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Effect of age, gonadectomy and hypophysectomy on mitochondrial hydroxylation of vitamin D3 (cholecalciferol) and of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol in female and male rat liver.

ABSTRACT: In a previous study we found that liver mitochondrial side-chain hydroxylation of vitamin D3 (cholecalciferol) and of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol was higher in female than in male rats [Saarem & Pedersen (1987) Biochem. J. 247, 73-78]. The present paper describes the effects of age, gonadectomy and hypophysectomy on these activities. The sex difference became manifest above the age of 7 weeks. Ovariectomy and/or injection of oestradiol valerate had no effect on the hydroxylase activities in adult females. Castration increased, and subsequent testosterone treatment decreased, the hydroxylase activities in adult males. Hypophysectomy had no effect in females, but increased the hydroxylase activities in males. Testosterone treatment had no effect in hypophysectomized females or males. Injection of oestradiol valerate had no effect on the hydroxylase activities in hypophysectomized females. In hypophysectomized males this treatment had no effect on the vitamin D3 25-hydroxylase activity, but decreased the C27-steroid 27-hydroxylase activity in males. Microsomal 1 alpha-hydroxyvitamin D3 25-hydroxylase activity was lower in females than in males in all age groups. Castration or hypophysectomy decreased the activity in male rats. It is concluded that, in adult female rats, the mitochondrial side-chain hydroxylation of vitamin D3 and of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol is independent of sex hormones. In males these activities are regulated by influence of sex hormones on the hypophysis, probably by the presence of androgens in the neonatal period. Different effects on the two hydroxylases indicate the presence of at least two different cytochromes P-450 in rat liver mitochondria.

SUBMITTER: Saarem K

PROVIDER: S-EPMC1149027 | biostudies-other | 1988 Apr

REPOSITORIES: biostudies-other

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Project description:AIM:To prospectively evaluate the effects of vitamin D3 on disease activity and quality of life in ulcerative colitis (UC) patients with hypovitaminosis D. METHODS:The study was a prospective double-blinded, randomized trial conducted at Community Regional Medical Center, Fresno, CA from 2012-2013. Patients with UC and a serum 25(OH)D level <30 ng/ml were eligible for the study. Enrolled subjects were randomized to receive either 2,000 IU or 4,000 IU of oral vitamin D3 daily for a total of 90 days. The Short IBD Questionnaire (SIBDQ) for quality of life, the Partial Mayo Score for UC disease activity and serum lab tests were compared between the two treatment groups. Matched pair t-tests were computed to assess differences between the vitamin D levels, CRP, UC disease activity and SIBDQ scores before and after vitamin D3 therapy using SPSS version 21. RESULTS:Eight UC patients received 2,000 IU/daily and ten UC patients received 4,000 IU/daily of vitamin D3 for 90 days. Vitamin D levels increased after 90 days of oral vitamin D3 in both dose groups. However, the increase in vitamin D levels after 90 days of oral vitamin D3, in the 4,000 IU group was significantly higher 16.80 ± 9.15 (p < 0.001) compared to the 2,000 IU group of vitamin D 5.00 ± 3.12 (p = 0.008). Normal vitamin D levels (>30 ng/dl) were achieved in four out of the ten UC patients (40%) in the 4,000 IU group and in one out of the eight UC patients (12%) in the 2,000 IU group. In the group receiving 4,000 IU/day of vitamin D3 the increase in quality life scores (SIBDQ) was significant 1.0 ± 1.0 (p = 0.017) but not in the 2,000 IU vitamin D3 group 0.1 ± 1.0 (p = 0.87). In the 2,000 IU of vitamin D3 group the mean decrease in the Partial Mayo UC Score was -0.5 ± 1.5 (p = 0.38) compared to -1.3 ± 2.9 (p = 0.19) in the 4,000 IU vitamin D3 group but this was not statistically significant. CRP levels decreased after 90 days of daily vitamin D3 in both the 2,000 IU group and 4,000 IU group by -3.0 ± 9.4 (p = 0.4) and -10.8 ± 35.0 (p = 0.36) respectively. CONCLUSION:Vitamin D3 at 4,000 IU/day is more effective than 2,000 IU/day in increasing vitamin D to sufficient levels in UC patients with hypovitaminosis D, however higher doses or treatment beyond ninety days may be required. Vitamin D3 may improve the quality of life in UC patients but clinically significant improvement is not yet established. The effect of vitamin D3 on UC disease activity is still unclear. Further larger studies are needed to investigate the effects of vitamin D in ulcerative colitis.

Project description:Elevated concentrations of fibroblast growth factor 23 (FGF23) are postulated to promote 25-hydroxyvitamin D (25[OH]D) insufficiency in CKD by stimulating 24-hydroxylation of this metabolite, leading to its subsequent degradation; however, prospective human studies testing this relationship are lacking.An open-label prospective study was conducted from October 2010 through July 2012 to compare the effect of 8 weeks of oral cholecalciferol therapy (50,000 IU twice weekly) on the production of 24,25(OH)2D3 in vitamin D-insufficient patients with CKD (n=15) and controls with normal kidney function (n=15). Vitamin D metabolites were comprehensively profiled at baseline and after treatment, along with FGF23 and other mineral metabolism parameters.Vitamin D3 and 25(OH)D3 concentrations increased equivalently in the CKD and control groups following cholecalciferol treatment (median D3 change, 8.6 ng/ml [interquartile range, 3.9-25.6 ng/ml] for controls versus 12.6 ng/ml [6.9-41.2 ng/ml] for CKD [P=0.15]; 25(OH)D3 change, 39.2 ng/ml [30.9-47.2 ng/ml] for controls versus 39.9 ng/ml [31.5-44.1 ng/ml] for CKD [P=0.58]). Likewise, the absolute increase in 1?,25(OH)2D3 was similar between CKD participants and controls (change, 111.2 pg/ml [64.3-141.6 pg/ml] for controls versus 101.1 pg/ml [74.2-123.1 pg/ml] for CKD; P=0.38). Baseline and post-treatment 24,25(OH)2D3 concentrations were lower in the CKD group; moreover, the absolute increase in 24,25(OH)2D3 after therapy was markedly smaller in patients with CKD (change, 2.8 ng/ml [2.3-3.5 ng/ml] for controls versus 1.2 ng/ml [0.6-1.9 ng/ml] for patients with CKD; P<0.001). Furthermore, higher baseline FGF23 concentrations were associated with smaller increments in 24,25(OH)2D3 for individuals with CKD; this association was negated after adjustment for eGFR by multivariate analysis.Patients with CKD exhibit an altered ability to increase serum 24,25(OH)2D3 after cholecalciferol therapy, suggesting decreased 24-hydroxylase activity in CKD. The observed relationship between baseline FGF23 and increments in 24,25(OH)2D3 further refutes the idea that FGF23 directly contributes to 25(OH)D insufficiency in CKD through stimulation of 24-hydroxylase activity.

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Effect of age, gonadectomy and hypophysectomy on mitochondrial hydroxylation of vitamin D3 (cholecalciferol) and of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol in female and male rat liver.

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