Dose response to vaginal administration of 1,25-dihydroxyvitamin D3 to cows.
It was previously reported that intravaginal (IVAG) administration of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) might be protective against bovine hypocalcaemia. In the present study, various doses of exogenous 1,25(OH)(2)D(3) were administered IVAG to ovariectomised cows, and the subsequent changes in the biochemical parameters of the blood were measured to assess the characteristics of vaginal absorption. Five cows received 1,25(OH)(2)D(3) IVAG at a dose of 0.125, 0.25, 0.5, or 1.0microg/kg of body weight (BW) or intravenously at a dose of 1.0microg/kg BW. Dosing was at intervals of at least two weeks in a 5x5 Latin square design. Vaginally administered 1,25(OH)(2)D(3) was absorbed in a dose-dependent manner. There was no correlation between the IVAG dose of 1,25(OH)(2)D(3) and subsequent changes in plasma calcium concentrations. The bioavailability of 1,25(OH)(2)D(3) administered IVAG at 1.0microg/kg BW was approximately 93%.
Okura
N
N
Central Veterinary Clinical Center, Kamikawa Chuo Agricultural Mutual Aid Association, Asahikawa, Hokkaido 078-8208, Japan. n-ohkura@mvg.biglobe.ne.jp
Yamagishi
N
N
Naito
Y
Y
Koiwa
M
M
D000042:Absorption; D000282:Administration, Intravaginal; D000818:Animals; D002117:Calcitriol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002118:Calcium / Q000097:blood; D002417:Cattle / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007275:Injections, Intravenous
D002117:Calcitriol; D002118:Calcium