Endocrinology: study of hormones Gland Transport Target Cell Hormone General Features of the endocrine system:

Synthesis and secretion of a protein hormone NUCLEUS DNA MEMBRANE CELL TRANSCRIPTION RNA PROCESSING RNA TRANSPORT mRNA TRANSLATION PROTEIN SYNTHESIS mRNA PROTEIN PROCESSING SECRETION BY EXOCYTOSIS PACKAGED IN A SECRETORY VESICLE Protein hormone secretion can be: releasing hormone

Synthesis of thyroid hormones Cell membrane cytoplasm Golgi apparatus CH2 OH CH2 OH vessicle thyroglobulin I I I I CH2 OH I I CH2 OH I I enzymes lysozyme OH I I CH2 O I I OH I I CH2 O I I OH I I CH2 O I I I I I I Tropic hormone

Synthesis and secretion of a Steroid hormone NUCLEUS MEMBRANE CELL SECRETION Steroid hormone secretion must be: constitutive It cannot be regulated HO C-CH 2 -C 5 H 11 CH 3 Cholesterol tropic hormone Cholesterol store in cell Mitochondria It also may occur in the endoplasmic reticulum enzymes Protein synthesis for: -Cell growth -cell division -Enzymes for mitochondria steroid

Steroid Biosynthesis