Fatty acids are precursor of paracrine hormones involved in dominance,
ovulation and atresia mechanisms. Active and non-active follicles
of Friesian dairy cows were studied in order to investigate their fatty
acids profiles. Estrogen activity of follicles was defined as the ratio of
estrogens to progesterone concentrations in follicular fluid. Follicles
were assigned as active if their ratio was higher than one. Follicular
fluid lipids of 11 active and 11 non-active follicles were extracted using
the Bligh & Dyer method, methylated and separated using gas
chromatography. Concentrations were expressed as the percentage of
total lipids (mean ± SEM, n = 11). Active follicles showed lower
oleic (11.3% ± 0.63 vs 14.0% ± 0.93, p < 0.05), arachidonic
(3.0% ± 0.31 vs 4.2% ± 0.36, p < 0.05) and higher linoleic
(55.1% ± 1.05 vs 51.1% ± 1.02, p < 0.05) acid concentrations.
These variations in fatty acid concentrations are interesting in
understanding fatty acid metabolism during folliculogenesis. Decrease
in arachidonic acid concentrations might be due to increased
membrane incorporation as active follicles are not going in atresia
and as such need improved membrane synthesis to sustain follicular
growth. Arachidonic acid as a precursor of prostaglandin may also
play a role in the hormonal paracrine regulation of the ovulatory and
angiogenesis processes.
