Final answer:
The pars intermedia of the pituitary gland is distinct in fetal life but becomes less distinct after birth, eventually merging with the anterior pituitary.
Step-by-step explanation:
The component of the pituitary gland that exists during fetal life and becomes less distinct during extrauterine life is the pars intermedia. In the developing fetus, the pars intermedia is situated between the pars distalis and the posterior lobe of the pituitary gland. Postnatally, it diminishes in distinctness, and in adult humans, it merges with the anterior pituitary, making it often difficult to discern.