Neonatal organophosphorus pesticide exposure alters the developmental trajectory of cell-signaling cascades controlling metabolism: differential effects of diazinon and parathion.
BACKGROUND
Organophosphorus pesticides (OPs) are developmental neurotoxicants but also produce lasting effects on metabolism.


OBJECTIVE
We administered diazinon (DZN) or parathion (PRT) to rats on postnatal days 14 at doses straddling the threshold for systemic signs of exposure and assessed the effects on hepatic and cardiac cell signaling mediated through the adenylyl cyclase (AC) cascade.


RESULTS
In the liver, DZN elicited global sensitization, characterized by parallel up-regulation of AC activity itself and of the responses to stimulants acting at beta-adrenergic receptors, glucagon receptors, or G-proteins. The effects intensified over the course from adolescence to adulthood. In contrast, PRT elicited up-regulation in adolescence that waned by adulthood. Superimposed on these general patterns were effects on glucagon receptor coupling to AC and on responses mediated through the Gi inhibitory protein. The effects on the liver were more substantial than those in the heart, which displayed only transient effects of DZN on AC function in adolescence and no significant effects of PRT. Furthermore, the hepatic effects were greater in magnitude than those in a brain region (cerebellum) that shares similar AC cascade elements.


CONCLUSIONS
These findings indicate that OPs alter the trajectory of hepatic cell signaling in a manner consistent with the observed emergence of prediabetes-like metabolic dysfunction. Notably, the various OPs differ in their net impact on peripheral AC signaling, making it unlikely that the effects on signaling reflect their shared property as cholinesterase inhibitors.
Adigun
Abayomi A
AA
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Wrench
Nicola
N
Seidler
Frederic J
FJ
Slotkin
Theodore A
TA
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002531:Cerebellum / Q000187:drug effects / Q000201:enzymology; D003976:Diazinon / Q000009:adverse effects*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006321:Heart / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D009943:Organophosphorus Compounds / Q000009:adverse effects*; D010278:Parathion / Q000009:adverse effects*; D010575:Pesticides / Q000009:adverse effects*; D011247:Pregnancy; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D009943:Organophosphorus Compounds; D010575:Pesticides; D010278:Parathion; D000262:Adenylyl Cyclases; D003976:Diazinon