Neonatal and maternal prostaglandin in the ontogenic response of rat gastric mucosa to H+

We have previously demonstrated that neonatal rat stomach is less susceptible to luminal H+ when compared with the adult. In the present study we investigate the role of endogenous prostaglandins (PG) in the ontogeny of gastric permeability responses to H+. Responses to luminal instillation of 250 mN HCl were measured in rats at 10, 15, 20, and 25 days after birth. Mucosal responses were measured in terms of loss of H+ and appearance of Na+, K+, and protein in the luminal instillate. Indomethacin (IM; 8 mg/kg sc) administration to rat pups reduced mucosal levels of prostaglandin E2 (PGE2) and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha). In response to intraluminal HCl, the reduction of mucosal PG did not significantly affect transmucosal fluxes of ions and protein when compared with control pups. IM was also given to lactating dams on days just prior to the pups being 10, 15, 20, and 25 days old. IM treatment significantly reduced the content of PGE2 and 6-keto-PGF1 alpha in maternal milk. Permeability responses in pups from IM-treated dams were increased over pups from control dams. This effect was not observed in 25-day-old rats. Treatment of pups from IM-injected dams with PGE2 but not PGI2 partially restored the permeability responses to luminal H+ to levels observed in pups from control dams.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effect of maternal sialoadenectomy on ontogenic response of rat gastric mucosa to luminal H+

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1993.265.2.g354 ◽

1993 ◽

Vol 265 (2) ◽

pp. G354-G360 ◽

Cited By ~ 1

Author(s):

B. L. Tepperman ◽

B. L. Vozzolo ◽

B. D. Soper

Keyword(s):

Gastric Mucosa ◽

Neonatal Rat ◽

Mucosal Permeability ◽

Maternal Milk ◽

Elution Pattern ◽

Rat Pups ◽

Rat Gastric Mucosa ◽

Epidermal Growth ◽

Old Rats ◽

Chromatographic Elution

Epidermal growth factor (EGF) originating from salivary glands has been shown to affect the development and integrity of rodent gastrointestinal mucosa. Because newborn rats receive EGF from maternal milk, we have examined the effect of sialoadenectomy as a method of depleting EGF in milk on the resistance of neonatal rat mucosa to luminal H+. Rat dams were sialoadenectomized (SALX) or sham operated 5 days after parturition. Experiments were performed on newborns 10-22 days old. Mucosal permeability responses to intraluminal HCl (300 mM) were examined in terms of luminal appearances of Na+, K+, and protein and H+ loss. EGF levels in maternal milk were determined by immunoassay. In rat pups from control litters, luminal HCl resulted in an age-associated increase in cation and protein flux across the gastric mucosa. Luminal cation and protein fluxes observed in 10- to 18-day-old rat pups from SALX dams were not significantly different from similarly aged rats from control dams. However, in 19- to 22-day-old rats from SALX dams, the permeability responses to luminal HCl were exacerbated compared with similarly aged neonates from control dams. These responses were reduced by treatment with EGF. EGF levels in milk from sham-operated and SALX dams were not significantly different in the 10- to 16-day lactational period. However, in SALX dams EGF was significantly reduced at 19 and 22 days. Chromatographic elution pattern of milk EGF was dissimilar to the pattern exhibited by submandibular gland EGF.(ABSTRACT TRUNCATED AT 250 WORDS)

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