Plasma Concentrations Of 25-hydroxyvitamin D3 Research Articles

Plasma 25-hydroxyvitamin D3 concentrations and incident risk of ischemic stroke in rural Chinese adults: New insight on ceiling effect

ObjectiveThe aim of this study was to investigate the relationship between 25-hydroxyvitamin D3 (25[OH]D3) and ischemic stroke and its potential modifying factors in rural Chinese adults. MethodsThis nested case-control study was drawn from the H-type Hypertension and Stroke Prevention and Control Project, a community-based, prospective, observational study. Plasma 25(OH)D3 was measured by liquid chromatography with tandem quadrupole mass spectrometry. All stroke records came from the Chinese Center for Disease Control and Prevention. Multiple logistic regression models were used to evaluate the association between 25(OH)D3 and risk of ischemic stroke. ResultsWe included 1079 participants with ischemic stroke and 1079 matched controls. Due to a non-linear relationship, the analyses were stratified by 25(OH)D3. For those with 25(OH)D3 < 20 ng/mL, there was a 15% reduction in the risk of ischemic stroke for each SD increment in 25(OH)D3 (odds ratio, 0.85; 95% confidence interval, 0.73–0.99). Compared with the lowest-tertile group, the risk of ischemic stroke decreased by 39% (odds ratio, 0.61; 95% confidence interval, 0.41–0.89) in the highest-tertile group. Furthermore, two effect modifiers were identified: diabetes and homocysteine level. Although participants with 25(OH)D3 ≥ 20 ng/mL had the lowest risk of ischemic stroke overall, there was no dose-response association within that range. ConclusionsAn inverse dose-response association between 25(OH)D3 and incident risk of ischemic stroke in rural Chinese adults was only observed in those with 25(OH)D3 < 20 ng/mL, along with two effect modifiers. Higher levels of 25(OH)D3 did not confer additional benefit.

Influence of the Biofield Energy Treatment on the Pharmacokinetics of 25-Hydroxyvitamin D3 in Male Sprague-Dawley Rats after a Single Oral Dose of Vitamin D3

Vitamin D3 reported having many important roles in bone metabolism, osteoporosis, immunity, and useful in numerous diseases, i.e., cardiovascular, cancers, and neurodegenerative diseases. Unexpectedly, there is little information available about the concentration of 25-hydroxyvitamin D3 in the blood, which is the best indicator of vitamin D3 status after its oral absorption. However, the biological activity of vitamin D3 is mediated via the formation of the active metabolite, 1-α, 25-dihydroxyvitamin D3 . There are several factors that affect its absorption and first-pass metabolism that lead to having very low plasma concentrations of both the metabolites (25-hydroxyvitamin D3 and 1-α, 25-dihydroxyvitamin D3 ) following an oral administration. Thus, the current study was executed to determine the influence of the Trivedi Effect®-Consciousness Energy Treatment on vitamin D3 and rats through the measurement of plasma 25-hydroxyvitamin D3 concentrations after the oral administration of vitamin D3 in male Sprague-Dawley rats. The test item, vitamin D3 was divided into two parts. One part was denoted as the control (without Biofield Energy Treatment/Blessing), while the other part was defined as the Biofield Energy Treated sample, which received the Biofield Energy Treatment by renowned Biofield Energy Healer, Dahryn Trivedi. Additionally, one group of animals also received Consciousness Energy Treatment per se by the Healer under similar conditions. The Biofield Energy Healer who was located in the USA, while the test samples and animals were located in the research laboratory in India. Vitamin D3 oral formulations were administrated by oral gavage at a dose of 500 µg per kg in groups viz. G1 (untreated vitamin D3 ), G2 (Biofield Treated vitamin D3 ), and G3 (Biofield Treated animals received untreated vitamin D3 ) group. The Biofield Energy Treatment increased the maximum plasma concentration (Cmax) of 25-hydroxyvitamin D3 by 3.45% and 72.77% in the G2 and G3 groups, respectively as compared with the G1 group. The area under the plasma concentration– time curve (AUC0–t) of 25-hydroxyvitamin D3 was altered by -11.19% in the G2 group and 59.45% in the G3 group as compared to the G1 group. After oral administration, the Tmax of 25-hydroxyvitamin D3 was altered by -62.97% in G2 and 55.56% in G3 groups compared to G1. The mean residence time (MRT) of 25-hydroxyvitamin D3 was also altered in the G2 group by -12.34% and G3 group by 0.18%, as compared to the G1. The relative oral bioavailability (Fr) of 25-hydroxyvitamin D3 was significantly altered by -11.19% in the G2 group and 59.45% in the G3 group compared to the G1. Biofield Energy Treatment could be an innovative strategy that opens new avenues to overcome poorly absorbed pharmaceuticals/ nutraceuticals/herbal extracts and can also improve the therapeutic performance of orally active molecules.

Plasma 25-Hydroxyvitamin D3 Concentrations and Risk of New-Onset Proteinuria in Patients With Hypertension

We aimed to evaluate the relationship of plasma 25-hydroxyvitamin D3 (25[OH]D3) with the risk of new-onset proteinuria and examine the possible effect modifiers in patients with hypertension and without chronic kidney disease at baseline. This is a post hoc analysis of the renal substudy of the China Stroke Primary Prevention Trial. A total of 1655 patients with hypertension, who had plasma 25(OH)D3 measurements, as well as without proteinuria and with an estimated glomerular filtration rate of ≥60mL/min/1.73m2 at baseline, were included in the present study. The main outcome was new-onset proteinuria, defined as a urine dipstick reading of ≥1+ at the exit visit. The mean (standard deviation) 25(OH)D3 level at baseline was 18.6 (7.5) ng/mL. The median follow-up duration was 4.4years. Overall, there was a significant inverse association between plasma 25(OH)D3 and the risk of new-onset proteinuria (per standard deviation increment; [odds ratio] OR: 0.70; 95% confidence interval [CI]: 0.50, 0.97). Accordingly, when 25(OH)D3 was assessed as quartiles, a significantly lower risk of new-onset proteinuria was found in participants in quartiles 3-4 (≥17.8ng/mL; OR: 0.45; 95% CI: 0.23, 0.87), compared with those in quartile 1 (<13.1ng/mL). Furthermore, a stronger inverse relationship of plasma 25(OH)D3 and new-onset proteinuria was observed in nondiabetic participants (per standard deviation increment; OR: 0.57; 95% CI: 0.39, 0.83; vs. diabetics: OR: 1.48; 95% CI: 0.67, 3.28; P for interaction=0.028). There was a significant inverse association between plasma 25(OH)D3 and the risk of proteinuria in patients with hypertension, especially in those without diabetes.

Comparison of the Association between Circulating Vitamin D3 Levels and Clinical Outcomes in Patients with Asthma and Chronic Obstructive Pulmonary Disease: A Prospective Observational Study.

Vitamin D has an immune-modulating effect, related to the pathophysiology of asthma and chronic obstructive pulmonary disease (COPD). However, few studies have focused on the difference between patients with asthma and COPD in the association of circulating vitamin D levels with clinical outcomes. We sought to investigate the associations of circulating vitamin D levels with health-related QOL (HR-QOL), severity, and exacerbations. Subjects included 152 asthma patients and 50 COPD patients. We measured plasma concentrations of 25-hydroxyvitamin D3 [25(OH)D3]. HR-QOL was assessed using the EuroQoL 5-Dimension (EQ-5D) and the 12-item Short Form Health Survey (SF-12) scales. Exacerbations were recorded during a one-year follow-up. Associations between plasma 25 (OH)D3 concentrations and outcome variables were evaluated using linear regression. Plasma concentrations of 25(OH)D3 were positively associated with the EQ-5D index value and the SF-12 physical component score in patients with asthma; however, such associations were not observed in patients with COPD. A significant association between severity and plasma concentrations of 25(OH)D3 was found only in patients with COPD. The hazard ratios (95% confidence interval) of plasma 25(OH)D3 concentrations (per 1 ng/mL decrease) for time to first exacerbation was 1.38 (1.10-1.75; p = 0.006) and 0.95 (0.87-1.03; p = 0.179) in patients with COPD and asthma, respectively. Lower concentrations of plasma 25(OH)D3 contributed to lower HR-QOL in patients with asthma, and were associated with severity and risk of future exacerbations in patients with COPD.

Effects of prepartum dietary cation-anion difference and source of vitamin D in dairy cows: Vitamin D, mineral, and bone metabolism

Pregnant Holstein cows, 28 nulliparous and 51 parous, were blocked by parity and milk yield and randomly allocated to receive diets that differed in dietary cation-anion difference (DCAD), +130 or -130 mEq/kg, and supplemented with either calcidiol or cholecalciferol at 3 mg/11 kg of dry matter from 255 d of gestation until parturition. Blood was sampled thrice weekly prepartum, and on d 0, 1, 2, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 postpartum to evaluate effects of the diets on vitamin D, mineral and bone metabolism, and acid-base status. Blood pH and concentrations of minerals, vitamin D metabolites, and bone-related hormones were determined, as were mineral concentrations and losses in urine and colostrum. Supplementing with calcidiol increased plasma concentrations of 25-hydroxyvitamin D3, 3-epi 25-hydroxyvitamin D3, 25-hydroxyvitamin D2, 1,25-dihydroxyvitamin D3, and 24,25-dihydroxyvitamin D3 compared with supplementing with cholecalciferol. Cows fed the diet with negative DCAD had lesser concentrations of vitamin D metabolites before and after calving than cows fed the diet with positive DCAD, except for 25-hydroxyvitamin D2. Feeding the diet with negative DCAD induced a compensated metabolic acidosis that attenuated the decline in blood ionized Ca (iCa) and serum total Ca (tCa) around calving, particularly in parous cows, whereas cows fed the diet with positive DCAD and supplemented with calcidiol had the greatest 1,25-dihydroxyvitamin D3 concentrations and the lowest iCa and tCa concentrations on d 1 and 2 postpartum. The acidogenic diet or calcidiol markedly increased urinary losses of tCa and tMg, and feeding calcidiol tended to increase colostrum yield and increased losses of tCa and tMg in colostrum. Cows fed the diet with negative DCAD had increased concentrations of serotonin and C-terminal telopeptide of type 1 collagen prepartum compared with cows fed the diet with positive DCAD. Concentrations of undercarboxylated and carboxylated osteocalcin and those of adiponectin did not differ with treatment. These results provide evidence that dietary manipulations can induce metabolic adaptations that improve mineral homeostasis with the onset of lactation that might explain some of the improvements observed in health and production when cows are fed diets with negative DCAD or supplemented with calcidiol.

Interspecies differences in plasma concentrations of 25-hydroxyvitamin D3 and dermal Vitamin D synthesis of kiwi (Apteryx mantelli), tuatara (Sphenodon punctatus), and New Zealand sea lions (Phocarctos hookeri).

Vitamin D plays a central role in calcium homeostasis of most vertebrates, and is obtained in different species through diet, dermal synthesis, or a combination of both. The aim of this study was to determine the predominant routes of Vitamin D synthesis in three disparate species, brown kiwi (Apteryx mantelli), tuatara (Sphenodon punctatus), and New Zealand sea lions (Phocarctos hookeri). We surveyed plasma concentrations of 25-hydroxyvitamin D2 and D3, analysed environmental conditions and life history factors, and determined the ability of skin samples to synthesise Vitamin D3 on exposure to ultraviolet-B radiation. There was variation in the plasma/serum 25-hydroxyvitamin D3 concentrations between and within the species studied, with wild kiwi having the lowest concentrations and NZ sea lions the highest. Kiwi skin produced small but measurable amounts of Vitamin D3, while tuatara skin produced Vitamin D3 concentrations higher than that of kiwi. New Zealand sea lion skin produced the highest amount of Vitamin D3 and differed from the other two species in this study in that Vitamin D3 was present in skin before UV-B exposure. The results from this study show that all three species studied retained the ability to use both dietary and dermal sources of Vitamin D, although there was interspecies variation in the magnitude of dermal synthesis. Comparisons between these species show that there are differences in their Vitamin D pathways, but suggest that there are more factors contributing to these pathways than might be expected solely from life history characteristics.

Plasma Levels of 25‐Hydroxyvitamin D3 and In Vivo Markers of Cytochrome P450 3A Activity in Swedes and Koreans: Effects of a Genetic Polymorphism and Oral Contraceptives

In vitro studies have shown that vitamin D may induce several cytochrome P450 (CYP) enzymes in general and CYP3A4 in particular. The primary aim of this study was to investigate the relationship between plasma levels of 25-hydroxyvitamin D3 and suggested in vivo markers of CYP3A activity in healthy volunteers from Sweden and Korea. Plasma concentrations of 25-hydroxyvitamin D3 were analysed in samples from three previously performed studies, and the correlation between these levels and suggested in vivo markers of CYP3A activity was investigated by means of nonparametric correlation. In addition, we studied the modulating effects of three vitamin D receptor promoter polymorphisms on the association between 25-hydroxyvitamin D3 and CYP3A enzyme activity in Swedish subjects. The plasma levels of 25-hydroxyvitamin D3 were not significantly associated with CYP3A phenotypes in any of the three studies, but after accounting for the vitamin D receptor polymorphism rs4516035, there was a significant positive association between 25-hydroxyvitamin D3 and CYP3A activity (p = 0.004). Swedes (n = 65) had significantly higher 25-hydroxyvitamin D3 levels than Koreans (n = 67), 75 nM compared with 31 nM (p < 0.001). Swedish women taking oral contraceptives (OC) (n = 19) had somewhat higher plasma levels of 25-hydroxyvitamin D3 compared with Swedish women not taking oral contraceptives (n = 21), 89 and 72 nM, respectively (p = 0.02). In conclusion, our results suggest that the overall influence on the CYP3A activity by 25-hydroxyvitamin D3 is of marginal importance.

Plasma 25-hydroxyvitamin D3 concentrations in Hermann's tortoises (Testudo hermanni) exposed to natural sunlight and two artificial ultraviolet radiation sources

Objective-To determine the effect of various UVB radiation sources on plasma 25-hydroxyvitamin D(3) concentrations in Hermann's tortoises (Testudo hermanni). Animals-18 healthy Hermann's tortoises. Procedures-Tortoises were exposed to sunlight in an outdoor enclosure located in the natural geographic range of Hermann's tortoises (n = 6 tortoises) or a self-ballasted mercury-vapor lamp (6) or fluorescent UVB-emitting lamp (6) in an indoor enclosure for 35 days. Plasma samples were obtained from each tortoise on the first (day 0) and last (day 35) days of the study, and concentrations of 25-hydroxyvitamin D(3) were determined. Amount of UVB radiation in enclosures was measured. Results-Mean ± SD plasma 25-hydroxyvitamin D(3) concentrations for tortoises exposed to the mercury-vapor and fluorescent lamps were significantly lower on day 35 (155.69 ± 80.71 nmol/L and 134.42 ± 51.42 nmol/L, respectively) than they were on day 0 (368.02 ± 119.34 nmol/L and 313.69 ± 109.54 nmol/L, respectively). Mean ± SD plasma 25-hydroxyvitamin D(3) concentration for tortoises exposed to sunlight did not differ significantly between days 0 (387.74 ± 114.56 nmol/L) and 35 (411.51 ± 189.75 nmol/L). Mean day 35 plasma 25-hydroxyvitamin D(3) concentration was significantly higher for tortoises exposed to sunlight versus those exposed to mercury-vapor or fluorescent lamps. Sunlight provided significantly more UVB radiation than did the mercury-vapor or fluorescent lamps. Conclusions and Clinical Relevance-Plasma 25-hydroxyvitamin D(3) concentrations differed between tortoises exposed to sunlight and those exposed to artificial UVB sources. Exposure to sunlight at a latitude similar to that of the natural geographic range is recommended for healthy and calcium-deficient tortoises.

The association between plasma 25-hydroxyvitamin D3 concentrations, C-reactive protein levels, and coronary artery atherosclerosis in postmenopausal monkeys

The aim of this study was to identify the potential relationships between plasma 25-hydroxyvitamin D(3) (25OHD(3)), C-reactive protein (CRP), coronary artery atherosclerosis (CAA), and coronary artery remodeling in monkeys consuming atherogenic diets. Female cynomolgus monkeys (n = 74) were fed a casein-lactalbumin (C/L)-based, moderately atherogenic diet for 12 months. They then consumed either a soy-based (n = 35) or C/L-based (n = 39) diet for 32 months. CRP concentrations were then determined, and monkeys underwent surgical menopause. Each diet group was then rerandomized to receive soy (n = 36) or C/L (n = 38). After 32 postmenopausal months, 25OHD(3), CRP, CAA, and coronary artery remodeling were determined. All monkeys received a woman's equivalent of 1,000 IU/day of vitamin D(3) and 1,200 mg/day of calcium throughout the study. The premenopausal and postmenopausal dietary protein sources had no effect on postmenopausal 25OHD(3) concentrations (P = 0.6). Across treatment groups, there was a statistically significant inverse relationship between 25OHD(3) concentrations and CRP at necropsy (r = -0.35, P = 0.003). A significant inverse correlation between 25OHD(3) concentration and the change in CRP from premenopause to postmenopause was observed (r = -0.32, P = 0.007). The significant associations identified between plasma 25OHD(3) and CRP remained after controlling for postmenopausal diet. Those monkeys with a greater increase in CRP also had significantly more CAA and less ability to maintain normal lumens by remodeling. Higher plasma concentrations of 25OHD(3) were associated with lower CRP. Lower CRP was associated with less coronary atherosclerosis and improved coronary artery remodeling. These findings suggest that 25OHD(3) concentrations are associated with an anti-inflammatory state and may support an association between oral vitamin D3 and cardioprotection.

Coronary artery vitamin D receptor expression and plasma concentrations of 25-hydroxyvitamin D: their association with atherosclerosis.

The aim of this study was to analyze coronary artery vitamin D receptor (VDR) expression, the plasma concentrations of 25-hydroxyvitamin D3 (25OHD3), and their relationship with coronary artery atherosclerosis. Premenopausal cynomolgus monkeys were fed atherogenic diets containing the equivalent of 1,000 IU/day of vitamin D3. Protein was derived from casein-lactalbumin (C/L, n = 10), soy protein isolate (soy, n = 10), or a combination (n = 19). After 32 months of consuming the diets, each monkey underwent surgical menopause. After 32 postmenopausal months, coronary atherosclerosis was measured in the left circumflex (LCX) artery and left anterior descending (LAD) artery. VDR expression was determined for the LAD, and 25OHD3 concentrations were assessed. Both the cross-sectional area of atherosclerotic plaques (in square millimeters) and plaque thickness (in millimeters) in the LCX as well as the LAD arteries were analyzed in these monkeys. Those with higher plasma vitamin D3 concentrations and higher VDR were compared with those with higher plasma 25OHD3 concentrations and lower VDR. Significantly smaller plaque sizes were noted with higher plasma 25OHD3 concentrations and higher VDR. For the LCX artery, there was also a significantly lower plaque size (both plaque thickness and cross-sectional area) in those with higher quantities of VDR and lower 25OHD3 concentrations versus those with lower quantities of VDR and higher plasma concentrations of 25OHD3 (P = 0.009 and P = 0.040, respectively). Cynomolgus monkeys with higher quantities of VDR have significantly less atherosclerosis than do those with lower quantities of VDR and higher plasma 25OHD3 concentrations. If these findings translate to human beings, it might explain why some individuals with higher plasma concentrations of 25OHD3 have more coronary artery atherosclerosis.

25(OH)D3and Cardiovascular Risk Factors in Female Nonhuman Primates

To determine if interindividual differences in plasma concentrations of 25-hydroxyvitamin D(3) (25(OH)D(3)) have pathophysiologic significance, we evaluated a cohort of female monkeys, seeking to identify associations with clinically relevant cardiovascular risk factors, including age, abdominal obesity (waist circumference), and high-density lipoprotein cholesterol (HDL-C). One hundred fifty-five female vervet monkeys (Chlorocebus aethiops sabaeus) aged 3-25 years consumed a typical western diet for 7-8 weeks that provided a woman's equivalent of approximately 1000 IU/day of vitamin D(3). Measurements of vitamin D(3) and HDL-C concentrations, as well as waist circumference, were obtained. Among young monkeys (aged 3-5 years), compared to older monkeys (aged 16-25 years), the mean plasma 25(OH)D(3) concentrations were 82.3±3.2 ng/mL and 58.6±2.9 ng/mL (p<0.0001), respectively. Plasma 25(OH)D(3) concentrations had a range of 19.6-142.0 ng/mL (mean±standard error [SE] 66.4±1.7 ng/mL). 25(OH)D(3) concentrations were inversely associated with age (p<0.0001) and waist circumference (p=0.016) and were positively correlated with HDL-C (p=0.01). However, when statistically controlling for age, none of these relationships remained significant. Higher plasma concentrations of 25(OH)D(3) were associated with more favorable cardiovascular risk factors, with inverse associations observed between 25(OH)D(3) and abdominal obesity, HDL-C, and age. These associations were no longer significant when controlling for age.

Short communication: The preruminant calf as a model for characterizing the effects of vitamin D status in the neonate

The objective of this study was to evaluate the feasibility of using the preruminant dairy calf as a model for evaluating effects of vitamin D status in the neonate. Because the newborn calf can be sustained during the first weeks of life solely on a fluid diet having a defined composition, has documented nutritional requirements, and is minimally affected by repeated samplings of peripheral blood, it has the potential to serve as a model for characterizing nutrient-specific effects on the growth and health of the neonate. Colostrum-fed Holstein bull calves (n=13) entered the trial at approximately 4 d of age. All calves were fed a custom-formulated milk replacer devoid of vitamin D. Plasma 25-hydroxyvitamin D3 concentrations in all calves were determined on a regular basis beginning at d 0. Using this information, low- and high-status groups of calves were established by subcutaneous administration of 25-hydroxyvitamin D3. To maintain targeted plasma 25-hydroxyvitamin D3 concentrations in low (<30 ng/mL) and high (>60 ng/mL) vitamin D–status calves, low-status calves (n=6) received a total of 8,600 IU (2,225 IU/wk) of vitamin D during the experimental period and high-status calves (n=7) received 54,000 IU (13,500 IU/wk). Concentrations of 25-hydroxyvitamin D3 in low-status calves averaged 27 ng/mL, compared with 78 ng/mL in high-status calves, and were less at all sampling times from d 7 to d 28. Concentrations of 1,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 were not correlated. Calcium, magnesium, and phosphorous concentrations were unaffected by 25-hydroxyvitamin D3 administration; however, plasma calcium and 1,25-dihydroxyvitamin D3 concentrations were correlated. Calcium and magnesium concentrations decreased with age but remained within normal ranges for dairy cattle. These results indicate that it is possible to predictably control vitamin D status over a 28-d period and suggest that the preruminant calf might be useful as a model for studying effects of vitamin D on growth, development, and immune function in the neonate.

Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D3 concentrations in corn snakes (Elaphe guttata)

To determine whether corn snakes exposed to UVB radiation have increased plasma 25-hydroxyvitamin D3 concentrations, compared with control snakes. 12 corn snakes (Elaphe guttata). After an acclimation period in individual enclosures, a blood sample was collected from each snake for assessment of plasma 25-hydroxyvitamin D3 concentration. Six snakes were provided with no supplemental lighting, and 6 snakes were exposed to light from 2 full-spectrum coil bulbs. By use of a radiometer-photometer, the UVA and UVB radiation generated by the bulbs were measured in each light-treated enclosure at 3 positions at the basking surface and at 2.54 cm (1 inch) below each bulb surface; the arithmetic mean values for the 3 positions at the basking surface and each individual bulb surface were calculated immediately after the start of the study and at weekly intervals thereafter. At the end of the study (day 28), another blood sample was collected from each snake to determine plasma 25-hydroxyvitamin D3 concentration. Mean +/- SD plasma concentration of 25-hydroxyvitamin D3 in snakes that were provided with supplemental lighting (196 +/- 16.73 nmol/L) differed significantly from the value in control snakes (57.17 +/- 15.28 nmol/L). Mean exposure to UVA or UVB did not alter during the 4-week study period, although the amount of UVA recorded near the bulb surfaces did change significantly. These findings have provided important insight into the appropriate UV radiation requirements for corn snakes. Further investigation will be needed before exact husbandry requirements can be determined.

Determination of Fat-Soluble Vitamins in Human Plasma, Breast Milk and Food Samples: Application in Nutrition Survey for Establishment of "Dietary Reference Intakes for Japanese"

Dietary habits are an important risk factor for lifestyle-related diseases. To carry out a nutrition survey of fat-soluble vitamins, we developed determination methods of fat-soluble vitamins using liquid chromatography-atmospheric pressure chemical ionization/tandem mass spectrometry or high-performance liquid chromatography with fluorescence detection. In these methods, stable isotope-labeled compounds or vitamin K analogs with a saturated side-chain were used as internal standards. These methods have high sensitivity and sufficient accuracy, and we applied them in a nutrition survey about the status of fat-soluble vitamins in Japanese women. Plasma concentrations of 25-hydroxyvitamin D3 [25(OH)D3] and 25-hydroxyvitamin D2 [25(OH)D2] in healthy postmenopausal women (n=98) were 20.5±7.9 and 0.4±1.4 ng/ml, respectively. A significant negative correlation in plasma levels between 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone was observed. For vitamin K homologs, plasma levels of phylloquinone (PK), menaquinone-4 (MK-4) and menaquinone-7 (MK-7) in Japanese women of various ages (n=1409) were 1.03±0.90, 0.12±0.28 and 6.71±13.6 ng/ml, respectively. The mean total vitamin K intake of Japanese young women was about 230 μg/day, and 94% of participants met the Adequate Intake of vitamin K for women aged 18-29 years in Japan, 60 μg/day. Moreover, we determined fat-soluble vitamins in breast milk collected from Japanese lactating women and revealed that the contents of all-trans-retinol, vitamin D3, 25(OH)D3, α-tocopherol, PK and MK-4 in breast milk were 0.39±0.14 μg/ml, 0.10±0.15 ng/ml, 0.08±0.04 ng/ml, 3.96±1.84 μg/ml, 3.56±2.19 and 1.77±0.68 ng/ml, respectively.

Dietary P regulates phosphate transporter expression, phosphatase activity, and effluent P partitioning in trout culture.

Phosphate utilization by fish is an important issue because of its critical roles in fish growth and aquatic environmental pollution. High dietary phosphorus (P) levels typically decrease the efficiency of P utilization, thereby increasing the amount of P excreted as metabolic waste in effluents emanating from rainbow trout aquaculture. In mammals, vitamin D3 is a known regulator of P utilization but in fish, its regulatory role is unclear. Moreover, the effects of dietary P and vitamin D3 on expression of enzymatic and transport systems potentially involved in phosphate utilization are little known. We therefore monitored production of effluent P, levels of plasma vitamin D3 metabolites, as well as expression of phosphatases and the sodium phosphate cotransporter (NaPi2) in trout fed semipu diets that varied in dietary P and vitamin D3 levels. Mean soluble P concentrations varied markedly with dietary P but not with vitamin D3, and constituted 40-70% of total effluent P production by trout. Particulate P concentrations accounted for 25-50% of effluent P production, but did not vary with dietary P or vitamin D3. P in settleable wastes accounted for <10% of effluent P. The stronger effect of dietary P on effluent P levels is paralleled by its striking effects on phosphatases and NaPi2. The mRNA abundance of the intestinal and renal sodium phosphate transporters increased in fish fed low dietary P; vitamin D3 had no effect. Low-P diets reduced plasma phosphate concentrations. Intracellular phytase activity increased but brushborder alkaline phosphatase activity decreased in the intestine, pyloric caeca, and gills of trout fed diets containing low dietary P. Vitamin D3 had no effect on enzyme activities. Moreover, plasma concentrations of 25-hydroxyvitamin D3 and of 1,25-dihydroxyvitamin D3 were unaffected by dietary P and vitamin D3 levels. The major regulator of P metabolism, and ultimately of levels of P in the effluent from trout culture, is dietary P.

Poult Malabsorption Syndrome. II. Pathogenesis of Skeletal Lesions

One-day-old poults were placed on litter on which poults had previously developed diarrhea, increased mortality, stunting, and malabsorption. Gross, microscopic, and morphometric evaluations of the proximal tibiotarsal growth plate, along with analysis of plasma calcium, phosphorus, and 25-hydroxyvitamin D3 concentrations, were conducted for 3 weeks to determine the development and character of skeletal lesions. Poults developed enteritis with diarrhea and dehydration. Body weights and shank lengths were significantly decreased. Plasma 25-hydroxyvitamin D3 concentrations were significantly decreased. Plasma calcium was significantly decreased on day 8. Plasma phosphorus concentrations were significantly increased on day 8 and were significantly decreased on days 15, 18, and 22. Growth plates narrowed on days 8 and 11 and expanded on days 15, 18, and 22. The proliferating-prehypertrophy zone significantly decreased in length on days 11, 18, and 22, and significantly increased in length on day 15. The unmineralized hypertrophy zone was significantly increased in length on days 15, 18, and 22. The mineralized hypertrophy zone was significantly decreased in length on all days. Skeletal lesions during the poult malabsorption syndrome evolved from an early osteoporotic lesion associated with hypocalcemia to a rachitic lesion associated with depleted vitamin D and hypophosphatemia.

Effect of vitamin D supplementation during pregnancy on the vitamin D status of ewes and their lambs.

Pregnant ewes were injected intramuscularly with 300,000 iu of vitamin D3 in a water miscible vehicle either 10, seven or four weeks before the expected lambing date and the effects on plasma concentrations of 25-hydroxyvitamin D3 were monitored. The concentrations increased quickly and remained high at parturition but at no time were they outside the normal physiological range. The concentrations in the plasma of the newborn lambs were higher than in uninjected controls and were well correlated with the concentrations in their mothers. Dosing pregnant ewes with 300,000 iu of vitamin D3 in a rapidly available form, approximately two months before lambing, provided a safe means of increasing the vitamin D status of the ewe and the newborn lamb by preventing the seasonally low concentrations of 25-hydroxyvitamin D3.

Hypophosphataemia and vitamin D metabolism in sheep.

The effect of dietary induced hypophosphataemia on vitamin D metabolism was studied in four conscious sheep. No change in the plasma concentrations of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) were found during hypophosphataemia when compared with normophosphataemia. In addition both the metabolic clearance rate and the production rate of plasma 1,25(OH)2D3 were unaltered during hypophosphataemia. This suggests that changes in circulating levels of 1,25(OH)2D3 were not necessary for the increased efficiency of intestinal phosphorus absorption seen in phosphorus-depleted hypophosphataemic sheep, and may explain why there is no increase in efficiency of intestinal calcium absorption in phosphorus depleted sheep. Increases in phosphataemia induced acutely by intravenous phosphate infusion for 3 h also had no effect on plasma 1,25(OH)2D3 concentration. It is concluded that in the sheep, unlike non-ruminant animals, chronic hypophosphataemia does not increase plasma 1,25(OH)2D3 concentrations and plays no physiological role in regulating its production or metabolism.

Vitamin D3 and D3 Metabolites in Young Goats Fed Varying Amounts of Calcium and Vitamin D3

Twenty-four male goats, 2 to 4 wk of age, were allotted to four dietary treatments in a 2×2 factorial design and, for 20 wk, were fed a milk diet at 12.5% body weight. Treatments varied in amounts of supplemental calcium and vitamin D3. Daily allowances per kilogram body weight were: 9.4 IU vitamin D3 (basal), 9.4 IU vitamin D3 plus 406mg calcium carbonate (basal plus Ca), 940 IU vitamin D3 (basal plus D3), and 940 IU vitamin D3 plus 406mg calcium carbonate (basal plus Ca plus D3). At the end of wk 7, a corn supplement was added to all diets at 1% body weight daily. Addition of vitamin D3 to the diet resulted in a dramatic increase in plasma concentrations of vitamin D3. Goats in the basal plus D3 and basal plus Ca plus D3 groups had nearly 100× greater concentrations of vitamin D3 than goats in the basal and basal plus Ca groups. When greater amounts of vitamin D3 were fed, dietary calcium interacted to decrease plasma vitamin D3 concentrations. Plasma concentrations of 25-hydroxyvitamin D3 were unaffected by additional dietary calcium but were increased by dietary vitamin D3, increasing sixfold to seven-fold in the basal plus D3 and basal plus Ca plus D3 groups. Supplemental calcium resulted in decreased plasma 1,25-dihydroxyvitamin D3. No signs of vitamin D toxicity were noted. The physiological responses reported implicate the goat as a potential animal model for vitamin D research in dairy cattle.

Effect of parenteral vitamin D3 on plasma 25-hydroxyvitamin D3 concentration in sheep

Vitamin D3 ranging in total amount from 10(5) iu (2.5 mg) to 9 X 10(5) iu (22.5 mg) was given intramuscularly either as a single injection or in three aliquots at three-weekly intervals to housed nonpregnant ewes on a vitamin D deficient diet. The effects on plasma concentrations of 25-hydroxyvitamin D3 (25-OHD3), the major metabolite of vitamin D, were monitored. The increase in plasma 25-OHD3 showed a large variation between animals and was related to, but not proportional to, the dose. None of the treatments produced 25-OHD3 concentrations greater than those in grazing sheep in summer. Repeated dosing provided for more efficient use of the injected vitamin D3.