NephronKetoacids.TXT

Created : 2013-02-23
Revised : 2013-02-23
Author : Tom Coleman

Wildenhoff infused 3-hydroxybutyrate (3-HB) into normal
subjects. Fractional reabsorption and fractional excretion
were constant and showed no signs of saturation. Fraction
meaning fraction of the filtered load.

87% of filtered 3-HB was reabsorbed and 17% was excreted up
to 130 (uMol/Min)/M^2). GFR ~ 100 mL/Min)/M^2. So maximum
plasma [3-HB] was 1.3 mMol/L in this study.

Sapir and Owen looked at starvation for up to 24 days.

Day     GFR [3-HB] Load  Reab Urine  Reab-F
------- --- ------ ----- ---- -----  ------
Control 101  0.28    28    29   ~0     100
3       105  2.39   251   154   97      61
10      107  5.15   551   419  132      76
17       98  5.14   504   399  105      79
24       91  6.10   555   436  119      78

Sapir et.al. studied 15-24 days of total starvation. They
then added glucose, but it is their control data that we
want.

[AcAc] (mMol/L)     1.27
[3-HB] (mMol/L)     5.00
KA Urine (mMol/Day)  122
KA Urine (mMol/Day)  118 - /100 mL GFR
NH3 Urine (mMol/Day) 148 - /100 mL GFR
AA Reab (uMol/Min)    79
3-HB Reab (uMol/Min) 279

KA mG/dL * 0.098 = mMol/L

Martin and Wick's data indicates that reabsorption is
starting to saturate at ~ 5 mMol/L, but this is built on
one data point in one subject.



References ==================================================

Martin, H.E. and A.N. Wick. Quantitative relationships
between blood and urine ketone levels in diabetic ketosis.
JCI 22(2):235-241, 1943.

Sapir, D.G. et.al. The effect of carbohydrates on ammonium
and ketoacid excretion during starvation. JCI 51:2093-2102,
1972.

Sapir, D.G. and O.E.Owen. Renal conservation of ketone bodies
during starvation. Metabolism 24:23-33, 1975.

Wildenhoff, K.E. Tubular reabsorption and uriny excretion of
acetoacetate and 3-hydroxybutyrate in normal subjects and
juvenile diabetics. Acta Med. Scand. 201:63-67, 1977.

End