Abstract
A cyclic variation in plasma levels of pregnancyassociated murine protein-1 (PAMP-1) during the oestrus cycle in outbred Pan : Thei mice was recorded. PAMP-1 plasma levels were significantly elevated in dioestrus as compared with the three other stages of the murine oestrus cycle. Until day 7 of gestation the PAMP-1 plasma levels remained low, and no significant differences could be observed between pregnant and pseudopregnant female mice. The PAMP-1 levels increased markedly in the circulation on day 8 of pregnancy, and continued to increase until peak values were reached at day 11 of pregnancy. In the latter half of pregnancy the PAMP-1 levels declined until day 17 of pregnancy, at which stage the normal non-pregnant values were recorded.