17-Hydroxyprogesterone Unit Converter
Synonyms
17-OHP, 17-OH Progesterone, 17α-Hydroxyprogesterone (17α-OHP), Hydroxyprogesterone (OHP), 17 Alpha-hydroxyprogesterone, 17α-hydroxypregn-4-ene-3,20-dione
Units of Measurement
nmol/L, ng/mL, ng/dL, ng/100mL, ng%, ng/L, µg/L
Biological Significance
17-α-Hydroxyprogesterone (17-α-OHP) is a naturally occurring steroid hormone produced by both the adrenal cortex and the gonads. Although it exhibits minimal progestational activity, it is of significant clinical interest as the immediate precursor of 11-deoxycortisol (compound S). Since 11-deoxycortisol is synthesized through 21-hydroxylation of 17-α-OHP, measuring 17-α-OHP serves as a useful indirect indicator of 21-hydroxylase enzyme activity.
In congenital 21-hydroxylase deficiency—the most prevalent form of congenital adrenal hyperplasia (CAH)—17-α-OHP is secreted in markedly elevated amounts. It also tends to be moderately elevated in individuals with 11β-hydroxylase deficiency. For this reason, quantifying 17-α-OHP levels plays an important role in the initial diagnosis of CAH.
Physiological Variations
Adult Non-Pregnant Women
Among women of childbearing age, 17-α-OHP levels vary throughout the menstrual cycle. Concentrations are typically higher in the luteal phase than in the follicular phase due to parallel secretion with progesterone from the corpus luteum and maturing follicles. Diurnal variations also exist, with peak levels occurring between midnight and 8:00 AM, mirroring the circadian rhythm of cortisol production.
Adult Males
There is limited data on the physiological variability of 17-α-OHP concentrations in adult males.
Pregnancy and Neonates
In pregnant women and newborns, 17-α-OHP is synthesized in significant quantities by the fetus and adrenal glands. It enters both fetal and maternal circulation. Maternal concentrations rise sharply after 32 weeks of gestation, reaching approximately four times the basal levels by term.
Clinical Applications
1. Congenital Adrenal Hyperplasia (CAH)
The primary clinical use of 17-α-OHP measurement is in the diagnosis of CAH in newborns with ambiguous genitalia or in adolescent girls presenting with virilization. Because 17-α-OHP is a precursor of 11-deoxycortisol, basal concentrations are significantly elevated in patients with 21-hydroxylase deficiency, and to a lesser extent in those with 11β-hydroxylase deficiency. In most cases, a single baseline measurement is sufficient for diagnosis.
2. Late-Onset Adrenal Hyperplasia
17-α-OHP levels are also valuable in evaluating women with signs of androgen excess, where late-onset 21-hydroxylase deficiency may be suspected. This form of CAH can mimic polycystic ovarian syndrome (PCOS), and baseline 17-α-OHP levels are often within normal range. Diagnosis typically requires an ACTH stimulation test.
3. Other Uses
Although less common, 17-α-OHP assessment has been used in evaluating conditions such as acne vulgaris, male-pattern baldness, and some forms of unexplained infertility in both men and women. However, clinical experience with these applications remains limited.
Unit Conversion Tool
Use the SI Units Conversion Calculator to convert 17-Hydroxyprogesterone values between various units including:
- nmol/L, ng/mL, ng/dL, ng/100mL, ng%,
- ng/L, and µg/L
This tool provides an easy and accurate way to convert between traditional and SI units, aiding in clinical interpretation and standardization of lab results. Below is a reference table of conversion factors for 17-Hydroxyprogesterone:
| From | To | Conversion |
|---|---|---|
| nmol/L | ng/mL | × 0.33046 |
| nmol/L | ng/dL | × 33.046 |
| nmol/L | ng/L | × 330.46 |