EFFECTS OF THE PINEAL GLAND IN UNILATERALLY ADRENALECTOMIZED RATS

Abstract

ABSTRACT The following experiments were undertaken to determine the effects that the pineal secretory substance might have on compensatory adrenal hypertrophy and corticosterone plasma levels in unilaterally adrenalectomized rats. It was demonstrated that blinded animals and animals administered with a bovine pineal extract exhibited a reduction in the percentage compensatory adrenal hypertrophy, a reduction in the thickness of the zona fasciculata, and a reduction in the plasma corticosterone level. These inhibitory effects were reversed by pinealectomy and ACTH injections, suggesting that the pineal gland, acting as a mediator for environmental lighting, might influence synthesis and/or release of ACTH.