21 carbon compounds to which non-phenolic ring and different groups are attached.
Source & Biosynthesis
Natural and synthetic
1. Progestrone derivatives
- Hydroxyprogestrone caproate
- Medroxyprogestrone acetate
2. 17-Ethinyl testosterone derivatives
3. 19-Nortestosterone derivatives
Routes of administration –oral, i/M, implants, transdermal, form of depo preparations
Hydroxylation & conjugation occurs in the body, excreted in urine
Mechanism of action
Two isoforms of progesterone receptors are present – A & B –these are intracellular receptors, mechanism is same as estrogen.
Physiological & Pharmacological Effects
Because of feedback on releasing hormones regulate release of different gonadotropins and gonadal hormones
Development of uterus and endometrial lining responsible for glandular growth. In secretory phase, responsible for start of menstrual bleeding.
- Increased basal levels
- Produced in response to carbohydrate diet.
- Lipid metabolism increase in lipoprotein lipase activity, increase in LDL and cholesterol. Effect is opposite to estrogens.
- Decreased amino acids in plasma leading to decreased nitrogen excretion.
- Depressant effect hypnotic –given bedtime
- Body temperature increased during mid cycle time increased if used as predictor of ovulation, exact mechanism is not known.
Effect on respiration
- Increased ventilator response to carbon dioxide
- Decreased blood carbon dioxide during luteal phase
- Maintains pregnancy, changes responsible for placenta formation
- Suppress uterine contractions
b. Decreased HDL increased atherosclerosis
c. Increased chances of breast cancer
- Hormone replacement therapy
- Abnormal / Dysfunctional Uterine Bleeding
- Dysmenorrhea / Endometriosis
- Diagnostic Uses
See whether estrogen, if on stoppage of progesterone withdrawal bleeding, if no estrogen no withdrawal bleeding
- Endometrial carcinoma –decreased chances when given with estrogen
- Luteal phase support –rise in temperature
- Premature labor
- Habitual abortions –controversial use
Acts on progestrone & glucocorticoid receptors
- Contraceptive 600 mg single dose post coital as emergency contraceptive
- Abortifacient – PGE1
In early pregnancy during 1st two months along with PGE1 pessaries used (4-6 mg given for 4 days or 800 mg for 2 days along with 1 mg PGE1 pessary as abortifacient
- Cushing’s syndrome
- Breast cancer