xvill CONTENTS 



IX. The IVIetabolisni and Nutritional Value of the Carotenoids and 

 Vilaniins A ^continued) 



a. Prenatal Effects of Vitamin A Deficiency 594 



1). Postnatal Effects of Vitamin A Deficiency 594 



(a) Effect of Epithelial Tissues and on Organs 595 



a'. Fjffect on the Eyes 595 



b'. Effect on the Respiratory Tract 596 



c'. Effect on the Gastrointestinal Tract 596 



d'. Effect on the Genitourinary Tract 596 



e'. Effect on the Skin 597 



f '. Effect on the Teeth 598 



(b) Effect on the Bones 598 



(3) Deficiency Symptoms in Man 599 



a. Introduction 599 



b. Experimental Avitaminosis A in Man 600 



c. Effects of Vitamin A Deficiencj^ in Man 601 



(a) Night Blindness 601 



(b) Xerophthalmia and Keratomalacia 601 



(c) Metaplasia of Epithelia 602 



(d) Cutaneous Lesions 603 



1 1 . Hypervitaminosis A 604 



(1 ) Introduction 604 



(2) Symptoms of Hypervitaminosis A in Animals 606 



a. Skin Symptoms 606 



b. Skeletal Lesions 607 



c. Hemorrhage and Inflammation of Mucous Membranes 608 



d. Endocrine Symptoms 608 



e. Other Effects of Hypervitaminosis A 610 



(3) Symptoms of Hypervitaminosis A in Man 610 



(4) The Level of Vitamin A Intake Which Causes Toxicity 611 



a. Acute Toxicity in the Rat 611 



b. Chronic Toxicity in the Rat 612 



(a) The Level of Toxicity in Young Rats 612 



(b) Age As a Factor in Toxicity 613 



(c) Relative Toxicity When Vitamin A Is Administered Orally 



or Parenterally to Rats 613 



(d) Toxicity in Animals Other Than the Rat 613 



c. Acute and Chronic Toxicity in Man 614 



(5) The Interaction of Excess Vitamin A with Other Vitamins and 



with Hormones 615 



a. Interaction with Thyroxine 615 



b. Interaction with Calci\im and Phosphorus 616 



c. Interaction with the Vitamin B Complex 616 



d. Interaction with Ascorbic Acid 616 



e. Interaction with Vitamin D 618 



f. Interaction with Vitamin K 618 



