Anti obesity screening models to perform the screening of new molecules/compounds to develop a new potential therapeutic drug for the treatment of central obesity.

1. Anti-obesity screening
models
National Institute of Pharmaceutical Education and Research
S.A.S Nagar, Mohali, Punjab(India)-160062
Presented by:
ISHFAQ AHMAD BHAT
18PCM2784
M.S(Pharm) 1st semester
Department of Pharmacology and Toxicology

2. Methods to induce experimental
obesity
1. Food induced obesity
• obesity can be induced in rats by offering a diet
containing corn oil and condensed milk
• Male SD rats housed in controlled conditions
• At the age of 6 months rats, divided into 2 groups,
ordinary Purina Rodent Chow is fed to G1, the G2 is fed
with Purina Rodent Chow, corn oil and condensed milk
• Body weight and food intakes measured, sacrificed after
3 months
• Adipose tissue cell size, lipid content, hormones, plasma
lipids are determined.

3. 2. Hypothalamic obesity
• Hyperphagia in rats induced after hypothalamic lesions
• Female SD rats, fed HFD for 5-9 days, fasted over night,
anesthetized with 35mg/kg pentobarbital sodium+1mg
atropine methyl nitrate
• Bilateral knife cuts or electrolytic lesions sterotaxically
positioned in the hypothalamus
• Histological verification of placement of knife ciuts is made
in brain fixed in 10% buffered formalin and embeded in
paraffin.
• serial sections of hypothalamus are examined histologically

4. 3. Goldthioglucose- induced obesity
• i.p or i.m injection of goldthioglucose induces
obesity in mice
• Related to destruction of hypothalamic and extra
thalamic areas of brain
• Swiss albino mice of either sex, fed with
commercial mouse chow
• At the age of 6 months, single i.p injection of 30-
40 mg/kg goldthioglucose
• Food intake and body weight determined for 3
months.

5. 4. Monosodium glutamate-induced
obesity
• Adiposity induced in mice by repeated s.c
injections of MSG
• Male charles river mice, treated immediately
after birth with daily s.c MSG for 5 days
• Animals weaned at 3 weeks age, housed
under controlled temp.
• Food consumption and body weight is
measured at the regular intervals

6. Assays of anti-obesity activity
1. Anorectic activity (food consumption in rats)
• Food intake and body weight measured in
acute and semichronic experiments in normal
or obese rats respectively
• Female zucker rats(250-350g), maintained
under controlled conditions
• Rats fed with special dishes along with test
compound or treated by i.p for 7 days
• Mazindol, 3mg/kg, a standard

7. 2. Metabolic activity (GDP-binding in
brown adipose tissue)
• Brown adipose tissue, a major site for non-shivering thermogenesis in
rodents
• Obese male fatty Zucker rats(age; 13 weks, weight; 450g), receive
multiple doses of test compound in the drinking or tap water for 21
days
• Food intake measured everyday, and bodyweight everyother day
• Rats sacrificed, brown adipose tissue minced, diluted with 250mM
sucrose and homogenized
• supernatant collected, centrifuged, BSA 0.2% added
• After centrifugation, pellet suspended in albumin free-sucrose buffer
• Binding of GDP to mitochondria is determined by incubating
mitochondria in basic medium containing 100mM sucrose, 20mM TES,
1mM EDTA, 1mM choline chloride, 2μM rotenone, and 10 μM 3H
rotenone.

8. 3. Uncoupling protein and GLUT4 in
brown adipose tissue
• Uncoupling proteins, family of inner mitochondrial
membrane transporters dissipate the proton
gradient
• UCP1 expressed exclusively in brown adipocytes
• Male fatty rats, 10 weeks age, given s.c injection of
test compound
• Sacrificed after 14 weeks treatment , brown and
white adipose tissue removed
• Northern and western blotting is performed , the
total RNA and GLUT4 proteins determined

9. 4. Resting metabolic rate
• RMR, influenced by various drugs both in normal
and obese animals
• Female yellow KK mice and female C57B1 mice,
age 12 weeks, housed under controlled
conditions, fed with commercial powdered chow
and tap water
• Test compound given i.m for 2 weeks
• Daily food intake and weight is measured
• RMR estimated by means of closed-circuit
metabolic system, consists of chamber, circulating
pumps, descicant and CO2absorbant canisters

10. 5. β3-adreceptor
• β3. receptor agonists produce weight loss in obese rodents due
to reduction in body fat
• Effect is observed without a decrease in food intake, thought to
be increased thermogenesis in brown fat, increased lipolysis,
leptin gene suppression and serum levels
• CHO cells expressing human β1, β2, and β3- receptors, transfected
with Camp response element-luciferase plasmids using
electroporation with 70ms, 150-V pulse
• Cells seeded and grown and treated with varying drug concs.
• Following drug exposure, cells are lysed and luciferase activity
measured using LucLite assay kit.
• Changes in light production measured by a topcount
luminometer