Question

The mechanism of action of Saheli which makes it a chemical contraceptive is:

• A. It modifies estrogen receptors in the uterus
• B. It modifies the estrogen receptors in the ovary
• C. It modifies the progesterone receptors in the uterus
• D. It modifies the progesterone receptors in the ovary

Answer 1

The correct option is A It modifies estrogen receptors in the uterus

The chemical method of contraceptives that are used to prevent pregnancy operate broadly by two methods- either they disturb the normal hormonal cycle of the female to prevent ovulation and implantation (steroidal chemicals) or they modify the hormone receptors in the uterus to prevent implantation (non steroidal chemicals). The steroidal chemicals include the use of synthetic forms of natural steroid hormones, progesterone and estrogen.
The non steroidal chemicals include ormeloxifene (or centchroman). It is one of the Selective Estrogen Receptor Modulators (SERM), a class of medication which acts on the estrogen receptors. The SERM modify the estrogen receptors present in the uterus, due to which the estrogen cannot bind to them and doesn’t bring about any changes necessary for implantation. So, it prevents implantation. Ormeloxifene is a chemical which is marketed under the brand name of ‘Saheli’. It specifically targets the estrogen receptors.
Estrogen receptors are formed in the ovary only after the development of follicles. The development of follicles leads to the natural synthesis of estrogen after which the ovary develops receptors. SERM is not known to target the estrogen receptors in the ovary.
SERM doesn’t target the receptors for any other hormone. So progesterone receptors on any organ are not affected.