Maturation of synapses in chicken forebrain.

The detergent treatment used to prepare synaptic junction and post-synaptic density (PSD) fractions cause a much greater disruption and solubilization of the PSD in young chicken forebrain than in adult forebrain. The disruption is manifested as a large decrease in the amount of the major PSD protein present in the isolated fractions. This 'fragility' of the PSD persists throughout the first month after hatching and gradually disappears during the second month. Artificial elevation of systemic testosterone levels speeded up this maturation of the PSD but only if the hormone was injected during the second month.