Pineal Compounds Alter Prolactin Release from Bovine Pituitary Cells 1

Abstract

Summary

Compounds native to the pineal were screened using a bovine pituitary cell culture system to investigate their effects on pituitary prolactin secretion. Thyrotropin releasing hormone (10⁻¹¹-10⁻⁷ M) and arginine vasotocin (10⁻¹⁰-10⁻⁶ M) increased prolactin in medium and this increase was linearly related to increasing log concentrations of each peptide. In contrast, dopamine (10⁻⁹-10⁻⁷ M) and norepinephrine (10⁻¹⁰-10⁻⁸ M) decreased prolactin accumulation in medium and decrease was linearly related to increasing log concentrations of catecholamines. Serotonin (10⁻¹⁰-10⁻⁶ M) also inhibited prolactin release and decrease was linearly related to increasing log concentrations of serotonin. Melatonin, 5-hydroxytryptophol and 5-methoxytryptophol had no direct effect on pituitary prolactin secretion. We conclude that compounds indigenous to the pineal have the potential to regulate PRL secretion from the pituitary.