011.
Beitz
D C
DC
Goff
J P
JP
Nonnecke
B J
BJ
Horst
R L
RL
Reinhardt
T A
TA
D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D002417:Cattle / Q000276:immunology*; D005260:Female; D066298:In Vitro Techniques; D015918:Infusion Pumps, Implantable / Q000662:veterinary; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D008934:Mitogens / Q000494:pharmacology; D010281:Parathyroid Hormone / Q000502:physiology*; D013223:Statistics as Topic
D008934:Mitogens; D010281:Parathyroid Hormone; D002117:Calcitriol; D002118:Calcium