Androgen and estrogen receptors in the developing mouse brain

Area of Science:

• Neuroendocrinology
• Developmental Neuroscience
• Molecular Endocrinology

Background:

• The developing brain is influenced by steroid hormones.
• Understanding steroid receptor dynamics is crucial for comprehending brain development and sexual differentiation.

Purpose of the Study:

• To characterize the binding of androgens (testosterone, DHT) and estradiol to brain cytosol receptors in immature mice.
• To investigate the developmental patterns and regional distribution of these steroid receptors.

Main Methods:

• Steroid binding assays using charcoal adsorption and glycerol gradient centrifugation.
• Scatchard plot analysis to determine receptor affinity and concentration.
• Regional analysis of receptor binding in specific brain areas (hypothalamus-preoptic area, cerebral cortex).

Main Results:

• Putative androgen and estradiol receptors (8S/5S) are present in immature mouse brain cytosol.
• Fetoneonatal estradiol binding protein (FEBP) complicates early estradiol binding measurements.
• DHT receptor concentration increases with age in female mouse brains and across various brain regions.
• Receptor affinities for DHT and estradiol are similar in male and female mice, with DHT having higher affinity.
• Regional differences in receptor concentration are observed, particularly for estradiol in the hypothalamus-preoptic area.

Conclusions:

• Immature mouse brains possess distinct androgen and estrogen receptors with specific binding characteristics.
• Developmental changes and regional variations in these receptors suggest a role in sexual differentiation of the brain.
• The high affinity for DHT may relate to its metabolic stability.