Other hormones Flashcards
Insulin
- Produced by the pancreatic β cells
- Helps regulate blood glucose levels by LOWERING blood glucose levels.
Glucagon
- Produced by the pancreatic α cells
- Helps regulate blood glucose levels by RAISING blood glucose levels.
Insulin
hypoglycemic agent
❖The following hormones RAISE blood glucose levels:
- Glucagon
- Cortisol
- Epinepherine
- Thyroxine
- GH/somatotropin
Mature Insulin
- Insulin start as the single chain Proinsulin
- Poly peptide with two subunits (α&β)
- During Storage, C-peptide is removed
- No evidence for cleavage after secretion
Stimuli for Insulin secretion
- Blood Glucose
- Amino acids: All AA are not equal, Arginine is best
- Autonomic influences: vagal stimulation increases insulin secretion
- Paracrine or Intra Islet Control: Somatostain (δ cell) inhibits the secretion of both
insulin and glucagon.
Effects of Insulin
- Transport of Glucose into cells by facilitate diffusion
- Glucose utilization
- Glycogen synthesis
- AA transport by an active transport mechanism
- Protein synthesis
- FA transport
- Lipogenesis
- K+ & Mg++ transport
Tissue-specific effects of Insulin
❖Muscle: stimulate glycogen & protein synthesis
❖Adipose: stimulate lipogenesis & inhibits lipolysis
❖Liver: stimulate glycogen synthesis (first), then lipogenesis
Stimuli for the release of glucagon
- Plasma glucose:
- Amino acid: An increased plasma amino acid stimulates an
increase in glucagon release. - Autonomic nervous system
- Circulating ketones
Effects of glucagon
- Glycogenolysis (primarily in liver)
- Gluconeogenesis
- Hormone sensitive lipase
- Stimulate insulin release
- Has inotropic effect on the heart
Serotonin Active form
5-hydroxytryptamine
Serotonin serves as a
Neurotransmittor and as * as a modulator of vascular & GI functions
Serotonin is produced
Serotonin produced in the:
* Intestinal enterochromaffin cells
* In the central/peripheral neurons.
Serotonin is deaminated to
Serotonin is deaminated to 5-hydroxyindoleactic acid (5-HIAA)
which is the main urinary excretion product of serotonin
metabolism.
Gastrin Produced and stored mainly by
- the endocrine cells of the antral (pyloric)
mucosa (Stomach) - the proximal Duodenum (to a lesser
extent) - the cells of the Pancreatic islets.
Gastrin is transported via
transported via the blood through the liver
to the parietal cells of the stomach.
Gastrin functions
- Stimulates secretion of gastric acid,
- Stimulates secretion of gastric pepsinogens & intrinsic factor (IF),
- ## Stimulates secretion of pancreatic HCO3, enzymes, and hepatic bile,
- Increases gastric/intestinal motility,
- Mucosal growth
- Blood flow to the stomach.
Gastrin
Zollinger-Ellson syndrome
a condition in which there is increased production of the Gastrin.
* A small tumor (gastrinoma) in the pancreas or small intestine
produces the high levels of gastrin in the blood
Sex steroids
Synthesized from cholesterol in the ovaries, testes and adrenal
glands.
Once in the blood, they reversibly bind to sex-hormone binding
globulin (SHBG)
Roughly 1-2% of the sex hormones are in the free form.
Estrogens subtypes
- Estradiol (E2): predominant estrogen in non pregnant females
- Estrone (E1): metabolic product of estradiol
- Estriol (E3): only produced in significant amounts during pregnancy.
Estrogens are
steroid sex hormones derived from the ovarian follicle &
adrenal glands
Estrogens function
- Estrogens promote the secondary sexual characteristic changes in the
female
!hair distribution, fat distribution, breast development - Estrogens responsible for the follicular phase changes in the uterus.
Estrogen has what effect
Estrogen has local effect
that improve growth follicular cell
LH
FSH
Progesterone is involved in the
involved in the menstrual cycle, pregnancy, and
embryogenesis
Progesterone is what type of hormone.
Progesterone is a steroid hormone (C-21)
Progesterone is primarily a and is seen in very high levels in
Primarily a female sex hormone (corpus luteum)
❖Very high levels seen in pregnancy (due to placental synthesis) which
helps suppress pituitary hormones to prevent menstruation during
pregnancy
Progesterone functions
- Growth & Vascularization of uterine lining in preparation for
implantation of a fertilized ovum.
involved in the menstrual cycle, pregnancy, and
embryogenesis
Often measured with LH, FSH, Estrogen, and Prolactin to evaluate female infertility and
dysmenorrhea
Androgens are
Adrenal androgens are steroid sex hormones synthesized from
cholesterol by the adrenal cortex and testes.
aka Testosterone
Androgens
Testosterone is what androgen cell
the chief male androgen (testes) / (adrenal gland, 5%)
* production increases at puberty
Androgens function
Testosterone
- Maturation of secondary sexual characteristics
! muscles & bone development, deep voice, hair distribution - Male reproductive system
- Genital, prostate, and larynx including hypertrophy of larynx
- initiation of spermatogenesis.
HCG test
Serum or Urine β-hCG tests for presence of placenta
= pregnancy test
* HCG is a dipeptide hormone; the α peptide is the similar to LH,
TSH, FSH and other hormones, but the β peptide is unique;
∴ use immunoassay whose antibody is specific for the β peptide.
❖During the first trimester, serum hCG level doubles every 2 days
reflecting growth and healthy development of the placenta.
HCG test
what stays constant
Increase in Beta HCG in the absence of pregnancy indicates what
Tumors
