Question

Explain hormones maturation-inducing hormone (MIH) and HP

Answer 1

Solution:

MIH ( maturation-inducing hormone) is involved in the maturation phase of oocyte and HP (hydroxyprogesterone) is a precursor form of the enzyme MIH.

Activation of MIH:

Oocytes undergo growth and maturation phase, the former of which is triggered by FSH (follicle stimulating hormone) whereas the latter is induced by the hormone LH (leutinizing hormone).

LH acts on oocytes and leads to a chain of events, ultimately resulting in the formation of hydroxyprogesterone (HP).

HP is converted into dihydroxyprogesterone (DHP) by the action of another enzyme called hydroxysteroid dehydrogenase. DHP is called the maturation-inducing hormone (MIH) .

Function of MIH:

MIH acts to activate the maturation promoting factor (MPF) present in cytoplasm of oocytes.

MIH leads to synthesis of cyclin B, which then binds to cdc2 (cell division control protein) ​​​​​. The cyclinB-cdc2 complex is called the MPF (maturation promoting factor). MPF stimulates processes which finally lead to maturation of oocyte.

In short, HP is the precursor of MIH hormone , which is involved in the activation of MPF .