[Ontogenesis of gonadotropic cells].

Area of Science:

• Reproductive Endocrinology
• Developmental Biology
• Fetal Physiology

Background:

• Gonadotrophs are key cells in the pituitary gland responsible for producing luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
• The precise timing and regulation of gonadotroph development during gestation are critical for reproductive health.
• Previous studies suggested a role for gonadoliberin (GnRH) in gonadotroph function, but its role in differentiation needed further investigation.

Purpose of the Study:

• To investigate the early development and differentiation of gonadotrophs in human and rat fetuses.
• To elucidate the role of gonadoliberin (GnRH) and other factors in the differentiation of pituitary gonadotrophs.

Main Methods:

• Detection and characterization of gonadotrophs in human and rat fetuses at various gestational stages.
• Organ culture of rat adenohypophysial primordia.
• In vitro studies using GnRH, insulin, and transferrin to assess their effects on gonadotroph differentiation.

Main Results:

• Human gonadotrophs were detected at 8 weeks gestation, synthesizing the alpha subunit of glycoprotein hormones throughout gestation.
• Rat gonadotrophs appeared at 17 days gestation; encephalectomy did not affect their development.
• Organ culture of rat pituitary primordia showed that GnRH, in synergy with insulin and transferrin, induced gonadotroph differentiation.
• Fetal hypothalamic GnRH and pituitary GnRH receptors were present from 12 days gestation in rats.

Conclusions:

• GnRH plays a crucial role in the differentiation of pituitary gonadotrophs, particularly in synergy with insulin and transferrin.
• While GnRH is present early in human fetal development, its specific role in gonadotroph differentiation requires further study.
• These findings provide insights into the developmental endocrinology of the reproductive axis.