Cellular origin and induction of pregnancy-associated alpha 2-glycoprotein synthesis in pregnant rats

The synthesis of alpha 2-PAG was measured and compared in tissues and cells from normal non-pregnant females, and maternal and fetal rats in vitro to define the target cells hormonally regulated during pregnancy. Synthesis was measured by L-14C]leucine incorporation into immunochemically isolated alpha 2-PAG and confirmed by radioimmunodiffusion. alpha 2-PAG synthesis was demonstrated in maternal peripheral blood leucocytes, placenta, breast, spleen, liver and fetal peripheral blood leucocytes and liver. Maternal and fetal liver were the most active tissue producers and fetal liver synthesized 4 times more alpha 2-PAG than did maternal liver. Furthermore, fetal peripheral blood leucocytes synthesized 2 times more alpha 2-PAG per cell than did these same maternal cells. A direct comparison of synthesis by cells from pregnant and non-pregnant female rats revealed that (1) maternal peripheral blood leucocytes synthesized 5 times more alpha 2-PAG per cell than did normal leucocytes, although these same cells synthesized approximately equal amounts of total cell protein per cell, (2) maternal peritoneal exudate macrophages also synthesized 5 times more alpha 2-PAG per cell than did macrophages obtained from normal female rats, and total protein synthesis by these cells also closely paralleled each other, (3) maternal and fetal plastic-adherent peripheral blood monocytes synthesized 22 and 58 times more alpha 2-PAG per cell respectively than did normal monocytes, (4) maternal and fetal non-adherent lymphocytes synthesized 8 and 16 times more alpha 2-PAG per cell respectively than did normal lymphocytes and (5) fetal monocytes and lymphocytes synthesized 3 and 2 times more alpha 2-PAG per cell than did maternal monocytes and lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)