**Core Concept**
FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) are crucial gonadotropins produced by the anterior pituitary gland. These hormones play essential roles in regulating the reproductive cycle, particularly in the development and maintenance of the reproductive organs. The regulation of FSH and LH secretion is a complex process involving feedback mechanisms from the hypothalamus, pituitary gland, and gonads.

**Why the Correct Answer is Right**
The inhibition of FSH and LH secretion is primarily mediated by sex steroids, specifically estrogen and progesterone. In the female, high levels of estrogen inhibit the release of GnRH (Gonadotropin-Releasing Hormone) from the hypothalamus, which in turn reduces the secretion of FSH and LH from the anterior pituitary gland. In the male, testosterone inhibits the release of GnRH, leading to decreased FSH and LH secretion. This negative feedback loop helps maintain a delicate balance between gonadotropin secretion and sex steroid levels.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately represent the primary inhibitors of FSH and LH secretion.
**Option B:** This option is incorrect as it is not a known regulator of FSH and LH secretion.
**Option C:** This option is incorrect as it is not a primary inhibitor of FSH and LH secretion.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the regulation of FSH and LH secretion is a complex process involving feedback mechanisms. Understanding the role of sex steroids in inhibiting gonadotropin secretion is crucial for managing conditions such as polycystic ovary syndrome (PCOS) and hypogonadism.

**Correct Answer:** D.