Somatotroph
A growth hormone-producing cell in the anterior pituitary gland, comprising approximately 50% of pituitary cells. Somatotrophs are stimulated by GHRH and inhibited by somatostatin. GHRH analogues target somatotrophs to boost GH production, while somatostatin analogues suppress them.
Technical Context
Somatotrophs constitute approximately 50% of anterior pituitary cells and are located mainly in the lateral wings of the gland. They contain secretory granules (300-600nm diameter) storing GH that is released in bursts upon GHRH receptor (GHRHR) activation. GHRHR is a Gαs-coupled GPCR that increases intracellular cAMP → PKA → GH gene transcription and granule exocytosis. Somatostatin receptors (mainly SSTR2 and SSTR5) are also expressed on somatotrophs — their activation (Gαi-coupled, decreasing cAMP) inhibits GH release. The ghrelin receptor (GHS-R1a) provides a third regulatory input. Somatotroph adenomas cause acromegaly; their high expression of SSTR2 explains the effectiveness of octreotide and lanreotide.