since a ) a preparation containing isoforms 1 , 2 , and 3 was found to induce autoregulation in gh3 cells , b ) isoform 1 is not a secreted form , and c ) isoform 2 does not cause autoregulation ( at least in gh3 cells ) , it is deduced that isoform 3 is an autocrine form of prl .
C1327616
secreted
C0007634
cells