The effect of thyroxine and thiouracil on the composition of milk. 3. The concentration of the major constituents and of some of the water-soluble vitamins in cow's milk

Chanda, R.; McNaught, Mary L.; Owen, E.

doi:10.1042/bj0510543

Cited by 16 publications

(5 citation statements)

References 14 publications

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“…DISCUSSION These results confirm our previous observation (i) that the concentration of total riboflavin in the milk of the cow, like that of total thiamine, was not changed by thyroxine. This lack of change of the total is what would be expected since riboflavin, like thiamine, is produced in the lactating ruminant by the rumen bacteria (7), but the lack of effect of thyroxine on the extent of phosphorylation of riboflavin is in marked contrast to its effect on ester phosphorus and on thiamine pyrophosphate in milk, both of which were found in the previous experiments to be much enhanced when thyroxine was injected into the cow (1,10). Possibly the increased mammary metabolism engendered by thyroxine causes a need for energy-rich compounds of phosphoric acid in the mammary epithelium with a disproportionate increase in cocarboxylase and hexose phosphates, for, since the experiments of Chanda These differences between the effects of thyroxine on thiamine and on riboflavin may be associated with the fact that whereas the rat's requirements of thiamine are proportional to its intake of calories from foods other than fats, no such proportionality seems to exist for riboflavin even when the metabolic load is increased by exposing the rats to cold or to the action of thyroxine (13).…”

Section: Methodscontrasting

confidence: 46%

Parition of riboflavin in cow's milk

Modi

Owen

Darroch

1959

Journal of Dairy Research

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Chanda, McNaught & Owen(i) found that injection of thyroxine increased the ratio of bound to free thiamine (vitamin B x ) in the milk of the cow, and Thompson (2) found that ingestion of iodinated casein had the same effect. Injection of thiouracil(i) decreased this ratio, but neither thyroxine nor thiouracil affected the total output of thiamine in the milk. The increase of the bound form engendered by thyroxine was due partly to an increase in thiamine pyrophosphate (cocarboxylase) and partly to an increase in proteinbound thiamine. The riboflavin of cow's milk is partly free and partly combined in a non-ultrafiltrable form (3). The bound riboflavin is in the form of flavinadenine dinucleotide (FAD) for when set free, presumably from protein, by trichloroacetic acid, it behaves like FAD on chromotography or electrophoresis. The following experiments were done to see whether injection of thyroxine affects the partition of riboflavin between its free and its bound forms in cow's milk. EXPERIMENTAL Six Ayrshire cows, 1 month calved, were used. The experiment was divided into Period 1 of 20 days, Period 2 of 14 days and Period 3 of 20 days. During Period 2 three of the cows each received subcutaneously 6-2 mg. L-thyroxine (sodium salt) daily. Total and bound riboflavin were determined in the milk. Milk yields and alkaline phosphatase in the milk and the heart rate of each cow were recorded to show whether the thyroxine was producing its expected physiological effects.Heart rate was recorded at the time of afternoon milking each day. Alkaline phosphatase was estimated by the method of Kay, Aschaffenburg & Neave (4), and total riboflavin in milk by the method of Bessey, Lowry & Love (5) in which the fluorescence of the riboflavin was measured directly in the supernatant liquid from a precipitation of the milk with trichloroacetic acid. After neutralization with K 2 HP0 4 , the fluorescence of the solution was measured in a laboratory-built fluorimeter of the Lowry (6) type as described by Crossland, Owen & Proudfoot(7). To estimate the partition of riboflavin between the free and bound forms a chromatographic separation was made. The milk was treated in the cold with trichloroacetic acid to liberate FAD from its combination with protein.The precipitate was rejected, and the remaining liquid was neutralized with K 2 HPO 4 and extracted with phenol. Addition of ether to the phenol threw out an aqueous phase containing all the riboflavin and the FAD. Residual ether in the separated aqueous phase was evaporated by warming in hot water. Portions of the aqueous extract were chromatographed on Whatman no. 31 paper as described by Crossland et al(l). The riboflavin spot was then eluted and measured fluorimetrically. The difference between the total and that eluted from the chromatogram gave a measure of riboflavin bound to protein as FAD.

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Section: Methodscontrasting

confidence: 46%

Parition of riboflavin in cow's milk

Modi

Owen

Darroch

1959

Journal of Dairy Research

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“…For estimating chloride the method of Davies (1938) and for phosphatase and the partition of phosphorus the procedures used by were adopted. Total thiamine and the partition of thiamine were determined by a slight modification (Chanda, McNaught & Owen, 1952) of the method described by Houston, Kon & Thompson (1940). The reading for each fraction was made in a Spekker fluorimeter in isobutanol as thiochrome (Jansen, 1936).…”

Section: Methodsmentioning

confidence: 99%

“…It was observed by Houston et al (1940) for the milk of cows and goats, and by Braude et al (1947) for sow's milk. Chanda et al (1952) found it to exist in the milk Qf cows treated with thyroxine and thiouracil. The inverse relationship between phosphatase and phosphorylated forms of thiamnine were also shown to hold for cow's milk throughout lactation (Chanda & Owen, 1952b), and also in the milk of cows treated with thyroxine and thiouracil (Chanda, McNaught & Owen, 1952).…”

Section: I953mentioning

confidence: 98%

“…Chanda et al (1952) found it to exist in the milk Qf cows treated with thyroxine and thiouracil. The inverse relationship between phosphatase and phosphorylated forms of thiamnine were also shown to hold for cow's milk throughout lactation (Chanda & Owen, 1952b), and also in the milk of cows treated with thyroxine and thiouracil (Chanda, McNaught & Owen, 1952). It appears therefore that there is a persistent relationship between phosphorylated compounds and phosphomonoesterase whether the changes are produced by mastitis (Table 4 and Fig.…”

Section: I953mentioning

confidence: 98%

“…It appears therefore that there is a persistent relationship between phosphorylated compounds and phosphomonoesterase whether the changes are produced by mastitis (Table 4 and Fig. 4) or are induced artificially by hormones (Chanda et al 1952) or are produced naturally during declining lactation (Chanda & Owen, 1952b). The inverse relationship between phosphatase and phosphorylated thiamine has also been demonstrated in human milk ) and in goat milk (Chanda, 1951).…”

Section: I953mentioning

confidence: 99%

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