Follicular fluid nitric oxide and ascorbic acid concentrations in relation to follicle size, functional status and stage of estrous cycle in buffalo

The objective of this study was to evaluate the changes in follicular fluid nitric oxide (NO) and ascorbic acid (AA) concentrations with varying follicle size and functional status, and stage of estrous cycle in buffalo. The main effect of follicle size on NO concentration and size-by-status interaction were statistically significant (P < 0.05). Small follicles had a higher (P < 0.05) NO concentration compared to medium and large follicles. Further, estrogen-active (EA) small follicles showed increased (P < 0.05) NO concentrations than the corresponding estrogen-inactive (El) follicles. Within EA category, higher (P < 0.01) concentrations were recorded in small compared to medium and large follicles. There was no significant main effect of stage (P > 0.1) on NO concentration but the stage-by-size interaction was significant (P < 0.05) with medium follicles showing a higher (P < 0.05) concentration during late luteal stage compared to the mid luteal stage. During early and mid luteal stages, higher (P < 0.05) NO concentrations were recorded in small than in medium follicles. A significant (P < 0.01) main effect of size on AA concentration was observed with higher values in medium than in small and large follicles. Size-by-status interaction for AA approached statistical significance (P < 0.06) with higher (P < 0.05) concentrations recorded in medium than in large EA follicles. The main effect of stage on AA concentration was, however, non-significant (P > 0.1) but the stage-by-size interaction approached statistical significance (P < 0.06) with lower (P < 0.05) levels recorded in large compared to medium size follicles during the follicular stage. In conclusion, the present study demonstrates that the concentrations of follicular fluid NO and AA vary according to the follicle size, functional status and stage of estrous cycle suggesting their possible role in process of follicular development during estrous cycle in buffalo. (C) 2011 Elsevier B.V. All rights reserved.