HORMONAL PROTECTION OF RATS BREATHING OXYGEN AT HIGH PRESSURE1,2

Sex differences in susceptibility to high pressure oxygen (OHP)-induced convulsions were observed in mature rats. Male rats convulsed significantly earlier than did females. After adrenalectomy, seizures disappeared in most females and some male rats. The number of adrenalectomized male rats which resisted OHP-induced convulsions increased from 40 % to 91 % when they were treated with estradiol subcutaneously. Rats which do not convulse during the exposure to OHP eventually develop pulmonary edema and congestion and die. Strain variations in respect to susceptibility to oxygen poisoning and the contreversal nature of OHP and electroshock-induced convulsions in response to steroid hormones are discussed.