It has been suggested that parasite excretory/secretory (ES) products may be capable of direct stimulation of gastrin secretion and of contributing to the hypergastrinaemia typical of @entity4801 . @entity24651 ES products were tested on an ovine antral mucosal preparation which had been developed for a pharmacological study of gastrin secretion in the @entity742 . Its responsiveness to chemical stimulation was established by stimulation with @entity1522 and @entity4478 : @entity2340 (0.1-5 mM) and @entity815 (10-100 mM) stimulated gastrin release (151-160 and 117-129%, respectively), whereas @entity2228 (0.1-100 mM) was without effect; @entity4859 , but not @entity2398 , stimulated gastrin release in concentrations from 1mM (122%) to 50mM (148%). ES products were prepared by incubation of exsheathed third-stage larvae (L3) or parasites recovered on Day 8 p.i. (L4), Day 12 p.i. (10% L4, 90% immature adults), Day 21 p.i. (5% L4, 30% immature adults, 65% adults), Day 22 p.i. (20% immature adults, 80% adults), Day 30 p.i. (adults) and Day 35 p.i. (adults), or a mixed-age parasite population. Worms were recovered from agar and incubated in either distilled water or Hank's balanced salt solution (HBSS) adjusted to pH 2.5, 3.5, 4.5, 5.0 or 7.4. HBSS pH 7.4 was also prepared with antibiotics, without @entity413 , and with antibiotics but without @entity413 . Survival of Day 21 and 35 worms and exsheathed L3 in water or in a series of HBSS adjusted to pH 2.5, 3.5, 4.5, 5.0 or 7.4 was assessed from the percentage of motile parasites. L3 slowly became immotile over several days except in HBSS pH 2.5, in which survival was reduced, whereas adult worms did not tolerate incubation at 37 degrees C in water or HBSS at pH 2.5, retained motility for about 2 days at pH 3.5, but survived well at pH 4.5 and above. Incubates prepared from all stages of @entity24651 , both in media favourable and unfavourable for parasite survival, failed to stimulate consistently the secretion of gastrin by tissue from both parasite-naive and previously exposed @entity742 , whereas a considerable number of incubates were significantly inhibitory. The inhibitor may not be produced by the @entity2199 , but by contaminating abomasal or environmental microflora, as inhibitory activity was predominantly generated by prolonged incubation, it was less potent when @entity413 was omitted and was not present in media containing antibiotics. This study did not find evidence for a gastrin stimulant in @entity24651 ES products, but did demonstrate the acid intolerance of adult worms and suggests that abomasal microbes may be capable of modulating the secretory activity of the host digestive tract.

Effect of XXXX excretory/secretory products on gastrin release in vitro.

@entity24651 :: ('45464', 'Species') :: ['O. circumcincta', 'Ostertagia circumcincta'] @entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity2199 :: ('6239', 'Species') :: ['nematodes'] @entity742 :: ('9940', 'Species') :: ['sheep'] @entity2228 :: ('CHEBI:57305', 'Chemical') :: ['glycine'] @entity4859 :: ('CHEBI:62946', 'Chemical') :: ['ammonium sulphate'] @entity4478 :: ('MESH:D000588', 'Chemical') :: ['amines'] @entity2340 :: ('CHEBI:27897', 'Chemical') :: ['tryptophan'] @entity2398 :: ('CHEBI:32149', 'Chemical') :: ['sodium sulphate'] @entity4801 :: ('MESH:D010272', 'Disease') :: ['abomasal parasitism'] @entity815 :: ('CHEBI:28044', 'Chemical') :: ['phenylalanine'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose']
@entity24651 :: (45464,Species) :: ['Ostertagia circumcincta']
