GI hormones vs secretin

GI hormones and secretin both are nouns.

Word	Noun	Adjective	Verb	Adverb
GI hormones	Yes	No	No	No
secretin	Yes	No	No	No

As nouns, secretin is a hyponym of GI hormones; that is, secretin is a word with a more specific, narrower meaning than GI hormones:

GI hormones: hormones that affect gastrointestinal functioning
secretin: a gastrointestinal hormone that stimulates the secretion of water and bicarbonate from the pancreas and bile ducts whenever the stomach empties too much acid into the small intestine

Other hyponyms of GI hormones include gastrin, cholecystokinin, ghrelin, motilin.

GI hormones (noun)	secretin (noun)
hormones that affect gastrointestinal functioning	a gastrointestinal hormone that stimulates the secretion of water and bicarbonate from the pancreas and bile ducts whenever the stomach empties too much acid into the small intestine