Vitamin D-deficient trout at a body weight of about 100 g were
injected intraperitoneally with 1 mCi (19.4 ng) [26,27-3H]
25-hydroxycholecalciferol in 100 ml propylene glycol and blood
was collected 19 h later. Lipid extracts of blood plasma when
chromatographed on Sephadex LH20 revealed two peaks of
radioactivity (Fig. 2). About 55% of the tritium in plasma was