Role of the adrenal medulla in stress-induced hyperinsulinaemia in normal mice and in mice infected with Bordetella pertussis or treated with pertussis toxin.

Abstract

Intranasal infection of mice with a sublethal dose of Bordetella pertussis or the intravenous administration of purified pertussis toxin resulted in a marked increase in the serum immunoreactive insulin concentration following ether stress. This stress-induced hyperinsulinaemia was not modified significantly by blockade of alpha 2-adrenoceptors with idazoxan, beta-adrenoceptors with propranolol, autonomic ganglia with hexamethonium, opioid receptors with naloxone, muscarinic cholinoceptors with atropine or by adrenal demedullation. The effect of pertussis in promoting stress-induced hyperinsulinaemia was mimicked qualitatively by alpha 2-adrenoceptor blockade, adrenal demedullation or ganglionic blockade. However, the serum immunoreactive insulin response to ether stress was smaller in animals subjected to these procedures compared with the response seen in mice infected with B. pertussis or treated with pertussis toxin. Thus, in the mouse, acute stress produces hyperinsulinaemia under conditions in which the release of adrenal medullary catecholamines is prevented, or the inhibitory action on insulin secretion is blocked by alpha 2-adrenoceptor antagonists or by pertussis toxin.