| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom and
and
Division of Integrative Biology, Roslin Institute, Roslin, Midlothian EH25 9PS, United Kingdom
3 Correspondence: Sutton Bonington Campus, Loughborough, Leicestershire (phone: 0115 951 6061; fax: 0115 951 6069; e-mail: bob.webb{at}nottingham.ac.uk).
Regulation of ovarian activity is an integrated process encompassing both extraovarian signals and intrafollicular factors. Initiation of primordial follicle growth and the early stages of folliculogenesis can occur without gonadotropins, but FSH may affect the rate of preantral follicle growth. Antral follicle development from 1 to 4 mm in sheep and cattle is completely gonadotropin dependent. These recruited follicles express a range of mRNA encoding steroidogenic enzymes, gonadotropin receptors, and local regulatory factors and their receptors. As follicles continue to mature, there is a transfer of dependency from FSH to LH, which may be part of the mechanism involved in selection of follicles for continued growth. Locally produced growth factors, such as the IGF and members of the transforming growth factor-ß superfamily, work in concert with gonadotropins throughout the follicular growth continuum and can have significant effects on follicle selection. Environmental influences, such as changes in nutrition, also have an effect on ovarian activity. This can occur without significant variation in circulating gonadotropin concentrations and can be correlated with changes in circulating concentrations of metabolic hormones, including insulin, IGF-I, GH, and leptin. Nutrition can also affect the expression of mRNA encoding components of the ovarian IGF system to regulate the sensitivity/response of follicles toward gonadotropins. Hence, the roles of growth factors in follicular development and survival depend on gonadotropin status and differentiation state of the follicle. In conclusion, it is the integration of these extraovarian signals and intrafollicular factors that determine whether a follicle will continue to develop or be diverted into atretic pathways.
Key Words: Bovine • Follicle • Gonadotropins • Growth Factors • Nutrition
This article has been cited by other articles:
|
|
 |
|
  M. L. Rhoads, J. P. Meyer, S. J. Kolath, W. R. Lamberson, and M. C. Lucy Growth Hormone Receptor, Insulin-Like Growth Factor (IGF)-1, and IGF-Binding Protein-2 Expression in the Reproductive Tissues of Early Postpartum Dairy Cows J Dairy Sci, May 1, 2008; 91(5): 1802 - 1813. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Forde, M. Mihm, M. J. Canty, A. E. Zielak, P. J. Baker, S. Park, P. Lonergan, G. W. Smith, P. M. Coussens, J. J. Ireland, et al. Differential expression of signal transduction factors in ovarian follicle development: a functional role for betaglycan and FIBP in granulosa cells in cattle Physiol Genomics, April 21, 2008; 33(2): 193 - 204. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Zachow and M. Uzumcu The hepatocyte growth factor system as a regulator of female and male gonadal function J. Endocrinol., December 1, 2007; 195(3): 359 - 371. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. F. Cooke, J. D. Arthington, C. R. Staples, W. W. Thatcher, and G. C. Lamb Effects of supplement type on performance, reproductive, and physiological responses of Brahman-crossbred females J Anim Sci, October 1, 2007; 85(10): 2564 - 2574. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. M. Chagas, J. J. Bass, D. Blache, C. R. Burke, J. K. Kay, D. R. Lindsay, M. C. Lucy, G. B. Martin, S. Meier, F. M. Rhodes, et al. Invited Review: New Perspectives on the Roles of Nutrition and Metabolic Priorities in the Subfertility of High-Producing Dairy Cows J Dairy Sci, September 1, 2007; 90(9): 4022 - 4032. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Blumenfeld How to Preserve Fertility in Young Women Exposed to Chemotherapy? The Role of GnRH Agonist Cotreatment in Addition to Cryopreservation of Embrya, Oocytes, or Ovaries Oncologist, September 1, 2007; 12(9): 1044 - 1054. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. Lucy The bovine dominant ovarian follicle J Anim Sci, March 1, 2007; 85(13_suppl): E89 - E99. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W Kim, R. P Rhoads, N. Segoale, N. B Kristensen, D. E Bauman, and Y. R Boisclair Isolation of the cDNA encoding the acid labile subunit (ALS) of the 150 kDa IGF-binding protein complex in cattle and ALS regulation during the transition from pregnancy to lactation. J. Endocrinol., June 1, 2006; 189(3): 583 - 593. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Borowczyk, J. S. Caton, D. A. Redmer, J. J. Bilski, R. M. Weigl, K. A. Vonnahme, P. P. Borowicz, J. D. Kirsch, K. C. Kraft, L. P. Reynolds, et al. Effects of plane of nutrition on in vitro fertilization and early embryonic development in sheep J Anim Sci, June 1, 2006; 84(6): 1593 - 1599. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S.J. Adamiak, K. Mackie, R.G. Watt, R. Webb, and K.D. Sinclair Impact of Nutrition on Oocyte Quality: Cumulative Effects of Body Composition and Diet Leading to Hyperinsulinemia in Cattle Biol Reprod, November 1, 2005; 73(5): 918 - 926. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Hess, S. L. Lake, E. J. Scholljegerdes, T. R. Weston, V. Nayigihugu, J. D. C. Molle, and G. E. Moss Nutritional controls of beef cow reproduction J Anim Sci, June 1, 2005; 83(13_suppl): E90 - 106. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
