Kile E. Isom

Sex Differences and Incidence of Activity-Stress Ulcers in the Rat

Female rats housed in running-wheel activity cages and fed 1 hr. daily ran significantly more than similarly housed and fed male rats. Male rats survived an average of 10 days, whereas mean survival time for female rats was 7.3 days. Experimental activity rats developed glandular stomach ulcers. Pair fed controls housed in cages without activity wheels were ulcer-free. Among experimental activity rats, there were no sex differences with respect to the number or severity of ulcers.

A clinical evaluation of rats dying in the activity-stress ulcer paradigm

Abstract Rats fed 1 hr daily and housed in running-wheel activity cages exhibited excessive running and developed stomach ulcers as compared to food control, body weight control and home cage control rats. In addition to the observed gastric disease, experimental animals had increased bilirubins, decreased glycogen and decreased serum proteins suggesting that hepatic disease played a role in the lethal consequence of exposing rats to the activity-stress procedure. The decreases in liver glycogen and serum glucose suggested that the terminal problem was related to incipient exhaustion of metabolic substrates.

Age differences and stress ulcer in the rat

Rats 2-, 7- and 12-mo. old were exposed to supine body restraint plus cold (5 degrees C) for 3 hr. The mean cumulative length of lesions for the 2-, 7-, and 12 mo. old rats was 22.0, 43.0 and 16.0 mm. respectively. The same experimental design was used in a second study, but the pylorus was ligated prior to restraint. Total acid output/hr. was 134.6, 178.2, and 64.7 muEq/60 min. respectively for the three age groups. Older rats were not more susceptible to stress-ulcer and gastric acid was not significantly related to degree of ulceration.

Restricted feeding and incidence of activity-stress ulcers in the rat

Rats housed in running-wheel activity cages and fed 1 h daily exhibited excessive running and subsequently died revealing large stomach ulcers. However, prior experience with a 1-h feeding schedule for 15 days before exposure to the activity-stress procedure did significantly extend survival time. A second study illustrated that feeding schedules of.5, 1.0, 1.5, or 2.0 h daily did not yield differences in terms of stomach ulcers or survival time, but a 3-h daily feeding did significantly reduce ulcer incidence and increase survival time.

Cholesterol synthesis and metabolism as a function of unpredictable shock stimulation

Abstract Rats fed a high lipid diet and also exposed to unavoidable and unpredictable grid shock for 2 and 8 days showed higher levels of accumulated chemical cholesterol in aorta, kidney, liver and serum as compared to control rats fed only the high lipid diet. Thirty days of shock stress produced similar results except that kidney tissue revealed lower and nonsignificant levels of accumulated cholesterol. A differential cholesterol clearing mechanism for the various tissues is postulated to explain the relative vulnerability of aorta, liver and kidney to stress-induced cholesterol deposition.

The effects of environmental stress on cholesterol synthesis and metabolism

Abstract 1. 1. A study was done on the effect of stress on cholesterol deposition in various organs of pair-fed rats. 2. 2. There was an increased amount of cholesterol with aortas, livers, and serum of the stressed animals as compared to the control. 3. 3. There was only a transient elevation in the kidneys of the stressed animals. 4. 4. Evidence is presented that the kidney possesses a better mechanism for clearing cholesterol than the aorta.

Activity-stress gastric lesions in the chipmunk (Tamias striatus)

Chipmunks were allowed access to a running wheel and fed 1½ h each day. After 13 days of restricted feeding, all activity animals had died and postmortem pathology revealed extensive lesions of the glandular stomach. Food-yoked control animals, not allowed to exercise, very rarely died and showed minimal signs of stomach pathology when autopsied. Circadian running patterns of activity animals indicated a marked increase in diurnal running during restricted feeding. Results indicate that the activity-stress procedure is capable of producing stomach ulcers in a wild animal species.

Effect of glucagon and stress on cholesterol metabolism and deposition in tissues.

Abstract 1. 1. The effects of glucagon alone and glucagon plus stress on lipid levels in various organs were studied. 2. 2. Stress added to glucagon produced no significant change in cholesterol levels of the kidney, liver, and aorta. There were also no significant changes in the triglyceride levels of liver, aorta and serum. 3. 3. Stress did raise the level of diaphragm and serum cholesterol. 4. 4. Stress lowered kidney and diaphragmatic triglyceride in glucagon treated animals. 5. 5. The significance of these results are discussed.

Recording the electrocardiogram from the squirrel monkey, Saimira sciureus ☆

Abstract A technique is described for recording the EKG from the squirrel monkey by utilizing surface electrodes placed on the animals chest. The design of a commercially available restraining chair was modified to allow the monkey to operate a manipulandum and prevent the animal from disturbing the recording electrodes.

The effect of ethanol and high cholesterol diet on tissue lipids

Abstract The effect of moderate amounts of alcohol in rats on a high lipid diet were studied. It was found that alcohol tended to lower the cholesterol in the serum, kidney and liver and raise the triglyceride in the serum and aorta.