The influence of riboflavin doses on the urinary excretion of riboflavin and 4-pyridoxic acid was investigated in 6 young men. Doses of crystalline riboflavin and/or pyridoxine were administered on days 10 to 25 using a 6 X 6 Latin square design. The 6 crystalline vitamin doses given were: 0.3 mg and 0.6 mg pyridoxine; 1.2 mg and 2.4 mg riboflavin: 0.3 mg pyridoxine with 1.2 mg riboflavin and 0.6 mg pyridoxine with 2.4 mg riboflavin. On day 28 each subject received 0.06 mg riboflavin. On days 30 to 45, 6 food doses of known riboflavin content were administered to the subjects using a 6 X 6 Latin square design. All crystalline vitamin and food doses were separated by two days. All subjects consumed a constant diet during the experimental period. Twenty-four-hour urine collections were made throughout the study. Urinary riboflavin excretion increased in response to the 1.2 mg and 2.4 mg riboflavin doses but not after the 0.06 mg dose. Urinary riboflavin excretion increased after the milk dose only. Bioavailability of riboflavin in non-fat dry milk, which was estimated by reference to the riboflavin dose response curve, was 61 ± 35 (mean ± S.D.) percent. In 4 of the 6 subjects urinary 4-pyridoxic acid excretion was suppressed when riboflavin was administered with pyridoxine. Additionally, in four subjects the 2.4 mg riboflavin dose depressed urinary 4-pyridoxic acid excretion to a level below that seen with the 1.2 mg riboflavin dose. These results provide additional supporting evidence for a riboflavin/vitamin B-6 interaction. / Graduation date: 1985

The study reported in this thesis is part of an investigation designed to determine the metabolism of thiamine and riboflavin in human subjects who were maintained on controlled diets. Part of this investigation was made during a 30-day experimental period in 1950 and the other part, during a 30-day experimental period in 1951. In the studies of both years, the subjects were maintained on a diet which was adequate in all nutrients except thiamine and riboflavin. With respect to thiamine, each of the 30-day studies was divided into two experimental periods of 15 days each. During the first 15-day period, the National Research Council's recommended allowance of 500 mcg. thiamine per 1000 calories per person per day was tested and in the second period, each subject received 300 mcg. thiamine per 1000 calories daily in the diet. The daily intake (about 1.2 mg.) of riboflavin was constant throughout the whole study. This thesis is a report of the riboflavin phase of the study only. Four women were selected as subjects for each year's 30-day experiment. In general, they were healthy throughout the entire period of the study. Daily micro determinations of the concentration of free (+FMN) and total riboflavin in the serum and daily macro determinations of riboflavin excreted in 24-hour collections of urine were made. Based on the results of the studies of both years, the mean concentration of free (+FMN) serum riboflavin for seven subjects (data for one subject were omitted) was 1.43 and ranged between 0.47 to 3.5 mcg. percent regardless of the different levels of thiamine intake; the mean concentration of total serum riboflavin was 3.22 and ranged from 2.36 to 5.30 mcg. percent. The mean concentration of free (+FMN) riboflavin in the serum was slightly, but not significantly lower on the period of restricted thiamine intake. The mean concentration of total riboflavin increased 0.43 mcg. percent in the period of restricted thiamine intake; this increase was statistically significant. This phenomenon may have been due to the effect of thiamine on the utilization of riboflavin in metabolism; i.e., a decrease in thiamine intake reduces the requirement for riboflavin and is reflected in an increased concentration of riboflavin in the serum. The statistical analysis indicated that the variation among individuals in serum riboflavin concentration is statistically significant. There was no significant day-to-day variation in the riboflavin value in serum during the period of study. The mean daily urinary excretion of riboflavin of three subjects (data for one subject were omitted) in the 1950 study was 382 mcg. per day, and that of four subjects in the 1951 study, 376 mcg. per day. The riboflavin output was about 32 percent of the ingested vitamin in both years' studies. The riboflavin excretion per gram of creatinine ranged from 248 to 474 mcg. / Graduation date: 1951

Graduation date: 1960

Thesis (Ph. D.)--Columbia University, 1932. / Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 23-24.

Thesis (M.S.)--University of Wisconsin--Madison, 1943. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 38-42).

Thesis (B.S.)--University of Wisconsin--Madison, 1941. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1956. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 45-49).

Thesis (M.S.)--University of Wisconsin--Madison, 1954. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 24-26).

Thesis (Ph. D.)--Columbia University, 1932. / Vita. Bibliography: p. 23-24.

Zugl.: Münster (Westfalen), Universiẗat, Diss., 1994.