Related Experiment Video
Updated: May 22, 2026
A Semi-Automated and Reproducible Biological-Based Method to Quantify Calcium Deposition In Vitro
Published on: June 2, 2022
No change in calcium absorption in adult Pakistani population before and after vitamin D administration using
A H Khan1, D K Rohra, S A Saghir
1Department of Pathology and Microbiology, Aga Khan University, Stadium Road, Karachi, Pakistan. aysha.habib@aku.edu
Unlabelled:
Vitamin D, parathyroid hormone levels and calcium absorption was assessed before and after cholecalciferol using Strontium as a surrogate. Increase in 25OHD, lowering of iPTH with no effect on Sr absorption was seen, suggesting the possibility that maximal Ca absorption had already been achieved in these volunteers.
Introduction:
This paper discusses the determination of calcium (Ca) absorption, using strontium (Sr) as a surrogate, before and after a single IM injection of vitamin D(3) (600,000 IU).
Methods:
Baseline serum 25-hydroxyvitamin D (25OHD), Sr, Ca, P, and intact parathyroid hormone (iPTH) were determined in 53 fasting volunteers, followed by administrating (PO) 0.03 mM (4.8 mg/kg) SrCl(2) and collecting blood at 0.5, 1 and 4 h to determine the absorption (AUC(0 → t )) of Sr. Following the initial absorption test, volunteers received a single IM injection of 600,000 IU vitamin D(3). Two months later, the fasting serum and the Sr absorption test were repeated, as described above.
Results:
The IM injection of vitamin D(3) caused a significant increase in fasting 25OHD (from 43.5 ± 19 to 66.1 ± 19.1 nmol/L (p < 0.001)) and a trend toward lower serum iPTH (from 59.8 ± 27.8 to 53 ± 31 ng/L). Fasting serum Ca and P remained unchanged. A higher 25OHD level failed (p = 0.32) to translate into a higher rate of Sr absorption. AUC(0 → 4 h) were almost identical before and after the IM injection of vitamin D(3).
Conclusion:
A single vitamin D(3) injection of 600,000 IU significantly increase mean 25OHD concentration and tended to lower iPTH concentrations in volunteers with initially low 25OHD status, suggesting to utilize this simple form of treatment to improve vitamin D status and to have a possible biological effect on Ca homeostasis. However, we found no obvious effect on Sr absorption, suggesting the possibility that maximal vitamin D-dependent Ca absorption had already been achieved in these volunteers at a lower vitamin D status.
Related Concept Videos
01:21Skeleton and Calcium Homeostasis
01:17Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
01:23Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
01:25Role of Vitamins in Maintaining Bone Health
Vitamin A
Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.
Vitamin B12
Vitamin B12 acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B12 plays a role...
01:20Study Designs in Epidemiology
Observational studies are those where the researcher does not intervene but rather observes natural variations. They include cross-sectional, cohort, and case-control studies.
01:25Imaging Studies for Cardiovascular System VI: Calcium -Scoring CT