The effect of castration on the synthesis and secretion of proteins in 7,12-dimethylbenz(a)anthracene-induced rat mammary tumors.
The effect of castration on the incorporation of [35S]methionine into secreted proteins in 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumors, was investigated. Biopsy specimens were obtained from 19 tumors, 0, 24, 48, 72, and 96 h after castration. In 14 tumors, castration induced an increase in the incorporation (mean of 5-fold), reaching the maximal level after 24 h (3 tumors), 48 h (7 tumors), 72 h (3 tumors), and after 96 h (1 tumor). In three tumors castration did not alter the incorporation rate, while in two tumors incorporation declined immediately after castration. One-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the labeled secreted protein showed that castration did not decrease or increase significantly the incorporation of [35S]methionine into any of the major labeled proteins.


CONCLUSIONS
tumor regression following hormonal deprivation is apparently preceded by an increased synthesis of secreted proteins. However, no qualitative differences in any major labeled proteins could be observed.
Geier
A
A
Institute of Endocrinology, Chaim Sheba Medical Center, Tel Hashomer, Israel.
Hemi
R
R
Beery
R
R
Lunenfeld
B
B
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000737:chemistry; D010052:Ovariectomy; D051381:Rats; D013997:Time Factors
D009363:Neoplasm Proteins; D015127:9,10-Dimethyl-1,2-benzanthracene