Interpretation of isolated agenesis of the pituitary.

Cholesterol synthesis inhibitors administered to rats caused more or less complete forms of the holoprosencephalic syndrome, consisting of severe abnormalities of the brain, sense organs and pituitary. The absence of the pituitary was also observed in fetuses without externally visible cephalic abnormalities. These observations suggest that the isolated absence of the pituitary is the lesser form of the holoprosencephalic syndrome. This interpretation is also valid for cases of isolated absence of the pituitary observed in humans.