( ( When ( proteins ( enter ( the stomach ) ) ) ) ( , ( ( ( a ( peptide hormone ) ) ( known ( as gastrin ) ) ) ( ( is ( ( ( secreted ( from ( the ( gastric mucosa ) ) ) ) , ) ( stimulating ( ( the secretion ) ( of ( gastric fluid ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS proteins)) (VP (VBP enter) (NP (DT the) (NN stomach))))) (, ,) (NP (NP (DT a) (JJ peptide) (NN hormone)) (VP (VBN known) (PP (IN as) (NP (NN gastrin))))) (VP (VBZ is) (VP (VBN secreted) (PP (IN from) (NP (DT the) (JJ gastric) (NN mucosa))) (, ,) (S (VP (VBG stimulating) (NP (NP (DT the) (NN secretion)) (PP (IN of) (NP (JJ gastric) (NN fluid)))))))) (. .)))
When proteins enter the stomach, a peptide hormone known as gastrin is secreted from the gastric mucosa, stimulating the secretion of gastric fluid .
(ROOT (S (NP (NNP Gastrin)) (VP (VBZ signals) (NP (NP (DT the) (NN secretion)) (PP (IN of) (NP (JJ gastric) (NN acid))))) (. .)))