Studies of the Porcine Intestinal Calcitriol Receptor in Pseudo-Vitamin D Deficiency Rickets Type I

1990 ◽  
Vol 79 (4) ◽  
pp. 409-414 ◽  
Author(s):  
B. Schröder ◽  
R. Kaune ◽  
J. Harmeyer

1. Calcitriol (1,25-dihydroxyvitamin D3) concentrations in plasma of humans and pigs with pseudo-vitamin D deficiency rickets type I (PVDRI) have been reported to be significantly lower than in normal subjects and animals. Sometimes, however, calcitriol concentrations are relatively high in these subjects and animals (50–80 pmol/l) and nevertheless clinical symptoms of rickets develop. We have studied whether or not the development of rachitic lesions in piglets with PVDRI is due to altered binding properties of the intestinal calcitriol receptor in addition to the defective renal production of calcitriol. PVDRI piglets with clinical and biochemical symptoms of rickets (hypocalcaemia, increased activity of alkaline phosphatase) and with calcitriol concentrations in plasma of 83.7 ± 4.2 pmol/l (n = 7) were used. They were compared with unaffected piglets with normal calcitriol concentrations (178.0 ± 17.7 pmol/l, n = 9). 2. The equilibrium dissociation constant (Kd) of the receptor in the PVDRI piglets (0.31 ± 0.05 nmol/l) and in control piglets (0.33 ± 0.05 nmol/l) and the maximum binding capacity (Bmax.) (674 ± 103 and 719 ± 122 fmol/mg of protein, respectively) were not different (n = 9). 3. The association rate constant (kass) at 4°C [0.15 × 107 and 0.24 × 107 (mol/l)−1 min−1] and the dissociation rate constant (kdiss) (0.40 × 10−3 and 0.48 × 10−3 min−1; half-life of dissociation = 24.1 and 28.9 h, respectively) were also not different between diseased and control piglets. 4. No differences between PVDRI and control piglets were also found for the relative molecular mass (47 500 and 47700, respectively) and the Stokes' radius (3.04 and 3.05 nm, respectively) of the calcitriol receptor. 5. It is concluded that the intestinal calcitriol receptor of this animal model functions normally and that changes in binding properties and concentration of the intestinal calcitriol receptor do not contribute to the development of rachitic lesions in PVDRI piglets.

1987 ◽  
Vol 115 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Reinhard Kaune ◽  
Johein Harmeyer

Abstract. Vitamin D metabolism was studied in the 'Hannover Pig', a strain which suffers from pseudo vitamin D-deficiency rickets, type I. Animals of this strain are known to be devoid of renal 25-hydroxyvitamin D3-1α-hydroxylase and -24-hydroxylase activities. Pigs with florid rickets and hypocalcaemia were treated with single im injections of 0.25 to 1.25 mg of vitamin D3, doses that have been shown in previous studies to be effective in producing transient healing of rachitic symptoms. The levels of vitamin D3 and its most relevant physiological metabolites in plasma were estimated at intervals before and after this vitamin D3 treatment. Vitamin D3 rose from 14.8 ± 8.1 to 364 ± 190 nmol/l (mean ± sd) 2 to 3 days post injectionem, 25-hydroxyvitamin D3 from 131.0 ± 46.2 to 1068 ± 160 nmol/l within 7 days post injectionem. The 1α,25-dihydroxyvitamin D3 concentration in plasma was elevated from 73.9 ± 25.0 to 281 ± 168 pmol/l 2 to 3 days post injectionem and declined continually from that time. 24R,25-dihydroxyvitamin D3 and 25S,26-dihydroxyvitamin D3 levels after treatment showed different responses in different animals being either elevated or unchanged. Clinical healing of the pigs with these doses of vitamin D3 was attributed to the transient rise of 1α,25-dihydroxyvitamin D3 in plasma. It was assumed that 1α,25-dihydroxyvitamin D3 synthesis takes place under these circumstances in extrarenal tissues.


Bone ◽  
2020 ◽  
Vol 136 ◽  
pp. 115322
Author(s):  
Elizabeth L. Lin ◽  
Gary S. Gottesman ◽  
William H. McAlister ◽  
Vinieth N. Bijanki ◽  
Karen E. Mack ◽  
...  

2000 ◽  
Vol 21 (9) ◽  
pp. 296-302
Author(s):  
Terence A. Joiner ◽  
Carol Foster ◽  
Thomas Shope

1975 ◽  
Vol 3 (2) ◽  
pp. 105-110 ◽  
Author(s):  
W. H. Opie ◽  
C. J. B. Muller ◽  
H. Kamfer

2022 ◽  
Vol 4 (1) ◽  
Author(s):  
Omar M. E. Ali

Abstract Fibromyalgia is a debilitating chronic condition which poses a therapeutic challenge to the clinician. With a large backlog in patient flow subsequent to the COVID-19 pandemic and rising numbers of patients with post-acute sequelae of COVID-19 (PASC) presenting with fibromyalgia-like clinical features, there is an increasingly pressing need to identify broad cost-effective interventions. Low levels of vitamin D have previously been reported in patients with fibromyalgia, though any causative link has been difficult to establish. A systematic literature review on the association between vitamin D deficiency and fibromyalgia was performed examining retrospective evidence both for and against an association between vitamin D deficiency (VDD) and fibromyalgia and evaluating the therapeutic benefit from supplementation. A group of six studies were selected based on relevance, use of controls, quality of research and citations. Four primary studies assessing the prevalence of VDD in fibromyalgia patients versus controls were evaluated with a total 3,496 subjects. Three included females only and one larger study assessed males. Two (n = 313) concluded the presence of a statistically significant association, and two (n = 161) found none. Two randomised controlled trials assessing the effect of vitamin D supplementation in a total of 80 subjects found conflicting results, with pain reduction in one and none in the other. It is likely there exists an association between VDD deficiency and fibromyalgia in a large subset of patients, although establishing primary causation is difficult. There is a need for larger randomised controlled trial designs with more effective comparison with healthy subjects and control for confounding factors. Given VDD is a major problem in the general population, we recommend supplementation be recommended by healthcare professionals to fibromyalgia patients for the purpose of maintaining bone health given their potentially increased susceptibility to developing deficiency and its sequelae.


2020 ◽  
Author(s):  
Mostafa Qorbani ◽  
Motahar Heidari-Beni ◽  
Hanieh-Sadat Ejtahed ◽  
Gita Shafiee ◽  
Farid Goodarzi ◽  
...  

Abstract Background: Metabolic syndrome (MetS) starts from early life, and is one of the important underlying factors for non-communicable disease (NCDs) in adulthood. Controversial evidence exists on the role of vitamin D deficiency in increasing risk of pediatric MetS. Objective: This study aimed to assess the relationship between vitamin D level with MetS and its components in children and adolescents. Methods: This cross-sectional nationwide study was performed as part of a surveillance program in Iran. Participants were 2596 students, aged 7 to 18 years, living in 30 provinces. In addition to filling questionnaires, physical examination was conducted, and blood samples were collected. Serum concentration of 25-hydroxy vitamin D (25(OH)D) was measured using direct competitive immunoassay chemiluminescene method.Results: 2596 students with mean age of 12.2 y (55.1% boys) were recruited. Prevalence of vitamin D deficiency and insufficiency in participants was 10.6% (n=276), and 60.5% (n=1570), respectively. Prevalence of MetS was higher in vitamin D deficient group. Students with deficient vitamin D level had higher odds of MetS (OR: 4.25, 95%CI: 2.26-7.98), abdominal obesity (OR: 2.24, 95%CI: 1.61-3.12), low HDL-C (OR: 1.65, 95%CI: 1.18-2.30) and high fasting blood sugar (OR: 2.56, 95%CI: 1.43-4.57) in comparison to those with sufficient level of vitamin D.Conclusion: Vitamin D deficiency was associated with increased odds of MetS and its components in Iranian pediatric population. These findings underscore the importance of prevention and control of vitamin D deficiency in preventative programs against NCDs.


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