Hormonal Biochemistry. Flashcards
what is a hormone
Hormones are biologically active chemical messengers, which are released into the humors (blood, lymph, saliva, and CSF) by the endocrine glands and transported to specific target tissues, where they exert/ stimulate their physiological or biochemical activity. As universal regulators of the body’s functioning, hormones play an important role in maintaining homeostasis. They influence all essential life processes, such as growth, metabolism, development, immune defence, reproduction, behaviour and adaptation to the conditions of existence.
how are hormones classified
- By Proximity of their site of synthesis to their site of action,
- By their chemical structure,
- By their degree of solubility in an aqueous medium
list the three classes of hormones based on their proximity of their site of synthesis to their site of action
-Autocrine hormones
-Paracrine hormones
-Endocrine hormones
what are autocrine hormones
they are hormones that act on the same cells that synthesize them
what are paracrine hormones
they are hormones that are synthesized very close to their site of action
what are paracrine hormones
they are hormones that are synthesized very close to their site of action
what are endocrine hormones
They are synthesized by endocrine glands and transported in the blood to target cells that contain the appropriate receptors
what are the classifications of hormones based on chemical structure
-Peptides/protein hormone
-amino acid derivatives
-fatty acid derivatives
-steroid hormones
what are the peptide hormones
- They are synthesized as peptides or large polypeptides
precursors that undergo processing before secretion;
Examples: - Thyrotropin Releasing Hormone (TRH), made up of
three amino acid residues; - Insulin, made up of 51 amino acid residues;
- Pituitary Gonadotrophins, made up of large
Glycoproteins with subunits
examples of peptide hormones:
-Hormones of the pancreas: Glucagon, Insulin
-Pituitary gland:
-Anterior: FSH,TSH,LH,ACTH, GH, PROLACTIN
-Posterior: Oxytocin, ADH (vasopressin)
-Pars intermedia: α-MSH, β-MSH
-Hormones of the parathyroid: Parathormone
-Hormones of the GIT: Gastrin, cholecystokinin, pancreozymin, enterogastrone, enterokinin, Hepatokinin, Duicrinin, Villikrinin, Parotin
-Hormone of the corpus luteum: Relaxin
examples of “amino acid derivatives” hormones
-Thyroid gland hormones: Triiodothyronine (T3), Thyroxine (T4),
-Adrenal medulla: Dopamine, Norepinephrine, Epinephrine
examples of fatty acid derivative hormones
THE EICOSANOIDS:
-prostaglandins,
-thromboxanes, and
-leukotrienes
examples of steroid hormones
ADRENAL CORTEX.
-Mineralocorticoids
1. Aldosterone
2. 11deoxycorticosterone
-Glucocorticoids
1. Cortisol
2. Corticosterone
-Sex hormones
1. Androgens
2. Estrogen
3. Progesterone
