The stereospecificity of tritium distribution in [1-3H]- and [1,2-3H2]-cholesterol and -cholecalciferol

Bell, Philip; Kodíček, E.

doi:10.1042/bj1160755

Cited by 22 publications

(7 citation statements)

References 15 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1). Since only 64% of the 3H in this labelled compound was at C-1 (Bell & Kodicek, 1970) the theoretical minimum ratio that could have been observed on loss of 3H at C-1 in both a-and fl-positions was 8.3. In most tissues the 3H/14C ratio decreased to a smaller extent with the possible exception of lipid extracts of bones, where the ratio was 9.2.…”

Section: E M Lawson and Others Distinct Component In Blood (Fractiomentioning

confidence: 99%

“…It has been further shown that the 25-hydroxycholecalciferol is then converted into a polar fraction peak P, a component of which is formed by a metabolic reaction involving the loss of hydrogen (shown by using 3H) from C-1 (Lawson, Wilson & Kodicek, 1969a,b). It has been suggested that this reaction might involve the introduction of an oxygen function in C-1 with a possible formation of a ketone (Lawson et al 1969b;Bell & Kodicek, 1970;Kodicek, 1970). This fraction is present in a number of tissues, with the intestine containing the highest concentration, and is found in the nuclei of intestinal 22 cells as practically the only vitamin D metabolite.…”

mentioning

confidence: 99%

“…However, it has been shown (Bell & Kodicek, 1970) that the distribution of 3H in the [1,2-3H2]cholesterol, and consequently also in the [1,2-3H2]cholecalciferol derived froin the cholesterol, is 36% in 2ac-+2,B-, 47-49% in ac-and 15-17% in l-position.…”

mentioning

confidence: 99%

“…It is now known that cholecalciferol (vitamin D3) undergoes several metabolic reactions in the body, including the formation of esters (Fraser & Kodicek, 1968a,b,c;Fraser, 1969) and of the glucuronide of a metabolite (Bell & Kodicek, 1969). In addition there is a sequence of metabolic events leading to the formation of a compound that is active in the biochemical reactions necessary for the effective intestinal transfer of Ca2+.…”

mentioning

confidence: 99%

“…1971, 121 hydrogen at C-1 without any loss at C-2. This was made possible by the determination of the stereospecific 3H distribution of the [1,2-3H2]cholecalciferol, which indicated that 64% of the 3H was at C-1 and the rest at c-2 (Bell & Kodicek, 1970).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Synthesis of [1,2-3H2]cholecalciferol and metabolism of [4-14C,1,2-3H2]- and [4-14C,1-3H]-cholecalciferol in rachitic rats and chicks

Lawson¹,

Pelc²,

Bell³

et al. 1971

Biochemical Journal

View full text Add to dashboard Cite

[1,2-3H2]Cholecalciferol has been synthesized with a specific radioactivity of 508 mCi/mmol by using tristriphenylphosphinerhodium chloride, the homogeneous hydrogen catalyst. With doses of 125ng (5i.u.) of [4-14C,i-3H2]cholecalciferol the tissue distribution in rachitic rats ofcholecalciferol and its metabolites (25-hydroxycholecalciferol and peak P material) was similar to that found in chicken with 500ng doses of the double-labelled vitamin. The only exceptions were rat kidney, with a very high concentration of vitamin D, and rat blood, with a higher proportion of peak P material, containing a substance formed from vitamin D with the loss of hydrogen from C-1. Substance P formed from [4-14C,1,2-3H2]cholecalciferol retained 36% of 3H, the amount expected from its distribution between C-I and C-2, the 3H at C-1 being lost. 25-Hydroxycholecalciferol does not seem to have any specific intracellular localization within the intestine of rachitic chicks. The 3H-deficient substance P was present in the intestine and bone 1 h after a dose of vitamin D and 30min after 25-hydroxycholecalciferol. There was very little 25-hydroxycholecalciferol in intestine at any time-interval, but bone and blood continued to take it up over the 8h experimental period. It is suggested that the intestinal 3H-deficient substance P originates from outside this tissue. The polar metabolite found in blood and which has retained its 3H at C-1 is not a precursor of the intestinal 3H-deficient substance P.

show abstract

Section: E M Lawson and Others Distinct Component In Blood (Fractiomentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations