17a-OH-Progesterone [HRP]

Progesterone, also known as luteinizing hormone, is the main component of progesterone, which is produced primarily by the ovaries and the placenta in women, and by the adrenal cortex and testes in men. Progesterone, an intermediate product of steroid hormone synthesis, is metabolized in the body primarily by the liver and excreted in urine or bile. The main pathway for progesterone synthesis is the transfer of cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane facilitated by steroid hormone synthesis acute regulator proteins, and then cholesterol is converted to pregnenolone at the stromal surface of the inner mitochondrial membrane by cholesterol side-chain lysis enzymes, which is then transferred to the slippery endoplasmic reticulum, where it is converted to progesterone in the presence of 3β-hydroxysterols.

In early pregnancy, progesterone is mainly produced by the corpus luteum, which is succeeded by placental syncytiotrophoblasts after 8-10 weeks, so that progesterone levels reflect the function of the corpus luteum and placenta of ovarian pregnancy. It is usually believed that the progesterone produced by the corpus luteum before 7 weeks of pregnancy determines whether or not the pregnancy can continue. When for some reason the corpus luteum does not produce sufficient levels of progesterone, early spontaneous abortion may result. When women with anovulatory cycles have estrogen to stimulate the endometrium and no progesterone to regulate and organize the endometrium, it can lead to irregular bleeding, or periods that last longer than normal. Progesterone, on the other hand, is the first line of treatment in emergency situations when heavy menstrual bleeding occurs, limiting bleeding and improving a woman's quality of life. Progesterone also prevents or treats hyperplasia, atypical hyperplasia, and even well-differentiated endometrial cancer.

Figure 1. Fluctuations in progesterone levels during the menstrual cycle, pregnancy and mood changes
(Source: Sundström-Poromaa I, et al. 2020)

In addition to the role progesterone plays in female reproductive function, researchers have found that it can also affect male reproductive health. Progesterone is converted to androstenedione by 17α-hydroxylase and later to testosterone by 17β-hydroxysteroid dehydrogenase. Abnormal testosterone is often a major cause of male reproductive disorders. In addition, progesterone can also act directly on the testes, affecting male fertility by regulating sperm fertilization. Progesterone and its receptors are potential pathogenic hormones in benign prostatic hyperplasia and prostate cancer. High-dose progesterone activates classical and nonclassical androgen receptor target genes and promotes cancer cell proliferation via GATA-binding proteins, whereas 3β-hydroxysteroid dehydrogenase 1 inhibitors inhibit progesterone production and abrogate its oncogenic effects.

17a-OH-luteinizing hormone