studies have proposed a role of vitamin D in adipogenesis. Here, we
sought to study the impact of the vitamin D receptor (Vdr) on adipocyte size in young and old mice and the effect of maternal vitamin D deficiency on fetal adipogenesis.
Methods and results
Histological analysis of adipose tissues shows that Vdr knockout (KO) mice have smaller adipocytes than wild-type (WT) mice. Next, we compare young and old Vdr-KO and WT mice and find no differences in adipocyte sizes between weaned Vdr-KO and WT mice. However, 1-year-old Vdr-KO
mice, suffering from alopecia, have smaller-sized adipocytes than WT
mice, although they consume more food. To elucidate whether vitamin D
can directly impact adipocyte development at a critical stage of
adipogenesis, we feed rat dams a vitamin D deficient (0 IU kg−1) or vitamin D adequate (1000 IU kg−1)
diet. Neither DNA microarray analysis of the adipose tissues of the
newborn rats nor the adipocyte sizes of 21-day-old offspring show
significant differences between the two groups.
indicate that vitamin D does not play a fundamental role in
adipogenesis because vitamin D does not affect fetal adipogenesis.
Moreover, the smaller adipocytes observed in adult Vdr-KO mice are presumably caused by an increased energy expenditure due to alopecia.