Relationships between bovine follicular fluid glycosaminoglycans and steroids

The glycosaminoglycans chondroitin sulfate (CS) and heparan sulfate (HS) are present in follicular fluid. The present study evaluated estradiol (E), progesterone (P), CS, and HS concentrations from pools of 2633 small (less than 6 mm), 1702 medium (6-10 mm), and 491 large (greater than 10 mm) bovine follicles subdivided by relative E concentrations. E and P concentrations increased with follicle enlargement (P less than 0.05), but were inversely related within a follicle size. CS levels were reduced (P less than 0.05) in large (0.84 mg/ml) compared to small (1.18 mg/ml) and medium (1.36 mg/ml) follicles, while HS levels were decreased (P less than 0.05) in medium (0.34 mg/ml) and large (0.19 mg/ml) compared to small (1.10 mg/ml) follicles. Within a follicle size, CS and HS levels decreased significantly with increasing E. CS to HS ratios increased with follicle size and E concentration. The ratio of CS to HS was 4.4- and 1.6-fold higher, respectively, in medium and large follicular fluid samples classified healthy compared to atretic by their E content. These results support the idea that concentrations of glycosaminoglycans decrease with follicular maturation, and atretic follicles contain elevated levels of CS and HS.