Salt and Water Homeostasis1. Human2. Toad Bladder3. Water Pore (red cell)

Module C10 June 2013Elyse Sadow, Pouya Jamshidi, Liza LichtenfeldKeais Pope, Samantha Harrington

Experiment

• Purpose: To determine the Kidney’s response to Water Load

1) 9 subjects. Two x 3hr Urine collections.2) Intervention: 5 Subjects Water-Loaded (4% TBW)3) Control: 4 subjects, 1 cup of water4) Measured Urine Volume, Osm, Chloride5) Calculated Excretion of Free Water, Salt, and Urea

44mL/kg=~4% tbw

Control before vs. after

Control before vs. after

InterventionBefore vs. After

InterventionBefore vs. after

Excretion equations

• Free Water Clearance per Hour=• [UVol-(UVol*UOsm/300)]/3hr

• UVolactual*UOsmactual=UVol300 *UOsm300

• Salt Excretion=(2*Cl)*UVol

• Urea=UOsm-(2*Cl)• Urea Excretion=Urea* UVol

•

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

1 2

Free water excretion

Salt excretion

0

20

40

60

80

100

120

140

160

180

1 2

Urea excretion

-100

-50

0

50

100

150

1 2

Experimental Set-Up

Time (min)

0 20 40 60 80 100 120 140 1600

0.2

0.4

0.6

0.8

1

1.2

Sample 1Sample 2Sample 3Sample 4Sample 5Sample 6Sample 7%

wei

ght c

hang

eADH

Experimental Data

Data Average

0 20 40 60 80 100 120 140 1600

0.2

0.4

0.6

0.8

1

Time (min)

% w

eigh

t cha

nge

ADH

ADH in Action

ATP

cAMP

AC AVP

BasolateralApical

V2 receptor

ADH in Action

ATP

cAMP

AC AVP

BasolateralApical

AQP-2

•Examining Water Pores in Red Blood Cells

Before mixing

After mixing

During mixing

H2O H2O

Schematic of Stopped- flow Fluorimeter

Isotonic vs Hypertonic

Inhibition of Water Transport

Glycerol Flow

Question?