Role of Adenohypophysotropic Neurohormones in Endocrine Paraadenohypophysial Regulation of Peripheral Target Organs in Rat Ontogeny.

We tested the hypothesis that brain-derived chemical stimuli contribute to direct endocrine regulation of peripheral organs during ontogeny before blood-brain barrier closure. Dopamine and gonadotropin-releasing hormone present in high concentration in peripheral blood only before blood-brain barrier closure were chosen as the chemical stimuli. It was shown than dopamine in concentrations equal to its level in the peripheral blood inhibits prolactin secretion in organotypic culture of the pituitary gland from newborn rats via specific receptors. Experiments on organotypic culture of neonatal rat testicles showed that gonadotropin-releasing hormone stimulates testosterone secretion via specific receptors. We proved that chemical stimuli entering common circulation from the brain before blood-brain barrier closure could exert direct endocrine effect on peripheral organs.