Relationship of human oocyte maturity, fertilization, and cleavage to follicular fluid prolactin and steroids.

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Follicular fluid (FF) levels of prolactin (PRL), estradiol (E2), progesterone (P), and androstenedione (delta 4A) were related to diversities in oocyte maturation, fertilization, and cleavage among oocytes obtained for in vitro fertilization. Follicles with mature stage I oocytes contained similar concentrations of PRL and E2, more P, and less delta 4A compared to follicles containing immature oocytes. Follicles with mature stage II oocytes had higher amounts of P and E2 but similar levels of PRL and delta 4A compared to follicles with mature stage I oocytes. Prolactin was lower and E2 higher in FF associated with fertilizable oocytes than in those with unfertilized gametes. Follicles which yielded gametes that ultimately divided to more than four cells had the highest E2 levels, while the lowest E2 concentrations were associated with fertilized, uncleaved eggs. P, delta 4A, and PRL levels in FF were not related to oocyte cleavage. We conclude that human menopausal gonadotropin (hMG) treatment does not necessarily lead to a synchrony or uniformity of preovulatory follicles, maturation of oocytes is associated with rising levels of progesterone and decreasing levels of delta 4A in FF, an increased cleavage rate in vitro is associated with higher FF levels of E2, and high levels of PRL in FF are associated with unfertilized oocytes. These findings emphasize that differences in the hormonal milieu surrounding oocytes may have profound effects on the success of in vitro fertilization.