The acute oral toxicity of parathion in relation to dietary protein

Summary

The clinicopathological syndrome of acute oral toxicity to parathion (98.5% technical) was determined in male albino rats fed for 28 days from weaning on a diet containing 3.5% protein as casein (group I), normal amounts of protein as casein (26% group II), and normal amounts of mixed natural protein as laboratory chow. The LD₅₀±S.E. was found to be 4.86±0.31 mg/kg in group I, 37.1±4.9 mg /kg in group II and 23.4±5.4 mg/kg in group III. The LD₅₀ in group I was significantly lower than that in group II which, in turn, was significantly higher than that in group III. Most deaths occurred at 10–35 hours in all three groups. The clinical syndrome of intoxication was essentially the same in all three groups and included signs of cholinergic stimulation such as diarrhea, sialarrhea and dacryorrhea, of stimulation of the central nervous system such as piloerection, tremors, and exophthalmos, alternating with signs of depression of the central nervous system such as hyporeflexia, drowsiness, ataxia, prostration and pallor. These signs were accompanied by anorexia, oligodipsia, hypothermia, loss of body weight, oliguria, proteinuria, hematuria and glucosuria. At autopsy there were found a very mild local irritant gastroenteritis, vascular congestion of many organs, a contracted spleen and, when death was delayed, gastric ulcers and degenerative changes in organs such as the liver and kidneys. Most organs were dehydrated and had lost weight. The survivors appeared normal by the 4th day but there was a persistent hematuria, glucosuria and proteinuria. Organ weights and water contents were mostly within normal limits at 2 weeks and 1 month but autopsy at these intervals occasionally disclosed healed or healing abscesses, indicating that resistance to infection had been lowered by parathion, and other residual changes such as a megacolon and hydrated muscle.

Zusammenfassung

Die akute perorale Toxizität von Parathion (98,5% technisch) wurde an jungen, männlichen Albino-Ratten bestimmt. Die Tiere in Gruppe I erhielten eine gereinigte Diät, in der Eiweiß als Casein in sehr geringen Mengen (3,5%) enthalten war, in Gruppe II die gleiche Nahrung wie Gruppe I, jedoch mit Casein in normaler Menge (26%), und in Gruppe III die übliche gepreßte Trockennahrung (Chow). Die LD₅₀±S.F. betrug in Gruppe I 4,86±0,31 mg/kg Körpergewicht, 37,1±4,9 mg/kg in Gruppe II, und 23,4±5,4 mg/kg in Gruppe III. Das klinisch-pathologische Vergiftungssyndrom war im wesentlichen in allen 3 Gruppen gleich. Die klinischen Manifestationen umfaßten: Haaraufrichtung, Diarrhöe, Sialarrhoe, Dakryorrhoe, Hemodakryorrhoe, Nasenbluten, Exophthalmus, Zittern, Hyporeflexie, Lustlosigkeit, Ataxie, Anorexie, Oligodipsie, Körpergewichtsverlust, Oligurie, Albuminurie, Hematurie, und Glykosurie. Die meisten Todesfälle traten nach 10–35 Std ein. Bei der Autopsie fanden sich geringe akute Enteritis, ausgedehnte Erweiterung der venösen Capillaren, degenerative Veränderungen in Leber und Nieren und Wasserverlust und Gewichtsverlust der Körperorgane. Die Überlebenden schienen nach 4 Tagen wieder normal zu sein, die Organgewichte sowie der Wassergehalt lagen nach 2 Wochen und nach 1 Monat in den Normbereichen.