[PHA6115 lec] Endocrine Drugs Flashcards
Composed of several hormone-releasing organs
Endocrine System
How does the endocrine system maintain body functions and homeostasis?
By releasing hormones which are used for several body functions (e.g., growth, reproduction, and defense)
Endocrine drugs work like __________?
Hormones (Natural, Semi-synthetic or Synthetic)
Classification of Endocrine Drugs based on Structure
- Peptide (majority)
- Steroidal (adrenal cortex / sex hormones) –> CCPT backbone
Classification of Endocrine Drugs based on Function
- Releasing hormones
- Stimulating hormones
- Thyroid and pancreatic, adrenal hormones
Complex disease characterized by uncontrolled glucose homeostasis associated with several minor and major complications
Diabetes
3 Cardinal Signs of Diabetes
- Polyuria
- Polyphagia
- Polydipsia
[Type of DM]
Insulin-dependent, juvenile onset, require insulin therapy for their lifetime
DM Type 1
[Type of DM]
Insulin-independent, adult onset (commonly), may or may not have insulin therapy
DM Type 2
[Type of DM]
Glucose intolerance during pregnancy
Gestational Diabetes
[Type of DM]
Results for non-usual causes or from other diseases present in the patient that may not concern insulin levels
Secondary DM
[Diabetes]
Therapy is directed at maintaining _________?
Euglycemic states (normal blood sugar)
It is a 51-amino acid protein with two chains linked by a disulfide bond
Insulin
Where is insulin produced?
Beta cells of pancreas
MOA of Insulin
Transports glucose into adipose and muscle cells via GLUT 4
SAR of Insulin
N- and C- terminals of the AA Chain A and B are essential for insulin receptor binding
Insulin is produced via __________ of proinsulin
Proteolytic modifications
Proinsulin is formed by removing what from preproinsulin?
24-amino acid
[Classification and Pharmacokinetics of Insulin Preparation]
Examples of Rapid-acting
Lispro, Aspart, Glulisine (LiAsGlu)
[Classification and Pharmacokinetics of Insulin Preparation]
Examples of Short-acting
Human Insulin - regular
[Classification and Pharmacokinetics of Insulin Preparation]
Examples of Intermediate-acting
Lente, NPH insuline (isophane)
> NPH means Neutral Protamine Hagedorn
[Classification and Pharmacokinetics of Insulin Preparation]
Examples of Long-acting
Ultralente, Glargine, Detemir (UltraDeGlar)
Agents that stimulate the release of insulin from the beta cells of the pancreas
Insulin secretagogues
2 Pharmacophores of Insulin Secretagogues
- Sulfonylurea
- Meglitinides
MOA of Sulfonylureas
Binds to SUR1 at K-channel and opens the voltage-gated Ca-Channel = Increased intracellular CA and exocytotic release of insulin
SAR of Sulfonylureas
1st generation
- small lipophilic at R1
- alkyl/cyclic substituent at R2
- high dose, long plasma half-life, short DOA, high chance for ADR
2nd generation
- large meglitinide group at R1
- high potency, low dose, rapid onset, short plasma half-life, long DOA
1st generation Sulfonylureas
Tolbutamide, Chlorpropramide, Acetohexamide (CAT-amide)
2nd generation Sulfonylureas
Glyburide or Glibenclamide, Glipizide, Glimepiride (“Gly or gli”)
MOA of Meglitinides
Similar to sulfonylureas; Repaglinide binds also to SUR1, SUR2A, and SUR2B = Extrapancreatic effects
SAR of Meglitinides
Meglitinide is a prototype structure - a benzoic acid derivative of the non-sulfonylurea moiety of Glibenclamide or Glyburide
Examples under Meglitinides
Repaglinide
- rapid onset, short DOA
- doesn’t cause prolonged hyperinsulinemia
- available in the market
Nateglinde
- rapid onset, longer DOA
Anti-diabetic agent that is considered the 1st line treatment with lifestyle change
Biguanides
T or F: Biguanides are highly distributed and excreted unchanged in urine
True
MOA of Biguanides
- decreases gluconeogenesis
- increases glycogenolysis and glycolysis
- increases insulin sensitivity
SAR of Biguanides
2-linked guanidine moiety (Bi + guanidie)
Insulin Sensitizers / PPAR Agonists, what does PPAR mean?
Peroxisome Proliferator Activated Receptor
MOA of Insulin Sensitizers or PPAR Agonists
- PPAR controls gene expression, increases glucose transporter expression = Increased insulin sensitivity of the body
- Slows down gluconeogenesis and lower systematic fatty acids
SAR of Insulin Sensitizers or PPAR Agonist
Thiazolidinedione pharmacophore
For agonist activity of the Thiazolidinedione pharmacophore, R must be __________?
Para- substituted phenyl ring attached via methylene bridge
Examples of Insulin Sensitizers or PPAR Agonists
Pioglitazone
- only available in the market
Troglitazone
- not used due to severe hepatotoxicity
Rosiglitazone
- limited availability due to increase cardiovascular effects
(TroPioRosi “-glitazone”)
Enzyme that is made of maltase, sucrase, isomerase, and glucomylase found in the small intestine
Alpha-glucosidase
MOA of A-Glucosidase Inhibitors
Inhibits a-glucosidase to inhibit carbohydrate breakdown = Preventing absorption of mono/disaccharides
SAR of A-Glucosidase Inhibitors
Mimic the natural substrates of a-glucosidase by having similar structures
This group aids in mimicking natural disaccharide substrate
Polyhydroxy groups
Examples of A-Glucosidase Inhibitors
Acarbose
- extremely low oral bioavailability
Voglibose
- poolry absorbed
Miglitol
- absorbed orally, not metabolized = excreted unchanged
30-31 amino acid peptide produced by prohormone convertase enzymes from proglucagon
GLP-1
MOA of GLP-1 Agonist
GLP-1 is released in response to food = Promotes insulin secretion from pancreas
SAR of GLP-1 Agonist
GLP-1 Agonist analogs have penultimate amino acid modification to resist metabolism by DPP-IV
[GLP-1 Agonist Agents’ Modification]
Penultimate Ala –> Gly
Exenatide
[GLP-1 Agonist Agents’ Modification]
Lys26 has a-glutamoyl-(N-a-hexadaconyl) and Lys34 is replaced by Arg34
Liraglutide
[GLP-1 Agonist Agents’ Modification]
Fusion of 2 modified GLP-1 to albumin
Albiglutide
[GLP-1 Agonist Agents’ Modification]
Fusion of 2 modified N-terminal GLP-1 analog to IgG4 Fc domain
Dulaglutide
Alternatives to GLP-1 Agonist Analogs
DPP-IV Inhibitors
MOA of DPP-IV Inhibitors
Binds to active site in DPP-IV
SAR of DPP-IV Inhibitors
3 pharmacophore structure:
a-aminoacylpyrrolidine, xanthine, pyrimidine-2,4-dione
Group that binds to the active serine site in DPP-IV
Cyano group
T or F: DPP-IV Inhibitors can be taken alone or with metformin or thiazolidinedione
True
Examples of DPP-IV Inhibitors
Saxagliptin and Vildagliptin (a-aminoacylpyrrolidine)
Sitagliptin
- piperazine fused pyrazole with a-aminoacyl moiety
Alogliptin
- pyrimidine-2,4-dione pharmacophore
Linagliptin
- xanthine pharmacophore
(VildaSaSiAloLi “-gliptin”)
37-amino acid hormone released with insulin
Amylin
MOA of Amylin Agonist
Suppress glucagon secretion and delay gastric emptying time = Modulation of appetite centers to maintain glucose plasma level
SAR of Amylin Agonist
Pramlintide
- more water soluble
- reduced aggregation
Aids in reabsorption of glucose from renal proximal tubules
SGLT2
MOA of SGLT2 Inhibitor
Inhibit SGLT2 = Decreased renal threshold for glucose = Increased urinary glucose excretion
SAR of SGLT2 Inhibitor
Phlorizin pharmacophore and a glucose moiety that bind to Thr156 and Lys 157 moiety of transporter
T or F: SGLT2 Inhibitor is recommended from patients with DM Type 1 and patients with renal impairment
False, not recommended
Examples of SGLT 2 Inhibitors
Phlorizin
- pharmacophore with glucose
Dapagliflozin, Empagliflozin, Canagliflozin
(Phlorizin + CanaDapaEmpa “-gliflozin”)
Only mammalian organ that can incorporate iodine into organic molecule
Thyroid gland
Source of throxine (T4) and triiodothyronine (T3)
Thyroid gland
Medications for disorders associated to thyroid gland
HRT and/or anti-thyroid drugs
Major regulatory step in Thyroid Glands
TSH release
Stimulates thyroid gland to create thyroid hormon
TSH
T3 or T4: Which one is the precursor?
T4 - thyroxine
T3 or T4: Which is the active form and is a negative feedback molecule for the anterior pituitary?
T3 - triiodothyronine
3 Types of Thyroid Replacement Hormones
- Hypothalamic - TRH
- Pituitary - TSH
- Organ - T4 and T3
Examples of Anti-thyroid Drugs
Thioamides, Anions, Radioactive I2, Propranolol
MOA of T4 and T3
T4 is transported into the cells and is converted into T3
T3 then enters the nucleus, interacts with DNA = Stimulation/Inhibition of gene transcription
SAR of T4 and T3
2 phenyl rings linked with X group
[SAR of T4 and T3]
X is
Oxygen
[SAR of T4 and T3]
R1 and R4’
R1 - alanine group
R4’ - OH group
[SAR of T4 and T3]
R3, R5, R3’
Iodine (T3)
[SAR of T4 and T3]
R5’
Iodine (T4)
[SAR of T4 and T3]
Potency between L and D-isomers
L-isomer is more potent than D-isomer
Slower-acting than iodides
Thioamides
MOA of Thioamides
Potent inhibitors of thyroperoxidase (TPO)
SAR of Thioamides
Thiouracil C2 keto/enol and unsubstituted N1 - essential for activity
Thiouracil C4 keto and C5/C6 alkyl substitution - increased activity
N1 methyl of MMI = Removes inhibition of peripheral deiodination
Examples of Thioamides
Propylthiouracil (PTU) and Methimazole (MMI)
MOA of Anions
Competitively blocks iodide transporter = Blocks iodine uptake
Examples of Anions
Pertechnetate, Perchlorate, Thiocyanate
MOA of Radioactive I2
Destroys thyroid gland cells = Lowers hormone levels
MOA of Propranolol
Inhibits deiodination of T4 to T3
Unsaturated steroid alcohol derived from terpenoid squalene
Sterols
What backbone does sterols possess?
CPPP
Where are sterols derived?
Natural sources such as;
Cholesterol (animals)
Phytosterol (plants)
Ergosterol (fungi)
What are the functions of sterols?
- Regulates cell membrane fluidity
- Precursor for bile acids
T or F: Sterols are also precursors for steroid hormones
True
Glucocorticoids, Mineralocorticoids, Sex hormones
General Steroid MOA
Bind to steroid receptors which are kept inactive by HSP
General Steroid MOA
Bind to steroid receptors which are kept inactive by HSP
Steroid-receptor enters nucleus several process occurs with Co-A and HRE of DNA
Steroid effects are seen in transcription of mRNA and translation of proteins
[Adrenal Glands and Different Zones]
Outermost
Glomerulosa - mineralocorticoids - Na and fluid reabsorption, K excretion
[Adrenal Glands and Different Zones]
Middle
Fasciculata - glucocorticoids - Intermediary metabolism, CV function, growth, immunity
[Adrenal Glands and Different Zones]
Innermost
Reticularis - gonadal hormones - primary and secondary sex characteristics, reproduction
Examples of Steroidal Drugs
Aldosterone (mineralcorticoid)
Cortisol (glucocorticoid)
Estradiol
- primary estrogen
- 2ndary female characteristics
Testosterone
- primary androgen
- 2ndary male characteristics
Progesterone
- primary progestin
- prepares uterus for pregnancy
T or F: Steroid structures will always contain CPPP backbone, like a modified cholesterol molecule
True
11-hydroxylated steroid hormone
Glucocorticoids
17-hydroxylated steroid hormone
Sex hormones
Only aldehyde-containing steroid hormone
Aldosterone
Only aromatic steroid hormone
Estrogen
SAR of Steroidal Drugs
C20 thiofluoromethyl = Increases GC receptor affinity
21-OH required for MC activity
21-Cl increases GC receptor affinity
SAR of Steroidal Drugs
C20 thiofluoromethyl = Increases GC receptor affinity
21-OH required for MC activity
21-Cl increases GC receptor affinity
X16 (a/b-methyl) substitution = Decreases MC activity but increases GC activity
6a/9a halogenation (F/Cl) = Enhances activity for both GC and MC
3-keto and delta-4,5 = Essential for activity of both GC and MC
11-b = Essential for GC activity
Delta-1,2 = Increases GC activity
Mainly used for their anti-inflammatory activity but can also be used for non-inflammatory uses
Glucocorticoids
MOA of Glucocorticoids
Promotes histone deacetylase activity = Reverse action of histone acetyltransferase = Inhibition of gene expression for inflammation
Uses of Glucocorticoids
Gout, arthritis, SLE, colitis, asthma, hypoglycemia, Addison’s disease
Availability of Glucocorticoids
Systemic and Topical corticosteroids
Examples of Glucocorticoids
Hydrocortisone
- aka cortisol
Prednisolone
[Non-inflammatory Effects of Glucocorticoids]
CNS
Profound behavioral changes when given in large doses
[Non-inflammatory Effects of Glucocorticoids]
Excretory
Normal renal excretion (MC effect)
[Non-inflammatory Effects of Glucocorticoids]
Gastric
Stimulation of gastric acid secretion, which can lead to
development of peptic ulcer
[Non-inflammatory Effects of Glucocorticoids]
Bone
Antagonism of the effect of vitamin D on calcium absorption
[Non-inflammatory Effects of Glucocorticoids]
Blood
Increase of platelets and RBC
[Non-inflammatory Effects of Glucocorticoids]
Respiratory
Development of fetal lung
Uses of Mineralocorticoids
Addison’s disease, diagnosis of Conn’s syndrome
Examples of Mineralocorticoids
Aldosterone
- regulation of salt and water in the body
- not commercially available
Fludrocortisone
- used to raise cortisol and for detecting Conn’s syndrome through the fludrocortisone suppression test
AKA male sex hormones produced by the Leydig cells of testis, adrenal, and ovary
Androgens
Major androgen in males that is synthesized from progesterone or dehydroepiandrosterone (DHEA)
Testosterone
Testosterone is activated by ___________ into dihydrotestosterone (DHT) that occurs usually in the prostate organ of the body
5a-reductase
Effects of Androgen
Normal development of male during infancy to puberty
Development of facial, pubic, and auxiliary hair; darkening of skin
Anabolic action
Increased muscle size and strength
Increased RBC production
Helps maintain normal bone density
Effects of Androgen
Normal development of male during infancy to puberty
Development of facial, pubic, and auxiliary hair; darkening of skin
Anabolic action
Increased muscle size and strength
Increased RBC production
Helps maintain normal bone density
[Anti-androgen agents]
Androgen-receptor blockers
Spironolactone
[Anti-androgen agents]
Examples of Spironolactone
Flutamide, Nilutamide, Trifluorophenyl derivatives
[Anti-androgen agents]
Agents for BPH or Prostate Cancer
Finasteride and Dutasteride
- steroid amide as 5a-reductase inhibitor
Quinazolines
- alpha-1 blockers
Abiraterone
- steroidal agent that blocks enzymes responsible for the synthesis of androgens
Serenoa repens
- Saw palmetto
C-18 steroid with aromatic ring
Estrogen
Estrogen exists in 3 forms
Estradiol (most potent)
Estrone
Estriol
C21 with 3-keto-4-ene, C20 keto)
Progestins
Progestins naturally occur as _______
Progesterone (most potent)
Uses of Estrogen and Progestins
Hypogonadism in young females, contraception, and HRT
Aside from sex characteristics, Estrogen contributes to ________
Bone integrity - prevents bone resorption
MOA of Estrogens
Binds to ER(a/b) = Dimerization - migrates to the cell nucleus and binds to specific estrogen-response elements (ERE) = DNA transcription
ADRs of Estrogen
Increased risk for breast and endometrial cancer, breast tenderness
Nausea, increased risk for migraine
HTN
Thromboembolic events
Progestins added to estrogen during HRT to reduce unwanted effects
Modified Progestins
SAR of Modified Progestins
Androstane or pregnane steroid nuclei = Essential for progestic activity
Etc
MOA of Anti-Progestins
Competes with progesterone at receptor sites
SAR of Anti-Progestins
Contain C11-phenyl group that aids in competitive receptor blockade
Examples of Anti-Progestins
Ulipristal
- for emergency contraception
Mifepristone
- for abortion
[Anti-Estrogen for Cancer Therapy]
Used for estrogen-related cancer
Aromatase Inhibitor
Ex. Anastrozole, Exemestane
[Anti-Estrogen for Cancer Therapy]
Used for breast CA, but may cause endometrial CA
Selective Estrogen Receptor Modulators (SERMs)
Ex. Ospemifene - dyspareunia
Raloxifene - osteoporosis
Clomifine - infertility
3 Primary Hormones involved in managing Ca levels in the Body
Calcitonin (CT), Parathyroid hormone (PTH), and Vitamin D
Promotes urinary secretion of Ca and prevents intestinal absorption during hyperglycemia
Calcitonin
Promotes inhibits renal secretion of Ca and promotes bone resorption during hyperglycemia
PTH
MOA of 2nd Generation SERMs
Agonist activity on estrogen receptors in osteoblast and osteoclast but in the breast and uterus
SAR of 2nd Generation SERMs
Triarlyethylene derivatives of Tamoxifen
Phenol/Phenoxy ring system = Essential to mimic A-ring of estrogen for receptor binding
Propeller orientation of 3 rings = Essential for receptor binding and activity
Examples of 2nd Generation SERMs
Lasofoxifene, Ospemifene, Bazedoxifene, Toremifene
MOA of Bisphophonates
Binds to the hydroxyapatite of the bone = Prevents osteoclast activity = Reduces osteoclast proliferation and life span
SAR of Bisphophonates
Analogs of pyrophsphates
R1-OH = Maximizes affinity for hydroxyapatite = Improved antiresorptive activity
R2 substitution can vary
Amino alkyl with 3-atom chain with the N atom in a heterocyclic ring = Optimal activity
Examples of Bisphophonates
Etidronate, Risedronate, Alendronate, Pamidronate
(RiEtiAlePami “-dronate”)
[Other agents]
Decrease bone resorption by osteoclast
Calcitonin
[Other agents]
PTH analog, increases number of osteoblast
Teriparatide
[Other agents]
Calcimimetic, increase Ca sensitivty = Lower PTH secretion = Lower serum Ca levels
Cinacalcet
[Other agents]
Increases mineralization of hydroxyapatite = Stronger bones/teeth
Sodium fluoride
[Other agents]
Increase bone formation and decrease bone resorption
Strontium ranelate