FOLLICLE-STIMULATING HORMONE-ENHANCED FIBRONECTIN PRODUCTION BY CHICKEN GRANULOSA-CELLS IS INFLUENCED BY FOLLICULAR DEVELOPMENT

Experiments were conducted in vitro to examine the effect of ovine follicle-stimulating hormone (FSH) on various fractions of fibronectin (deposited, secreted in medium, and cell-associated) resulting from culture (12 or 24 h) of chicken granulosa cells isolated from the largest (Fl) and third largest (F3) preovulatory follicles as well as from a pool of immature small yellow follicles (SYF). Fibronectin in each fraction was quantified with a specific ELISA. The amount of fibronectin deposited in culture wells containing unstimulated cells increased with time and was greatest in wells containing F1 cells. Follicle-stimulating hormone increased the quantity of fibronectin deposited within 12 h by F3 and SYF cells, but not by Fl cells. The magnitude of FSH-enhanced fibronectin deposition was greatest in cells derived from immature SYF. Fibronectin secreted in the medium by unstimulated cells also increased with the stage of follicular maturation. Follicle-stimulating hormone increased the amount of fibronectin secreted in the medium by F3 and SYF cells. The quantity of fibronectin associated with cells was increased by FSH in all cell types. Total (deposited plus medium plus cell-associated) fibronectin production was elevated in a dose- and time-dependent manner when FSH was added to F3 and SYF granulosa cells, but the gonadotropin was without effect in Fl cells. The magnitude of FSH stimulation (fold increase) of total fibronectin production was calculated as a multiple of the unstimulated (control) value for each cell type. The relative change in total fibronectin production resulting from addition of FSH (after 24 h incubation) was .02- to .24-fold in Fl cells as compared with .33- to .92-fold in F3 cells and 2.75- to 4.38-fold in SYF cells. These results indicate that FSH stimulates fibronectin production by chicken granulosa cells, and this stimulatory effect decreases as the follicle matures.