Endocrine System Flashcards
Thyrotropin-releasing hormone (TRH)
Produced & released by: Hypothalamus
Target Cells: cells of anterior pituitary
that produce TSH
Actions: Stimulates cells of anterior pituitary to
make & release TSH
Stimuli for release: Low blood thyroid hormone, Cold, Pregnancy, High sympathetic inputs
Inhibited by: Negative feedback by thyroid
hormone
Solubility: water
Thyroid-stimulating hormone (TSH)
Produced & released by: cells of anterior pituitary
Target cells: cells of thyroid gland
Actions: Stimulates thyroid gland to make and
release TH (thyroid hormone)
Stimuli for release: TRH from hypothalamus
Inhibited by: Negative feedback by thyroid hormone on both anterior pituitary and hypothalamus
Solubility: water
Thyroid hormone (TH, T3 or T4)
Produced and released by: thyroid gland
Target cells: All cells of body
Actions: Baseline metabolic rate, Increases HR and body temp, Increases pump activity, Increases mitochondrial number, activity
Stimuli of release: TSH
Inhibited by: typical negative feedback
Solubility: water
Glucogan
Produced and released by: pancreas
Target cells: Muscle, liver, fat
Actions: Glycogen breakdown in muscle, Glycogenolysis, gluconeogenesis in liver, Fat lysis
stimuli: Low blood sugar, High sympathetic inputs, High blood amino acids
Inhibited by: typical negative feedback
Solubility: water
Insulin
Produced and released by: pancreas
Target cells: all cells (except neural)
Actions: Stimulates cells to uptake glucose, Stimulates liver, cells to make glycogen, Stimulates glucose conversion to fat; fat storage, Amino acid uptake and protein formation
Stimuli: High blood sugar, High parasympathetic inputs, High blood amino acids or fatty acids, Any hyperglycemic agent
Inhibited by: Typical negative feedback
Solubility: water
Gonadotropin-releasing
hormone
(GnRH)
Produced & released by: Hypothalamus
Target cells: Cells of anterior pituitary that produce FSH and LH
Actions: Stimulates cells of anterior pituitary to
make and release FSH and LH
Stimuli: Puberty, Low sex hormones
Inhibited by: Negative feedback by estrogen and testosterone, FSH, LH on hypothalamus
Solubility: water
Follicle-stimulating
hormone
(FSH)
Produced & released by: cells of anterior pituitary
Target cells : Gonads, Testes: sustentactular cells, Ovaries: follicle cells
Actions: - Stimulates ovaries, testes to produce gametes
- Stimulates ovaries to make follicles, secrete estrogen
Stimuli: GnRH from hypothalamus, triggered by puberty
Inhibited by: Negative feedback by estrogen and testosterone on hypothalamus and anterior pituitary
Solubility: water
Lutenizing hormone
(LH)
Produced & release by: cells of anterior pituitary
Target cells: Gonads, Testes: interstitial (Leydig) cells, Ovaries: follicle cells and eggs
Actions: Stimulates egg division, ovulation and
secretion of estrogen and progesterone by ovaries, Stimulates secretion of testosterone by testes
Stimuli: GnRH from hypothalamus, triggered by puberty
Inhibited by: Negative feedback by estrogen
and testosterone on hypothalamus and anterior pituitary
Solubility: water
Testosterone
Produced & released by: Leydig (interstitial) cells from testes
Target cells: All cells of body, Sustentactular (Sertoli) cells
Actions: Sperm formation, Secondary sexual characteristics, body growth, sex organ maintenance, Libido, CNS health
Stimuli: LH
Inhibited by: typical negative feedback
Solubility: fat
Estrogen
Produced & released by: Follicle cells of
ovaries, Placenta
Target cells: all cells of body, uterus, ovary
Actions: Promotes ovulation through positive feedback on anterior pituitary and hypothalamus, Regulates uterine cycle, proliferative phase, Secondary sexual characteristics (increased bone mass, fat deposition,
development of sexual organs)
Stimuli: LH
Inhibited by: negative feedback
Solubilty: fat
Progesterone
Produced and released by: Follicle cells of ovary
(corpus luteum), Placenta
Target cells: Uterus, breasts
Actions: “Pregnancy hormone”; regulates
secretory phase of uterine cycle, At breasts, development of milk producing tissue (but not milk
production)
Stimuli: LH
inhibited by: negative feedback
Solubility: fat
Inhibin
Produced & release by: cells of testes and ovaries
Target cells: Hypothalamus, Cells of anterior pituitary that make FSH
Actions: Inhibit production of GnRH or FSH or LH
Stimuli: High levels of testosterone/ estrogen/ progesterone
Inhibited by: negative
Solubility: water
Parathyroid hormone
(PTH)
Produced & released by: Parathyroid gland
Target cells: Bone, GI tract, Kidney
Actions: Stimulates osteoclasts to destroy bone
(releasing Ca2+ into blood), Stimulates absorption of Ca2+ into GI tract, Inhibits Ca2+ loss in urine
Stimuli: Low blood Ca2+
Inhibited by: negative feedback
Solubility: Water
Calcitonin
Produced & released by: thyroid gland
Target cells: Bones, GI tract, Kidney
Actions: Stimulates osteoblasts to build bone
(removing Ca2+ from blood), Inhibits absorption of Ca2+ into GI tract, Promotes Ca2+ loss in urine
Stimuli: High blood Ca2+
Inhibited by: negative feedback
solubility: water
Growth hormone
releasing hormone
(GHRH)
Produced & released by: Hypothalamus
Target cells: Cells of anterior pituitary that make GH
Actions: Stimulates cells of anterior pituitary to
make and release GH
Stimuli: Pulsatile pattern, with increases associated with sleep, exercise, or protein starvation
Inhibited by: negative feedback
Solubility: water
