steroid hormone progesterone 2014-01-09T17:37:07Z Condition in which the main influencing factor is the steroid hormone progesterone, the principal pro-gestational hormone liberated by the corpus luteum, adrenal cortex, and placenta, whose function is to prepare the uterus for the reception and development of the fertilized oocyte by inducing transformation of the endometrium from the proliferative to the secretory stage. XCO:0000381 experimental_condition_ontology jsmith