Adrenocorticotropin Hormone (ACTH)

ACTH is a critical stress hormone released by the anterior pituitary and acting on the adrenal glands.

 

 

Function

 

ACTH travels through the blood to the adrenal cortex, where it induces expression of hormones called glucocorticoids, including cortisol

 

 

Regulation of Expression

 

CRH causes ACTH release from corticotrophs in the anterior pituitary. ACTH release is mediated by a GPCR and Ca2+ influx.

 

Cortisol provides negative feedback to the hypothalamus and pituitary.

 

Consequences of Overexpression

Overexpression of PRL (hyperprolactinemia) can lead to galactorrhea

 

Consequences of Underexpression

 

 

Signalling Pathways

Both PRL and GH have similiar affinities for the PRL receptor.

 

Structure

Prolactin is a 199 amino acid hormone with 16% homology to growth hormone.