Preovulatory changes in glycosaminoglycans and collagen content in the stigma region of the follicle of the domestic hen.

The present study determined the amount and types of glycosaminoglycans and collagen concentrations in follicles of the domestic hen. The stigma (S; the area of follicular rupture) and nonstigma (NS) regions of the theca layer were isolated from the preovulatory follicle (F1) and an immature follicle (F2) that were to ovulate 30 min and 26 h later, respectively. Glycosaminoglycan density, which was estimated by measuring follicular uronic acid concentration (micrograms/mg dry wt), was lower (p less than 0.01) in F1S (2.6 +/- 0.1) compared to F1NS (3.4 +/- 0.2), F2S (3.4 +/- 0.1), and F2NS (3.4 +/- 0.1). Theca glycosaminoglycans consisted of approximately 58% dermatan sulfate, 20% heparan sulfate, and 22% hyaluronic acid. The F1S contained lower (p less than 0.05) amounts of dermatan sulfate and hyaluronic acid compared to F1NS, F2S, and F2NS. There was no significant difference in amounts of heparan sulfate in the F1S, F1NS, F2S, and F2NS. Collagen density, which was estimated by measuring follicular hydroxyproline concentrations (micrograms/mg dry wt), were lower (p less than 0.01) in F1S (20.3 +/- 1.4) and F2S (19.8 +/- 1.4) compared to F1NS (28.9 +/- 1.9) and F2NS (29.9 +/- 2.7). However, there was not a further decrease in collagen concentration in the F1S compared to F2S. We suggest that glycosaminoglycans may be degraded specifically in the stigma region of the preovulatory follicle prior to ovulation. The lower amount of collagen in the stigma region may decrease the tensile strength in the stigma compared to the nonstigma region regardless of maturational stage.