Mortality and tumour incidence of Han:SPRD rats.

In a longevity study a total of 394 Han:SPRD rats (200 males and 194 females) were kept in a barrier type animal quarter from weaning until their natural death. The mean life span of males was 29.6 +/- 5 months, that of females 27.6 +/- 6.2 months. The most frequent neoplasms in females were mammary gland tumours (63.4%). Neoplasms of endocrine organs were common in animals of both sexes. Thyroid neoplasms, predominantly of C-cell origin, occurred in 60% of the males and 51.5% of the females. Pituitary gland tumours were observed in 53% of male and 45.1% of female rats. Further frequent tumours of the endocrine system included phaeochromocytomas (23% in males, 15.5% in females), adrenal cortex neoplasms (6% in males, 13.5% in females) and tumours of islet cells of the pancreas (20.8% in males, 8.2% in females). An uncommonly high incidence of squamous cell neoplasms (16% in males; 9.3% in females) of the preputial and clitoral gland was observed in this stock. Further organs frequently affected by neoplasms were the skin/subcutis and brain.