Chondroitin sulfate: an indicator of atresia in bovine follicles.

Estrogen (E), progesterone (P), and chondroitin sulfate (CS) concentrations in follicular fluid from 172 small (5-mm), 213 medium (6- to 10-mm), and 91 large (11- to 20-mm) individual bovine follicles were measured. Follicular health was classified by three methods; 1) histological examination for mitotic and pyknotic granulosa cell nuclei, 2) follicular E concentrations, and 3) the ratio of E to P (E/P). All three methods were significantly correlated. The highest correlation existed between follicular E concentrations and E to P ratio. Atretic follicles contained significantly less E and greater concentrations of P and CS than healthy follicles. CS concentrations significantly decreased as follicle size increased. E and P values did not change in relation to follicle size regardless of follicle health. Concentrations of E were significantly negatively correlated to P and CS, but P and CS were significantly positively correlated among all follicles. Thus, healthy follicles had elevated concentrations of E with relatively low P and CS, whereas atretic follicles had low amounts of E with elevated P and CS.