Hyperprolactinemia and hyperadrenocorticism accompanied by normal blood pressure in Sprague-Dawley rats

Pituitary glands removed from adult female normotensive Sprague-Dawley (S-D) rats were implanted beneath the renal capsule of 100-day male S-D rats. Female neonatal S-D rats were given a single sc injection of 1.25 mg of testosterone proprionate (TP) suspended in sesame oil. Systolic blood pressure and blood samples were taken at various time intervals postimplantation and TP treatment prio to autopsy. Both the TP treatment and pituitary implants caused hyperprolactinemia, increased adrenal weight concomitant with thymus gland involution, hypersecretion of corticosterone, but no increase in systolic blood pressure. It is suggested that the failure of these hyperprolactinemic S-D rats to develop hypertension was due to the absence of a genetically mediated hypertensinogenic factor present in this normotensive strain which is activated by chronic hyperprolactinemia.