TABLE 5

Ontogeny of oral cavity and gastric digestive enzymes

EnzymeHumanRatPigOther
Lingual lipaseDetected by GW 26 and detected at  birth with subsequent decline  (Hamosh et al., 1981; Fredrikzon  et al., 1982; Smith et al., 1986;  Lee et al., 1993)Primary source of lipase activity at  birth; mouse is similar (Henning,  1981; DeNigris et al., 1988)Not specifically describedFor neonatal guinea pigs, rabbits and  baboons, low or no activity  detected (DeNigris et al., 1988)
Salivary amylaseLow levels present prenatally and at  birth; adult levels achieved by  3 mo of age (Sevenhuysen et al.,  1984; Shibata et al., 2013;  García-Blanco et al., 2016)Not detected until second postnatal  week, with substantial increase at  weaning (Redman and Sreebny,  1971)Not specifically describedNot specifically described for other  species used for nonclinical drug  development
Gastric lipaseDetected by GW 26 and primary  source of lipase activity at birth  for term and preterm infants;  subsequent decline postnatally  (Sarles et al., 1992; Ménard et al.,  1995; Armand et al., 1996)Negligible activity at birth for both  rats and mice (DeNigris et al.,  1988)Highest in neonatal period  then declines after  weaning (Li et al., 2001)Primary source of lipase activity in  neonates of most nonrodent  species (pig, dog, rabbit, guinea  pig, baboon) (DeNigris et al.,  1988; Iverson et al., 1991; Carrière  et al., 1992)
Gastric pepsinPresent and active at birth; but lower  expression and activity than  adults; activity increases after  initiation of oral feeding (Wagner,  1961; Agunod et al., 1969;  DiPalma et al., 1991; Armand  et al., 1996)Not detected until second postnatal  week, then activity increases  through weaning (Deren, 1971;  Furihata et al., 1972; Henning,  1981)Low at birth but gradual  increase after 1st week  postnatal (Cranwell, 1985),  and substantial increase at  3 wk (Cranwell, 1985; Smith,  1988)In ferrets, low at birth with gradual  rise during first 3 wk postnatal  (Hamosh et al., 1998); in rabbits  and dogs, low or no activity until  ∼3 wk (Buddington et al., 2003)