Sex differences due to dehydroepiandrosterone (DHEA) feeding affecting dehydroepiandrosterone sulfate secretion in golden Syrian hamsters.

The metabolism of orally administered dehydroepiandrosterone (DHEA) by male and female golden Syrian hamsters was examined by quantification of DHEA and dehydroepiandrosterone sulfate (DHEAS) in gallbladder bile, urine and feces using high-performance liquid chromatography (HPLC). Plasma levels of DHEA and DHEAS were also determined by radioimmunoassay (RIA). After 5 days of oral DHEA administration (100 mg/kg body weight twice a day), RIA showed that plasma levels of DHEA and DHEAS were increased approximately 3-6 and 4-5 times, respectively, compared to controls. More than 95 % of circulating DHEA (S) in the peripheral blood was DHEAS. There was no significant sex difference in DHEAS plasma levels between male and female animals in the DHEA-supplemented group. However, 0.2 - 0.3 % of ingested DHEA was conjugated to DHEAS and excreted in urine by females, whereas less than 0.002 % was excreted in urine by males (p < 0.005). DHEAS was excreted in bile by males after DHEA supplementation, and the sex differences in DHEAS levels observed in bile were statistically significant (male, 18.7 +/- 7.5 vs. female, 5.6 +/- 3.1 micromol/l) (p < 0.005). Small amounts of ingested DHEA were excreted in an unchanged state in feces, and no sex difference was observed. These results suggest that there is a considerable sex difference in the conjugation and excretion of orally administered DHEA in the hamster.

Newly established assay method for 25-hydroxyvitamin D3 24-hydroxylase revealed much lower Km for 25-hydroxyvitamin D3 than for 1alpha,25-dihydroxyvitamin D3.

An accurate assay method of 25-hydroxyvitamin D3 24-hydroxylase (24-hydroxylase) was established. Kidney mitochondria prepared from vitamin D-replete rats were treated with polyoxyethylenesorbitan monolaurate. The solubilized suspension was ultracentrifuged at 100,000g for 60 minutes and an aliquot of the supernatant was incubated under the saturating concentrations of substrate NADPH and the mitochondrial-type electron transferring proteins, adrenodoxin and NADPH-adrenodoxin reductase. Products were analyzed by high-performance liquid chromatography (HPLC) monitoring effluents at a wavelength of 265 nm. The maximal velocity of the enzyme in vitamin D-replete rats was 400 pmol/minute per mg of protein, which was considerably higher than those reported by previous authors who used intact kidney mitochondria as the enzyme source. In applying the new assay method, an interesting property was found; Michaelis constant of 24-hydroxylase for 25-hydroxyvitamin D3 [25(OH)D3] was 0.6 microM, which was 35-fold lower than that for 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] which was 20.9 microM. This fact indicates that affinity of the enzyme to 25(OH)D3 is 35-fold higher than that to 1alpha,25(OH)2D3. These data suggest that 25(OH)D3 is the preferred substrate to 1alpha,25(OH)2D3.

Purification and characterization of 25-hydroxyvitamin D3 1alpha-hydroxylase from rat kidney mitochondria.

We purified extensively 25-hydroxyvitamin D3 1alpha-hydroxylase (calcidiol, NADPH: oxygen oxidoreductase (1-hydroxylating), EC 1.14.13.13) from kidney mitochondria of rachitic rats and disclosed its peculiar properties as a P450. The final preparation was identified as a 55 kDa protein having an intense absorption at 417 nm characteristic of P450. The specific activity was 4.8 nmol/min/mg of protein indicating a 350-fold purification. Specific content of P450 was 1.1 nmol/mg of protein and turnover number was 4.4 min-1.

[Prevalence estimates for non-insulin dependent diabetes mellitus (NIDDM) in Japan from National Survey of Circulatory Disorders 1990 data].

Prevalence of diabetes mellitus in Japan was estimated from fructosamine and hemoglobin A1c measurement data obtained from the National Survey of Circulatory Disorders 1990, using a previously reported method which used the results of a screening test for estimating true prevalence. The prevalence for males was higher than that for females. The prevalences were less than 10% for those 49 years or younger and approximately 20% for those 50 years or older. The estimated values derived from fructosamine or hemoglobin A1c did not vary considerably.

[A method of estimation for prevalence of diabetes mellitus from fructosamine levels].

A method for estimating the prevalence interval of diabetes mellitus from fructosamine data is presented, which is based on the previously reported method for estimating prevalence from results of screening tests and on the results of 75 gram glucose tolerance test and fructosamine test in 1,359 examinees. Where true prevalences are 1-20% and population size is 100-10,000, the estimates for prevalence of diabetes mellitus are generally minimum when a screening level of 310 mumol/l of fructosamine is utilized. In our method, a screening level for fructosamine of 310 mumol/l was specified. Standard error ratios of estimated prevalence of diabetes mellitus to true prevalence in a population with an actual prevalence of 10% were about 40% for a population of 200 persons, and about 20% for 2,000 persons or more.

[Efficacy of hemoglobin-Alc, fructosamine, and 1,5-anhydroglucitol in community screening for diabetes mellitus].

To evaluate the efficacy of hemoglobin-Alc, fructosamine, and 1,5-anhydroglucitol tests in screening for diabetes mellitus in communities, the sensitivity and the specificity of these tests were observed on the island of Ojika, Goto islands, Nagasaki prefecture Japan. A 75 gram glucose tolerance test was performed simultaneously on every participant, and WHO diabetes mellitus criteria were used to classify individuals. A total of 554 males and 820 females, older than 34 years, participated in the examination, representing a response rate of 42% and 52% respectively, and 86 were classified as diabetic. The sensitivity and the specificity of several screening levels were determined for each test. Each of the tests attained greater than 70% sensitivity and specificity simultaneously, but could not achieve greater than an 80% level simultaneously. If screening levels are selected for a sensitivity of as low as 50%, it is possible to produce a high specificity of 97-98%. These results provide valuable information for the planning of efficient diabetes mellitus detection programs in communities.

[The prevalence of diabetes mellitus and impaired glucose tolerance studied by 75 gram oral glucose tolerance test in a rural island population].

A mass health examination was performed to assess the glucose tolerance of inhabitants of the island of Ojika, in the Goto islands, Nagasaki prefecture Japan. There were 554 males and 820 females older than 34 years who participated in the mass health examination, a response rates of 42 percent and 52 percent for males and females respectively. Serum glucose levels after overnight fasting and at 2 hours after a 75 gram oral glucose tolerance were used with WHO criteria to classify individuals. Among these subjects, the prevalence of diabetes mellitus increased with age, with a prevalence of diabetes mellitus of around 10 percent in the older subjects. The prevalence for males was higher than that for females. Prevalences of impaired glucose tolerance were roughly in the 15-25 percent range and did not show clear differences among different age groups and sexes. From a questionnaire survey of all island inhabitants, it was considered that the degree of bias of the results was small, if any. The true prevalence for all the inhabitants may be a little larger than the observed prevalence of these subjects.