Ensuring Gym Success: Dianabol Uses & Dosage Explained- Read Now!


1 – What Is 5‑α‑Reductase?


5‑α‑reductase is an enzyme complex that converts testosterone into its more potent androgen, dihydrotestosterone (DHT).

Two main isoforms exist in humans – type I and type II – which differ in tissue distribution and catalytic efficiency.

The reaction reduces the double bond between carbon‑4 and 5 of the steroid backbone, giving DHT a higher affinity for the androgen receptor.



---




2 – Where Is It Found?



Tissue Isoform predominance Functional significance


Prostate (epithelial & stromal cells) Type II Drives growth; essential in benign prostatic hyperplasia and prostate cancer.


Skin (keratinocytes, sebaceous glands) Both I & II Influences hair follicle cycling, sebum production, epidermal barrier formation.


Testis (Leydig cells) Type II Generates DHT for male sexual differentiation.


Brain (certain nuclei) Type I Modulates neurosteroid actions; may affect mood and cognition.


Kidney & adrenal glands Both Minor roles in local androgen metabolism.


---




2. Physiological Functions



2.1 In Skin



Hair Follicle Cycle: DHT stimulates the anagen phase but, after prolonged exposure, induces follicular miniaturization leading to androgenetic alopecia (AGA).


Sebaceous Gland Activity: Enhances sebum production; hypersecretion is linked to acne vulgaris.


Keratinocyte Proliferation & Differentiation: Influences epidermal turnover.




2.2 In Reproductive Tissues



Male Development: Essential for the formation of testes, seminal vesicles, and prostate during embryogenesis.


Female Reproduction: Plays a role in ovarian follicle maturation and uterine receptivity.




2.3 Other Physiological Roles



Bone Remodeling: Affects osteoblast activity.


Cardiovascular System: Modulates vascular smooth muscle cell proliferation.







4. Clinical Conditions Associated with Androgen Imbalance



Condition Key Pathophysiology Typical Presentation


Polycystic Ovary Syndrome (PCOS) Excess ovarian androgen production; insulin resistance amplifies LH secretion → ↑ androstenedione, testosterone Hirsutism, acne, anovulation, infertility


Androgenetic Alopecia Sensitivity of scalp follicles to DHT (5α-reductase conversion) leading to miniaturization Male pattern baldness, female pattern thinning


Congenital Adrenal Hyperplasia (CAH) 21‑hydroxylase deficiency → cortisol ↓; aldosterone ↓; excess androgen precursors Ambiguous genitalia in females, early virilization


Testicular or Ovarian Tumors Overproduction of testosterone or androstenedione by Leydig or theca cells Hyperandrogenic symptoms, irregular cycles


Cushing’s Syndrome Excess cortisol (adrenal tumor or ectopic ACTH) → secondary hyperandrogenism Hirsutism, acne, menstrual disturbances


---




3. How to Approach an Irregular Cycle in a Woman with Hyperandrogenemia




Take a Detailed History


- Age of menarche, cycle length, duration of bleeding or spotting, presence of amenorrhea.
- Onset and pattern of hirsutism, acne, alopecia, weight changes.
- Use of hormonal contraceptives or other medications.
- Family history of PCOS, thyroid disease, adrenal disorders.





Physical Examination


- BMI; waist‑to‑hip ratio.
- Hirsutism score (Ferriman–Gallwey).
- Signs of virilization: deepening voice, clitoromegaly.
- Skin exam for acne, acanthosis nigricans.





Laboratory Evaluation


Baseline (after overnight fast or early in cycle if possible):

| Test | Rationale |
|------|-----------|
| LH, FSH | Evaluate gonadotropin profile; LH/FSH ratio >2 suggests PCOS |
| Testosterone, free testosterone | Detect hyperandrogenemia; normal vs high |
| DHEA‑S | Elevated in adrenal disorders (e.g., congenital adrenal hyperplasia) |
| 17‑α‑hydroxyprogesterone (optional if suspicion of CAH) | Screening for CAH |
| Estradiol | Assess estrogen status |
| Progesterone | Evaluate luteal phase function |
| AMH | Elevated in PCOS; may aid diagnosis |
| Fasting glucose, HbA1c | Screen for insulin resistance / diabetes |
| Lipid panel (total cholesterol, LDL, HDL, triglycerides) | Metabolic risk assessment |
| Thyroid stimulating hormone (TSH), free T4 | Rule out thyroid dysfunction |



Timing considerations:





Menstrual cycle:


- If the patient is in the luteal phase (≈days 20‑28 of a 28‑day cycle), serum progesterone should be >5 ng/mL. A low progesterone indicates early follicular phase or anovulation.

- Estradiol levels are usually low (