VU1 CONTENTS 



II. The Digestion and Absorption of Fats in the Gastrointestinal Tract 



(continued) 



(e) Cell Permeability in Relation to Cholinesterases 44 



(f) Physiological and Pathological Factors Altering the Amount 



of Cholinesterases 46 



(g) Distribution of Cholinesterases 52 



a'. Cholinesterases in Blood 52 



b'. Cholinesterases in Brain and Nervous Tissue 53 



c'. Cholinesterases in Glandular Tissues 55 



d'. Cholinesterases in Miscellaneous Tissues 56 



e '. Cholinesterases in Snake Venom 57 



f '. Acetylesterase in Citrus 59 



(h) Preparation of Cholinesterases 59 



(i) Acetylcholine in Tissues 60 



d. Choline Acetylase 61 



(a) Introduction 61 



(b) Mechanism of Action 61 



(c) Distribution of Choline Acetylase 63 



(d) Factors Altering the Activity of Choline Acetylase 64 



e. Chlorophyllase 65 



f. Phytase 67 



3. The Role of Bile in Lipid Absorption 69 



(1) The Nature, Distribution, and Properties of the Bile Acids 70 



a. Distribution of the Bile Acids 70 



b. Conjugation of the Bile Acids 79 



c. Properties of the Bile Acids 85 



d. Synthesis of the Bile Acids 88 



e. Interrelations of the Bile Acids 88 



(a) Reduction of Ketocholanic Acids 89 



(b) Removal of Hydroxyl Groups 90 



(c) Oxidation of Hydroxy- to Keto-Acids 90 



(d) Change in Isomeric Form 91 



(2) The Action of Bile in Lipid Absorption 91 



a. Choleic Acids and Related Coordination Compounds 92 



(a) Discovery 93 



(b) General Properties 94 



(c) Occurrence and Types of Choleic Acids 94 



(d) Coordination Number 95 



(e) Apocholic Acid Complexes 104 



(f) Physical Properties of Choleic Acids 105 



(g) Factors Involved in the Formation of Choleic Acid 108 



(h) Types of Coordination Compounds of Bile Acids Other Than 



Choleic Acids 108 



(i) Physiological Importance of Choleic Acid Formation 108 



b. Circulation of the Bile Acids Ill 



(a) Absorption of the Bile Acids Ill 



(b) Reexcretion of the Bile Acids 113 



