Regulation of 1 and 24 hydroxylation of vitamin D metabolites in the proximal tubule.
Level 5 - mechanism / opinion, no new human data
Narrative review describing biochemical and hormonal mechanisms without primary empirical human data.
PubMed 35482362 · doi:10.1177/15353702221091982
What was done
This narrative review summarizes the molecular mechanisms regulating the transcription of renal proximal tubule enzymes CYP27B1 (1-α-hydroxylase, synthesizing calcitriol) and CYP24A1 (24-hydroxylase, deactivating vitamin D metabolites) in response to classic phosphocalciotropic hormones (PTH, FGF23, calcitriol, calcitonin) and extracellular calcium and phosphate.
What was found
The abstract describes regulatory directions without reporting quantitative effect sizes or numbers: parathyroid hormone increases CYP27B1; calcitriol suppresses CYP27B1 and increases CYP24A1; FGF23 decreases CYP27B1 and increases CYP24A1; calcitonin increases CYP27B1 while having mixed effects on CYP24A1; and plasma calcium and phosphate exert mixed direct regulatory actions.
Why it matters
The review outlines how the kidney balances active vitamin D production and degradation to maintain systemic calcium and phosphate homeostasis in response to endocrine and ionic cues.
Limits
The abstract describes a narrative mechanistic review and provides no primary empirical data, quantitative measurements, or systematic search methodology.
Cited by
- supports The final stage of converting vitamin D into its active form requires functioning kidneys.
- supports A substantial portion of active vitamin D is synthesized by the kidneys.