Physiological Changes in Pregnancy
In ovulatory phase which of following is true (AIIMS May 2011)
|A||Stimulation of reduction division of oocytes|
|B||FSH increases steroid synthesis in granulosa cells|
|C||Activin cause FSH to act on granulosa cells|
|D||Inhibin A is increased|
Activin cause FSH to act on granulosa cells
1. The activins and inhibins are glycoproteins that belong to the transforming growth factor-ß superfamily. They are secreted from granulose cells.
2. FSH induces steroidogenesis (estradiol production) in granulosa cell in the preovulatory phase (follicular phase). Stimulation of the arrested meiotic division of the ovum occurs after fertilization.
3. Inhibin B has shown increased levels in mid-follicular phase, has a periovular peak, and then declines in luteal phase. Inhibin A is low in follicular phase, reaches a small peak in mid-follicular phase, and increases to reach a peak in luteal phase.
4. Activin has biphasic secretion with peak at the time of ovulation and nadir in mid-follicular and mid-luteal phases