Cancer In Sprague-Dawley Rats Research Articles

Relation between growth of carcinogen-induced mammary cancers and serum prolactin values in rats.

SummaryMammary cancers were induced in fifty 50-55 day old female Sprague-Dawley rats by a single intravenous injection of 5 mg 7,12 -dimethylbenz (a) anthracene (DM BA). Total mammary cancers and average cancer diameter per rat were measured once weekly. Beginning about 45 days after the appearance of mammary cancers and approximately at monthly intervals thereafter, for a total of 165 days, serum prolactin was measured by radioimmunoassay. Although the average number of mammary cancers increased from an initial 1.5 ± 0.5 to a maximum of 7.4 ± 0.9 per rat, and average tumor diameter increased from 0.7 ± 0.1 to 1.4 ± 0.2 cm, serum prolactin concentrations remained within the normal range and did not change significantly from month to month. These observations indicate that growth of DMBA-induced mammary cancers in Sprague-Dawley rats can proceed in the presence of normal blood prolactin values.