For the synthesis of progesterone, the precursor is cholesterol. Two acetylâ€CoA molecules are interconverted and form squalene and lanosterol as intermediate products in the synthesis of progesterone. Now this cholesterol transported in plasma as LDL. This interacts with the receptors of vesicles and gets fuses with lysosomes. Hydrolases of lysosomes allow the intracellular release of free cholesterol, this free cholesterol converted into pregnenolone. There are two synthesis pathways are there Δ5â€hydroxy steroid pathway, Δ4â€ketosteroid pathway. At the time of follicular rupturing Graafian follicle release, the ovum and the granulosa cells which present in secondary follicles mature into the corpus luteum, this corpus luteum secret progesterone and estrogen during the luteal phase of the menstrual cycle. Corpus luteum enlarges 10-12 times if fertilization failed to happen in 1 to 2 days after ovulation, and release progesterone. In the case of fertilization, the corpus luteum grows more and produces huge progesterone for the first 2 to 3 months of pregnancy to facilitate implantation and maintain pregnancy. In the second and third trimesters placenta also helps in the synthesis of hormones to maintain pregnancy. Progesterone synthesis by corpus luteum is influenced by LH, FSH, PRL, β-adrenergic agents, and prostaglandins. Transcortin is a carrier of progesterone in blood. In the absence of pregnancy after ovulation or copulation, the corpus luteum reduces its product so progesterone level lowered in the body, which stimulates menstruation. Renal 21â€hydroxylation converts the progesterone which is circulating in the blood into deoxycorticosterone which is a corticosteroid.
Metabolic Effects of Progesterone
Progesterone increases the release of insulin followed by carbohydrate intake. Corticosteroids are used in medications for ‘carpal tunnel syndrome’ caused by diabetic neuropathy. Several studies revealed progesterone administration promotes myelin regeneration neuropathy patients. Progesterone as progestin along with estrogen used in contraceptive medicines and hormonal replacement therapy.
Action Over Central Nervous System
Progesterone takes part in a feedback mechanism to influence LH secretion by acts on hypothalamicâ€pituitary synthesis. allopregnanolone compound of progesterone shows neuroprotective and restorative effects during traumatic and ischemic brain injuries.
Progestin
Progestin will be administered to treat some reproductive illness like post menopause complication, amenorrhea, endometriosis, and irregular periods. This progestin is marketed in many forms capsules, vaginal gels, intrauterine devices (IUD), and injections. Uses of progestin are:
birth control – contraceptives
Hormone replacement therap
uterine bleeding
arrest of menstruation
Endometrial hyperplasia, an abnormal thickening of the uterus wall
sexual desires loss
prevents miscarriage
used in the treatment of infertility treatment