Hypothalamic control of anterior pituitary function: a history

Area of Science:

• Neuroendocrinology
• Reproductive Biology
• Neuroscience

Background:

• Neurohumoral control of anterior pituitary function was pioneered by Geoffrey Harris.
• The medial preoptic area (MPOA) was identified as a key brain region controlling gonadotrophic hormone release.
• Gonadotropin-releasing hormone (GnRH) was later isolated and synthesized.

Purpose of the Study:

• To investigate the neuroanatomical pathways controlling gonadotrophic hormone synthesis and release.
• To elucidate the role of GnRH in reproductive function.
• To explore the recent findings on kisspeptin's involvement in GnRH neuron regulation.

Main Methods:

• Electrical stimulation, lesioning, and fibre tract cutting to identify brain control areas.
• Use of antibodies against GnRH to locate neurons and measure hormone levels in portal blood.
• Studies on hypogonadal (hpg) mice with a natural GnRH gene knockout, including hormone injections, gene replacement, and neural grafting.
• Application of modern molecular biology techniques to investigate kisspeptin and its receptor (GPR54).

Main Results:

• The MPOA was confirmed as a major integrating center, with projections to the median eminence.
• GnRH was detected in high levels in portal blood, confirming its role.
• Studies in hpg mice demonstrated the essential role of GnRH in reproduction.
• Kisspeptin and its receptor (GPR54) were identified as crucial modulators of GnRH neurons.

Conclusions:

• The MPOA is a critical brain region for neurohumoral control of reproduction via GnRH.
• GnRH is indispensable for reproductive function, as shown by studies in hpg mice.
• Kisspeptin signaling represents a significant advancement in understanding the hypothalamic modulation of reproduction.