Changes of prolactin secretion following long-term danazol application

Area of Science:

• Endocrinology
• Reproductive Medicine
• Pharmacology

Background:

• Endometriosis and fibrocystic mammary disease are common gynecological and breast conditions.
• Hormonal imbalances, particularly involving prolactin and gonadotropins, are implicated in these conditions.
• Danazol, a synthetic steroid, has been used to treat these conditions, but its precise hormonal mechanisms require elucidation.

Purpose of the Study:

• To investigate the effects of oral danazol on prolactin and gonadotropin secretion in patients with endometriosis or fibrocystic mammary disease.
• To evaluate hormonal changes during and after danazol therapy.
• To correlate hormonal changes with the therapeutic effects of danazol.

Main Methods:

• Ten patients received oral danazol (4 x 200 mg daily) for six months.
• Serum levels of prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, and progesterone were measured.
• Hormonal assessments were conducted before therapy, at intervals during treatment (1, 3, 6 months), and 4 weeks post-treatment, including stimulated tests with metoclopramide and LH-releasing hormone (LH-RH).

Main Results:

• Danazol treatment led to a continuous decrease in basal and stimulated prolactin levels, reaching early follicular phase concentrations.
• Estradiol levels decreased, and progesterone secretion was absent during danazol therapy.
• Basal and LH-RH-stimulated LH levels remained largely unchanged, while basal and stimulated FSH levels significantly increased.

Conclusions:

• The reduction in serum and pituitary prolactin may explain danazol's beneficial effects on fibrocystic mammary disease.
• The selective increase in FSH secretion during danazol treatment is observed but its mechanism, potentially related to reduced follicular inhibin feedback, is unclear.
• Hormonal parameters normalized within four weeks of discontinuing danazol therapy.