National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2009

12. Peripheral concentrations of reproductive hormones associated with follicular development throughout the estrous cycle of the sow

Japanese

  We investigated the changes in the peripheral concentrations of inhibin A, steroids, and gonadotropins throughout the intact estrous cycle of the sow in relation to ovarian changes determined by daily transrectal ultrasonography. Follicular recruitment was identified in 2 periods of the cycle: (1) from the late luteal to the follicular phase, characterized by an increase in the number of small follicles followed by the appearance of large follicles, and (2) during the early luteal phase, characterized by an increased number of small follicles. The plasma concentrations of inhibin A increased, coinciding with the 2 periods of follicle emergence. Estradiol levels increased during the follicular phase but not during the early luteal phase. An inverse relationship between the concentration patterns of inhibin A and follicle-stimulating hormone (FSH) was noted in the 2 periods of follicle emergence. In conclusion, the measurement of plasma inhibin A levels combined with ultrasonographic examination of the ovaries revealed 2 periods of synchronous follicular growth during the sow's estrous cycle.
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Reference:

Noguchi, M. et al. (2010) Reproduction. 139:153-161.

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