Effect of repeated administration of soman on selected endocrine parameters and blood glucose in rats.

The effects of repeated administration of soman on plasma glucose levels, acetylcholinesterase (AChE) activity in erythrocytes and hypothalamus, and plasma levels of corticosterone, glucagon, insulin, epinephrine, and norepinephrine were studied in male rats. Rats were given soman subcutaneously (sc), either 30 micrograms/kg every 24 hr for 5 or 12 days or 40 micrograms/kg every 24 hr for 5 days. All doses of soman markedly depressed AChE activity in the hypothalamus and completely inhibited AChE activity in erythrocytes. Soman 30 micrograms/kg given for 5 days did not alter plasma levels of any hormone assayed and produced few signs of intoxication. Soman 40 micrograms/kg given for 5 days elevated plasma levels of glucose and corticosterone and produced signs of severe cumulative intoxication. Daily administration of 30 micrograms/kg of soman for 12 days inhibited hypothalamic AChE activity 75%, lowered plasma insulin, and produced signs of moderate intoxication. Repeated administration of soman produced endocrine alterations only when significant signs of intoxication were evident. The absence of increases in plasma levels of catecholamines and corticosterone in rats exhibiting signs of moderate intoxication, and of catecholamines in rats exhibiting signs of severe intoxication, may indicate an impairment by soman of the normal endocrine response to stress.