The gene expressions of macrophage colony-stimulating factor (MCSF) and MCSF receptor in the human myometrium during pregnancy: regulation by sex steroid hormones.

We investigated the biological effect of sex-steroid hormones, secreted from the corpus luteum and placenta, on the induction of mRNA encoding macrophage colony-stimulating factor (MCSF) and c-fms proto-oncogene (MCSF receptor) in the human uterine myometrium. Poly(A)+RNA was extracted from the myometrium of pregnant and non-pregnant uterine myometrium and then Northern blot analysis was performed on poly(A)+RNA. The myometrium of non-pregnant women expressed neither mRNA of macrophage colony-stimulating factor (MCSF) nor any transcript related to the c-fms proto-oncogene. On the other hand the myometrium of pregnant women expressed MCSF mRNA (4.7 kb) and two kinds of transcript related to the c-fms proto-oncogene (3.9 and 1.3 kb). The mRNAs of both MCSF and c-fms proto-oncogene were induced in the uterine myometrium of non-pregnant women under pseudopregnant therapy of mestranol and norethindrone. These results indicate that sex steroid hormone secreted from the corpus luteum of pregnancy and/or placenta may be deeply involved in the hypertrophic change of uterus during pregnancy by inducing MCSF and MCSF receptor (c-fms proto-oncogene protein product) in the myometrium.