GnRH is a -

Ans. is 'a' i.e., Peptide o Three general classes of hormone exist: -1) Proteins and polypeptide# The peptide/protein 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 (ADH)/vasopressin, oxytocin.Thyroid gland :- CalcitoninPancreas :- Insulin, glucagon.Parathyroid ParathormonePlacenta Human chorionic gonadotropin (HCG), Human somatomammotropin.Kidney Renin, erythropoietinHeartAtria! natriuretic peptide (ANP)Stomach GastrinSmall intestine Secretin, Cholecystokinin (CCK)Adipocytes 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 (adrenaline)Hypothalamus Dopamine or Prolactin inhibiting factor (PIF).