| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Regular Article |
a Eutheria Foundation, Cross Plains, Wisconsin 53528 Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706
Deviation during a follicular wave in mares begins when the largest follicle (F1) reaches a mean diameter of 22.5 mm and is characterized by continued growth of F1 to become the dominant follicle and regression of F2 to become the largest subordinate follicle. In the present study, F1 was ablated at the expected beginning of deviation (Hour 0) to provide a reference point for characterizing the intrafollicular changes preceding experimental deviation between F2 and F3. Diameters and concentrations of follicular fluid factors in F2 and F3 were determined in F1-ablated mares at Hours 0, 12, 24, 48, or 72 (n = 8 mares/group). Circulating FSH concentrations were greater (P < 0.05) in the Hour 72 ablation group than in controls 12 h after ablation and then progressively decreased. The diameters of F2 and F3 increased (P < 0.05) during Hours 0 to 24. Thereafter, F2 continued to increase but F3 did not, indicating that experimental deviation began at Hour 24. The diameter of F2 and circulating FSH concentration at Hour 24 were similar (P > 0.1) to the diameter of F1 and FSH concentration at Hour 0, respectively. A differential change between F2 and F3 was not detected in follicular fluid concentrations of estradiol, inhibin-A, and activin-A by the beginning of experimental deviation. However, estradiol was higher in F2 at Hours 0 and 12 and inhibin-A was higher in F2 throughout the experiment, and both factors could have been involved in experimental deviation. Free insulin-like growth factor-1 (IGF-1) increased (P < 0.05) in F2 beginning at Hour 12 and was higher (P < 0.05) in F2 than in F3 by the beginning of experimental deviation. Temporally, this result indicated that intrafollicular IGF-1 was involved in conversion of F2 from a destined subordinate follicle to a dominant follicle.
1 Supported by the Eutheria Foundation, Cross Plains, WI, and the University of Wisconsin, Madison.
2 Correspondence: O.J. Ginther, Department of Animal Health and Biomedical Sciences, 1656 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706. FAX: 608 262 7420; ojg{at}ahabs.wisc.edu
3 C.M. is on leave from the Department of Animal Reproduction and Veterinary Radiology, School of Veterinary Medicine and Animal Science-UNESP, Botucatu, SP, Brazil
This article has been cited by other articles:
|
|
 |
|
  M A Beg and O J Ginther Follicle selection in cattle and horses: role of intrafollicular factors. Reproduction, September 1, 2006; 132(3): 365 - 377. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O J Ginther, E L Gastal, M O Gastal, and M A Beg In vivo effects of pregnancy-associated plasma protein-A, activin-A and vascular endothelial growth factor on other follicular-fluid factors during follicle deviation in mares Reproduction, April 1, 2005; 129(4): 489 - 496. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E D Watson, S-E Bae, R Thomassen, S R M Thomson, K Woad, and D G Armstrong Insulin-like growth factors-I and -II and insulin-like growth factor-binding protein-2 in dominant equine follicles during spring transition and the ovulatory season Reproduction, September 1, 2004; 128(3): 321 - 329. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T.J. Acosta, M.A. Beg, and O.J. Ginther Aberrant Blood Flow Area and Plasma Gonadotropin Concentrations During the Development of Dominant-Sized Transitional Anovulatory Follicles in Mares Biol Reprod, August 1, 2004; 71(2): 637 - 642. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O.J. Ginther, E.L. Gastal, M.O. Gastal, and M.A. Beg Critical Role of Insulin-Like Growth Factor System in Follicle Selection and Dominance in Mares Biol Reprod, May 1, 2004; 70(5): 1374 - 1379. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O.J. Ginther, E.L. Gastal, M.O. Gastal, C.M. Checura, and M.A. Beg Dose-Response Study of Intrafollicular Injection of Insulin-Like Growth Factor-I on Follicular Fluid Factors and Follicle Dominance in Mares Biol Reprod, April 1, 2004; 70(4): 1063 - 1069. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O.J. Ginther, D.R. Bergfelt, M.A. Beg, C. Meira, and K. Kot In Vivo Effects of an Intrafollicular Injection of Insulin-Like Growth Factor 1 on the Mechanism of Follicle Deviation in Heifers and Mares Biol Reprod, January 1, 2004; 70(1): 99 - 105. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
