Changes in linoleic acid during follicular development and inhibition of spontaneous breakdown of germinal vesicles in cumulus-free bovine oocytes.

The fatty-acid composition of follicular fluid from small and large developing follicles was analysed and the effects of saturated and unsaturated fatty acids on spontaneous breakdown of germinal vesicles were investigated. Fatty acids were bound to bovine serum albumin and cultured with oocytes at 100 mumol/l. Linoleic acid (18:2) was the only fatty acid tested that significantly inhibited breakdown of germinal vesicles (P less than 0.01). The effect was dose-dependent and was greatest at 50 mumol fatty acid/l (% breakdown of control, 81.1 +/- 6.8 vs. 50 mumol linoleic acid/l, 35.4 +/- 7.3; P less than 0.02). Linoleic acid was the major fatty acid, constituting about a third of the total fatty acid in the follicular fluid; followed by 18.9 +/- 1.0% and 16.9 +/- 1.3% oleic acid (18:1) in small and large follicles, respectively. Saturated fatty acids accounted for less than 30% of the total fatty acid composition. There was a marked absence of tetraenoic acids in small and large follicles. Proportions of linoleic acid were significantly lower in follicular fluid from large follicles (31.1 +/- 1.2% of total fatty acid) than from small follicles (34.8 +/- 0.7% of total fatty acid) (P less than 0.05) and there was a significant inverse correlation between follicle diameter and percentage of linoleic acid in the follicular fluid (r = -0.6966; P less than 0.05). There was no significant alteration in any other fatty acid during follicular development.(ABSTRACT TRUNCATED AT 250 WORDS)