Follicular fluid alpha 1-antitrypsin--correlation with fertilizing capacity of oocytes.

Follicular fluid and serum concentrations of alpha-antitrypsin (alpha 1-AT) were determined by radial immunodiffusion in 72 samples obtained from 33 infertile women undergoing in-vitro fertilization and embryo transfer. A statistically significantly lower concentration of alpha 1-AT was found in follicular fluids from which mature oocytes were recovered (mean 1.52, SE 0.06 g/l) than in those yielding immature oocytes (mean 2.96, SE 0.22 g/l). There was also a significantly higher rate of fertilization (85%) for oocytes from follicular fluids with alpha 1-AT concentrations of less than or equal to 2.0 g/l than for those obtained when the alpha 1-AT concentration was greater than 2.0 g/l (only 25%). The mean follicular fluid alpha 1-AT concentration (1.52, SE 0.06 g/l) of follicles yielding mature oocytes was significantly lower than the relevant mean serum concentration (3.17, SE 0.10 g/l). There was, however, no significant difference between follicular and serum concentration of alpha 1-AT in the group yielding immature oocytes or in the serum concentrations between the different oocyte maturity groups. The measurement of follicular alpha 1-AT may be a useful adjunct in predicting which oocytes are mature and likely to be fertilized.