[Galactorrhea and prolactin secretion in acromegaly]

Area of Science:

• Endocrinology
• Reproductive Medicine
• Oncology

Background:

• Acromegaly is a condition characterized by excessive growth hormone (GH) production, often leading to various hormonal imbalances.
• Lactorrhea, the inappropriate production of milk, can be a symptom associated with endocrine disorders like acromegaly.
• The interplay between pituitary hormones such as prolactin (PL), somatotropic hormone (STH), and gonadotropins (FSH, LH) is crucial in reproductive health and can be disrupted in acromegaly.

Purpose of the Study:

• To investigate the relationship between lactorrhea and baseline blood levels of key pituitary hormones (STH, PL, FSH, LH) in acromegaly patients.
• To assess the impact of thyrotropin-releasing hormone (TRH) stimulation on prolactin and thyrotropic hormone (TTH) secretion in active and inactive acromegaly.
• To determine the primary hormonal driver of lactorrhea in acromegaly and its potential association with tumor activity.

Main Methods:

• Hormone levels (STH, PL, FSH, LH) were measured in 62 untreated active acromegaly patients and 41 inactive, post-radiation therapy patients.
• Twenty active and six inactive acromegaly patients underwent assessment of TTH, PL, and STH secretion, both basally and after TRH stimulation.
• Lactorrhea prevalence was compared between active and inactive acromegaly groups and correlated with hormonal profiles.

Main Results:

• Lactorrhea was significantly more prevalent in women (60%) with active acromegaly compared to inactive disease (13.3%).
• Elevated baseline prolactin (PL) levels were observed in both active and inactive acromegaly groups, strongly correlating with lactorrhea.
• TRH stimulation significantly increased PL secretion in active acromegaly and remission stages, while TTH levels remained normal; STH secretion was independent of lactorrhea.

Conclusions:

• Increased prolactin (PL) secretion is the principal factor in the pathogenesis of lactorrhea associated with acromegaly.
• The study suggests that unresponsive PL secretion alongside absent TTH secretion in some lactorrhea patients may indicate tumor progression.
• Somatotropic hormone (STH) levels did not directly correlate with lactorrhea in acromegaly patients, irrespective of TRH stimulation.