<prompt> GnRH is a -PeptideAmineSteroidNone  <response>: Ans. is a i.e., Peptide o Three general classes of hormone exist: -1 Proteins and polypeptide 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, adreno- corticotropin hormone ACTH, prolactin, follicle stimulating hormone FSH, leutinizing hormone LH.Posterior pituitaryr:- Antidiuretic hormone ADHvasopressin, oxytocin.Thyroid gland :- CalcitoninPancreas :- Insulin, glucagon.Parathyroid ParathormonePlacenta Human chorionic gonadotropin HCG, Human somatomammotropin.Kidney Renin, erythropoietinHeartAtria! natriuretic peptide ANPStomach GastrinSmall intestine Secretin, Cholecystokinin CCKAdipocytes LeptinAngiotensin IISome of these peptide hormones are glycoproteins, i.e., they have sugar associated with proteins. Glyco- protein hormones are FSH, LH, TSH, human chorionic gonadotropin, erythropoietin.Steroid hormonesSteroid 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 T4 and Triiodothyronine T3.Adrenal medulla Norepinephrine Noradrenaline, Epinephrine adrenalineHypothalamus Dopamine or Prolactin inhibiting factor PIF. 