What is "cyclopamine"

n. A naturally-occurring alkaloid that belongs to the group of steroidal jerveratrum alkaloids and has the molecular formula C₂₇H₄₁NO₂

Cyclopamine (11-deoxojervine) is a naturally occurring chemical that belongs to the group of steroidal jerveratrum alkaloids. It is a teratogen isolated from the corn lily ( Veratrum californicum) that causes usually fatal birth defects. It can prevent the fetal brain from dividing into two lobes ( holoprosencephaly) and cause the development of a single eye ( cyclopia). It does so by inhibiting the hedgehog signaling pathway (Hh). Cyclopamine is useful in studying the role of Hh in normal development, and as a potential treatment for certain cancers in which Hh is overexpressed.

Cyclopamine was named for one-eyed lambs which were born to sheep which grazed on wild corn lily at a farm in Idaho. In 1957 the US Department of Agriculture started an eleven-year investigation which led to the identification of cyclopamine as the cause of the birth defect.