RESUMEN
The effect of 90 minute supine restraint or forced swim stress, on weights of various organs in sixty adult male albino rats was studied. One group of twenty rats served as control; second group of twenty was immobilized and third group of twenty was forced to swim in water at room temperature. The animals were studied for a period of 15 days. During this period, they were subjected to 90 minutes of stress everyday at the same time. Both the groups of stressed animals showed a statistically significant increase in weight of cerebrum, cerebellum, pituitary, thyroid, and adrenals. Testes and seminal vesicles showed no significant change in weight. There was an apparent increase in weight of liver after immobilization stress, and a statistically significant increase in its weight in forced swim group. Therefore, immobilization and forced swim stresses produce an increase in the weight of brain cerebrum and cerebellum, endocrine organs and liver.