🔴 Mechanism of Action 🔴

🔺 Progestins :- PR (progesterone receptor) has limited distribution in the body,
mostly to the female genital tract, CNS, pituitary.
PR normally present in the nucleus of target cells. ( Details in general pharmacology)

🔺 Actions

1.Uterus :- secretory changes in the estrogen primed endometrium.

2. Cervix :- watery cervical secretion.

3. Vagina:- Induce pregnancy related changes in the vaginal mucosa.

4. Breast :- Proliferation of acini in mammary cells.

5.CNS :- High circulating concentration of progesterone appears sedative effect. Also affect mood.

6.Body temperature :- Slightly rise 5 degree Celsius.

7. Respiration :- stimulate respiration at high dose.

8. Metabolism :- raise LDL and Lower HDL cholesterol level.

9. Pituitary :- weak inhibition of Gn secretion from pituitary.

Dear Friends please note that , those MCQ having no subject mentioned on are the MCQs from the previous year Question paper .

🔴 Mechanism of Action 🔴

🔺 Antiprogestin :-

A. Mifepristone :-
It is a partial agonist and competitive antagonist at both A and B forms of PR. It is now retarded as Progesterone receptor modulator rather than pure antagonist.
Mifepristone sensitizes the myometrium to PGs (Prostaglandins)and induces menstruation. If implantation has occured , it blocks decidualization, so that the conceptus is dislodged, HCG production falls, secondary luteolysis occurs..... Endogenous progesterone secretion decreases and cervix is softened... All these effects leads to abortion.

B. Ulipristal:- It is recently aproved selective progesterone receptor modulator (SSRM) for use as emergency contraceptive. It inhibit ovulation by suppressing LH surge as well as by direct effect on follicular rupture.
In addition, it's action on endometrium can interfere with implantation.

C. Onapristone :- a pure progesterone antagonist.

D. Gestinone :- other antiprogestin more effective in endometriosis.

🔴ADR OF ANTIPROGESTIN🔴
Headache
Nausea
Vomiting
Abdominal pain
Menstrual delay
ovarian cyst