<prompt> Which of the following is an amine hormone -TSHT4InsulinFSH  <response>: Ans. isb i.e., T4o Three general classes of hormone exist : -Proteins and polypeptideMost of hormones in the body are polypeptides and proteins. In general, polypeptides writh 100 or more aminoacids are called proteins, and those with fewer than 100 amino acids are referred to as peptides.Proteins and peptide hormones are synthesized on the rough ER. They are usually synthesized first as larger proteins precursors that are not biologically active preprohormone and cleaved in the ER to form smaller prohormones. These are then transferred to the Golgi apparatus for packing into secretory vesicles. In this process, enzymes in the vesicles cleave the prohormones to produce smaller, biologically active hormones and inactive fragments. Vesicles are stored into cytoplasm and secretion of the hormones occur by exocytosis.The peptideprotein hormones are :-Hypothalamus Thyrotropin releasing hormone TRH, corticotropin-releasing hormone CRH, Growth-hormone releasing hormone GHRh, Growth hormone inhibitory hormone GHIn, i.e., somatostatin, Gonadotropin-releasing hormone GnRH.Anterior pituitary Growth hormone, thyroid stimulating hormone THS or thyrotropin, adrenocorticotropin hormone ACTH, prolactin, follicle stimulating hormone FSH, leutinizing hormone LH.Posterior pituitary ; - Antidiuretic hormone ADHvasopressin, oxytocin.Thyroid gland : - CalcitoninPancreas : - Insulin, glucagon.Parathyroid : - ParathormonePlacenta : - Human chorionic gonadotropin HCG, Human somatomammotropin.Kidney : - Renin, erythropoietinHeart: - Atrial natriuretic peptide ANPStomach : - GastrinSmall intestine : - Secretin, Cholecystokinin CCKAdipocytes : - LeptinAngiotensin IISome of these peptide hormones are glycoproteins, i.e., they have sugar associated with proteins. Glycoprotein hormones are FSH, LH, TSH, human chorionic gonadotropin, erythropoietin,Steroid hormonesThese hormones are synthesized from cholesterol. Once they are synthesized, they are simply diffuse across the cell membrane because they are lipid soluble and enter the interstitial fluid and then the blood. Thus, they are not stored.Steroid hormones are : -Adrenal cortex : - Cortisol Glucocorticoids, Aldosterone mineralocorticoids.Gonads : - Testosterone, estrogen, progesterone.Kidney : - 1, 25 - DihydroxycholecalciferolAmine hormonesThese hormones are derivatives of amino acid tyrosine. These hormones are : -Thyroid gland : - Thyroxine T4and Triiodothyronine T3.Adrenal medulla : - Norepinephrine Noradrenaline, Epinephrine adrenalineHypothalamus : - Dopamine or Prolactin inhibiting factor PIF 