title: Dietary regulation of digestive enzyme levels in the water snake, Natrix tessellata.
abstract: Levels of digestive enzymes were analyzed in water snakes following artificial feeding. A prominent increase of total proteolytic activity in the stomach was evident after feeding with a casein solution or after the snake was offered a fish (9- and 6-fold that of the fasting level, respectively). The activity following feeding with starch was much lower. Increased levels of chymotrypsin(ogen) as well as of amylase were evident in the pancreas 1 day after feeding the snake with fish. A specific induction of increased level of chymotrypsin in the pancreas of adult snakes was achieved by feeding with casein (12-fold that of the fasting level). In the group fed with starch, the chymotrypsin level dropped, while a 3-fold increase of amylase was evident. In newborn snakes, fed for the first time, casein induced a dramatic increase in the level of chymotrypsin in the pancreas (58 times the fasting level); feeding with starch induced an approximate 2-fold increase of chymotrypsin. Histological examination of the pancreas 1 day following casein feeding showed acinar cells loaded with zymogen granules. In starved animals and in snakes fed with starch, a much lower concentration of zymogen granules was observed. The pancreas of the snake may, thus, be most suitable for studying the specific induction of synthesis of digestive enzymes.
mesh_terms: D000064:Acclimatization; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D002918:Chymotrypsin / Q000096:biosynthesis*; D004032:Diet; D004790:Enzyme Induction; D006651:Histocytochemistry; D007700:Kinetics; D010179:Pancreas / Q000166:cytology / Q000201:enzymology*; D012911:Snakes / Q000378:metabolism*; D013270:Stomach / Q000201:enzymology*
chemical_list: D000681:Amylases; D002918:Chymotrypsin