Vitamin D metabolism in a frugivorous nocturnal mammal, the Egyptian fruit bat

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Vitamin D metabolism in a frugivorous nocturnal mammal, the

Egyptian fruit bat (Rousettus aegyptiacus).

Cavaleros M, Buffenstein R, Ross FP, Pettifor JM.

Department of Paediatrics, University of the Witwatersrand,

Johannesburg,7 York Road, 2193, South Africa.

The nocturnal, frugivorous Egyptian fruit bat (Rousettus

aegyptiacus) has no obvious access to either endogenous or dietary

sources of vitamin D. We hypothesized that this species under natural

conditions would be vitamin D deficient and that both serum mineral

concentrations and vitamin D metabolite concentrations would be low.

Both wild populations and captive populations appear to have an

impoverished vitamin D status, as concentrations of the principle

circulating metabolite, 25-hydroxyvitamin D [25(OH)D] are undetectable

(<4 ng/mL) and those of the active metabolite, 1,25-dihydroxyvitamin D

[1,25(OH)(2)D] are low. Intraperitoneal administration of labelled

25(OH)D revealed enhanced 1 alpha-hydroxylase activity confirming a

natural state of vitamin D deficiency. This may account for the

undetectable levels of 25(OH)D; for limited amounts of the prohormone

substrate are rapidly converted to the active hormone. Both vitamin

D(2) and D(3) metabolites were detected in bat serum, albeit in very

small amounts, inferring that in their natural habitat fruit bats may

have limited access to both exogenous dietary sources and endogenous

sources. Despite the low levels of vitamin D metabolites in

wild-caught and captive D-unsupplemented individuals, serum mineral

concentrations were well regulated and similar to those of bats

receiving D-supplements, with no pathological problems associated with

vitamin D deficiency evident.

Publication Types:

* Research Support, Non-U.S. Gov't

MeSH Terms:

* Alkaline Phosphatase/blood

* Animals

* Chiroptera/blood

* Chiroptera/metabolism*

* Cholecalciferol/metabolism

* Chromatography, Affinity

* Chromatography, Gel

* Ergocalciferols/metabolism

* Minerals/blood

* Osmolar Concentration

* Vitamin D/analogs & derivatives*

* Vitamin D/blood

* Vitamin D/metabolism*

* Vitamin D-Binding Protein/blood

Substances:

* Ergocalciferols

* Minerals

* Vitamin D-Binding Protein

* Vitamin D

* 25-hydroxyvitamin D

* 1,25-dihydroxyvitamin D

* Cholecalciferol

* Alkaline Phosphatase

PMID: 12899852 [PubMed - indexed for MEDLINE]