Effects of Prolactin on Fertilization and Cleavage of Human Oocytes

Abstract

The effects of PRL on fertilization and cleavage of human oocytes and subsequent pregnancy were studied. Forty-five patients (47 cycles) with euprolactinemic normal menstrual cycles undergoing in vitro fertilization (IVF) for the treatment of tubal infertility were selected for this study. The patients were divided into three groups dependent upon their mean serum PRL concentrations for the 3 days prior to Oocyte retrieval; hypoprolactinemic ( < 10 µg/I), euprolactinemic (10–30 µg/l) and hyperprolactinemic cycles (≧30 µg/I). Multiple follicular development was induced with hMG, and 10 patients were randomized to receive bromocriptine beginning with the previous menstrual cycle. In the hypoprolactinemic cycle group the fertilization rate was significantly lower than in the hyperprolactinemic cycle group, and the cleavage rate was significantly lower than in the other groups. The fertilization rates and the cleavage rates in the hyperprolactinemic cycle group were higher than those in the euprolactinemic cycle group; however, these differences were not statistically significant. While the pregnancy rates in the euprolactinemic cycle group were higher than in the other two groups, the numbers were too small for meaningful statistical comparison. The present study demonstrates that below normal concentrations of PRL have deleterious effects on IVF outcome. These data suggest that PRL may play a beneficial stimulatory role in Oocyte maturation and the acquisition of developmental capacity.

Does the bromocriptine-rebound method improve embryo quality?

“…In our study, morphologically better embryos can be transplanted using the BR method in woman with previous failed ART attempts. PRL is known to play a significant role in regulating ovarian functions, including folliculogenesis, steroid genesis, ovulation, and corpus lutenum function (3,4). PRL levels are generally high in patients with ovulation and steroidogenesis disorders.…”

Null mutation of the prolactin receptor gene produces multiple reproductive defects in the mouse.

“…A number of studies have examined the prolactin concentration of follicular fluid in maturing ova. Generally, a higher level of prolactin is seen in follicles containing mature oocytes capable of being fertilized (Laufer et al 1984;Bohnet et al 1985;Reinthaller et al 1987a,b;Gonen and Casper 1989;Seibel et al 1989;Oda et al 1991;Yoshimura et al 1991), although others find no relationship (Messinis and Templeton 1987) or suggest a negative effect (Irahara et al 1991). Using immature eggs collected from mouse ovaries, prolactin was found to increase the rate of germinal vesicle breakdown and subsequent fertilization and correct development in vitro (Randall et al 1990).…”

A Therapeutic Role of Prolactin Supplementation in Ovarian Stimulation forin VitroFertilization: The Bromocriptine-Rebound Method

“…These observations suggest that PRL plays a physiological role in human folliculogenesis. Hypoprolactinemia, induced with continuous administration of bromocriptine, is associated with lower rates of fertilization (10,11) and embryonic cleavage (11). Hypoprolactinemia, induced with continuous administration of bromocriptine, is associated with lower rates of fertilization (10,11) and embryonic cleavage (11).…”