Mesulergine Induced Leydig Cell Tumours, a Syndrome Involving the Pituitary-Testicular Axis of the Rat

The scientific literature abounds with reports of spontaneous and induced Leydig cell tumours in rats. The spontaneous lesions are age related and range from an incidence of 5% in Sprague-Dawley rats (Prejean 1973) to an incidence approaching 100% in Fischer 344 rats (Turek 1979). The older literature reports that disturbed hormone relationships and testicular damage were all important in the induction of Leydig cell tumours. Injections of cadmium salts and partial vascular ligation were frequently used to induce such tumours (Gunn 1965). Gunn in 1963 reported that levels of luteinising hormone were raised in rats treated three months previously with cadmium and Roe in 1965, speculated on the inter-relationships between the pituitary, the testes, the hormones which these two organs secrete and Leydig cell tumours.