Vitamin D3 levels in certain sheep tissues at various times after the intramuscular administration of vitamin D3.

Twenty crossbred wethers were injected intramuscularly with 1 X 10(6) IU of Vitamin D3 and four killed at the end of each of five time periods (1, 2, 3, 4 and 7 months). The results indicated that in these sheep dosed with this large dose of vitamin D3, their depletion in this liposoluble vitamin was a long process. The rate of uptake varied for the different tissues examined. Among the various tissues, vitamin D3 was stored primarily in the adipose tissue. One month after administration of vitamin D3, levels amounted to approximately 220 ng/g fresh tissue and 7 months later there were still appreciable amounts of D3 (2.5 ng/g fresh tissue). Kidney, pancreas, liver had also accumulated a significant amount of the administered dose (1st month: 58, 32 and 20 ng/g fresh tissue, respectively) which was retained in these sheep's organs for over 4 months (13, 32 and 15 ng/g fresh weight). In three muscles (heart and two skeletal muscles) appreciable amounts of vitamin D3 were recorded, which remained high until 4 months after administration (over 8 ng/g fresh tissue). The lowest uptake was recorded in the skin (9 ng/g the first month and 4 ng/g fresh weight at the end of experiment). All these results show that vitamin D3 was taken up rapidly by various tissues and was retained for a long period of time.