These hormones are either amino-acid based and water soluble, or steroidal and lipid-soluble, and may target many types of cells or just turn on specific ones.

这些荷尔是基于氨基酸的水溶性荷尔，是甾体和脂溶性荷尔，可能针对多种类型的细胞，或者只是针对特定的细胞。

Vitamin D is absorbed into our bloodstream and converted to the active form (a secosteroidal hormone) and a storage form (25-hydroxyvitamin D) – it functions more like a hormone than a vitamin.

维生素 D 被血液吸收，并转化为活性形式（一种开环甾体激素）和储存形式（25-羟基维生素 D）——其功能更像是一种激素而不是维生素。