Animal Physiology Hormones

Gonadotropin Releasing Hormone

Origin: Hypothalamus, Stimulus: Low levels of sex hormones, onset of puberty, Effect:: Stimulates release of follicle-stimulating hormone and luteinizing hormone

Thyrotropin Releasing Hormone

Origin: Hypothalamus, Stimulus: low thyroid hormone levels, low metabolic rate, cold stress, Effect: Stimulates the release of thyroid-stimulating hormone

Corticotropin Releasing Hormone

Origin: Hypothalamus, Stimulus: Physical or emotional stress, low cortisol levels, Effect: Stimulates release of adrenocorticotropic hormone

Prolactin Inhibiting Hormone

Origin: Hypothalamus, Stimulus: High prolactin levels, Effect: Inhibits release of prolactin

Growth Hormone Releasing Hormone

Origin: Hypothalamus, Stimulus: low growth hormone levels, hypoglycemia, deep sleep, exercise, Effect: Stimulates release of growth hormone

Somatostatin

Origin: Hypothalamus, Stimulus: High growth hormone or insulin like growth factor, Effect: Inhibits release of growth hormone or TSH

Vasopressin

Origin: Posterior Pituitary, Stimulus: High blood osmolarity, low blood volume, Target: Kidneys, blood vessels, Effect: increases water reabsorption to decrease urine volume and conserve body water.

Oxytocin

Origin: Posterior Pituitary, Stimulus: Uterine stretching during labor, infant suckling, Target: Uterus, Mammary glands, Effect: Stimulates uterine contractions, triggers milk ejection.

Thyroid-Stimulating Hormone

Origin: Anterior Pituitary, Stimulus: Thyrotropin Releasing Hormone, Target: Thyroid gland, Effect: Stimulates synthesis and release of thyroid hormones (T3 and T4)

Adrenocorticotropic Hormone (ACTH)

Origin: Anterior Pituitary, Stimulus: Corticotropin releasing hormone, Target: Adrenal Cortex, Effect: Stimulates the release of glucocorticoids

Growth Hormone

Origin: Anterior Pituitary, Stimulus: GHRH, low blood sugar, Target: Liver, bone, skeletal muscle, cartilage, and general body tissues, Effect: Promotes growth and protein synthesis via insulin like growth factors (IGFs)

Prolactin

Origin: Anterior Pituitary, Stimulus: Decrease in prolactin inhibition hormone, Target: mammary glands, Effect: Stimulates mammary gland development and milk production

Follicle Stimulating Hormone

Origin: Anterior Pituitary, Stimulus: Gonadotropin releasing hormone, Target: Gonads, Effect: In females, stimulates ovarian follicle maturation and estrogen production, in males, stimulates sperm production

Luteinizing Hormone

Origin: Anterior Pituitary, Stimulus: Gonadotropin releasing hormone, Target Gonads, Effect: In females, triggers ovulation and stimulates the corpus lute to produce progesterone, in males, stimulates interstitial cells to produce testosterone

Thyroid Hormone

Origin: Thyroid Follicular Cells, Stimulus: Thyroid Stimulating Hormone, Target: Nearly all body cells, Effect: Increases basal metabolic rate, regulates tissue growth, essential for nervous system development

Calcitonin

Origin: Thyroid Parafollicular Cells, Stimulus: High blood calcium levels, Target: Bones, Kidneys, Effect: Inhibits osteoclasts and simulates Calcium excretion by kidneys to lower blood calcium levels

Parathyroid Hormone

Origin: Parathyroid Gland, Stimulus: Low blood calcium levels, Target: Bones, Kidneys, Small Intestine, Effect: Activates osteoclasts, increases renal calcium reabsorption to raise calcium levels

Cortisol

Origin: Adrenal Cortex, Stimulus: ACTH, long term stress, Target: Liver, muscle, adipose tissue, immune system, Effect: Promotes gluconeogenesis and glycogen synthesis, mobilizes fatty acids and amino acids, suppresses immune response and inflammation

Aldosterone

Origin: Adrenal Cortex, Stimulus: Angiotensin II, high blood potassium, low blood sodium, or a drop in blood pressure, Target: Kidneys, Effect: Increases sodium and water reabsorption, increase potassium excretion into urine, helps raise blood volume and blood pressure.

Insulin

Origin: Pancreas, Stimulus: High blood glucose levels, parasympathetic nervous system activation, Target: Liver, skeletal muscle, adipose tissue, Effect: Enhances cellular uptake of glucose, promotes glycogen, fat, and protein synthesis, lowers blood glucose levels

Epinephrine/Norepinephrine

Origin: Adrenal Medulla, Stimulus: Sympathetic nervous system activation, Target: Heart, blood vessels, bronchioles, liver, and adipose tissue, Effect: Increases heart rate, blood pressure, and metabolic rate, dilates airway , redirects blood flow to muscles, elevate blood glucose levels

Glucagon

Origin: Pancreas, Stimulus: Low blood glucose levels, sympathetic nervous system activation, Target: Liver, Effect: Stimulates glycogenolysis and glyconeogenesis, raises blood glucose levels

Estrogen

Origin: Ovarian follicles, Stimulus: Follicle stimulating hormone and Luteinizing hormone, Target: Uterus, vagina, breasts, and general body tissue, Effect: Stimulates development of female secondary sex characteristics, regulates menstrual cycle, endometrial growth

Progesterone

Origin: Ovary, Stimulus: Luteinizing Hormone, Target: Uterus, mammary gland, Effect: Prepares the endometrium for embryo implantation, maintains uterine lining, inhibits contractions

Testosterone

Origin: Interstitial cells of the testes, Stimulus: Luteinizing hormone, Target: male reproductive organs, bones, muscle, vocal cords, Effect: Male secondary sex characteristics

Melatonin

Origin: Pineal Gland, Stimulus: Darkness, Target: Hypothalamus and master biological clock, Effect: Regulates sleep wake cycles

Thymosin/Thymulin/Thymopoietin

Origin: Thymus Gland, Stimulus: Loan signals during early development and immune system development, Target: lymphocytes (white blood cells), Effect: Promotes the development, maturation, and immunological competence of T cells.