Biotin , B5 Competition/antagonizing Seems Not To Be Relevant?

[paymanz]

it is on peripheral blood mononuclear cells, so i dont know how much it applies to whole body biotin status.

in the previous studies either biotin concentra-
tions, pantothenic acid concentrations, or both were mod-
erately to substantially greater than those normally encoun-
tered in human plasma and thus may have led to masking of
a transporter of low V
max
resembling the PBMC transporter.
For example, in our studies of biotin transport across the
blood-brain barrier and the published studies using the
functionally expressed vitamin transporter from rat pla-
centa, biotin concentrations were 3 nmol/L and 35 nmol/L,
respectively 4,5 ; the biotin concentration in normal human
plasma is approximately 0.5 nmol/L. 17 In the same transport
studies, pantothenic acid concentrations were 250 m mol/L
and 100 m mol/L, respectively 4,5 ; the pantothenic acid con-
centration in normal human plasma is 0.1 m mol/L. 6 In the
study that addressed the inhibition of pantothenic acid
transport in human placental choriocarcinoma cells by
biotin, biotin concentrations were approximately 2 3 10
5
times higher than the physiologic serum concentrations. 1

Human peripheral blood mononuclear cells: ; Inhibition of biotin transport by reversible competition with pantothenic acid is quantitatively minor. - PubMed - NCBI


A transporter present in intestinal cells and in choriocarcinoma cells has been shown to transport both pantothenic acid and biotin at similar transporter affinities. However, the concentration of pantothenic acid in most foods and biological fluids is approximately 200 times the concentration of biotin; theoretically, pantothenic acid might substantially reduce biotin transport via competition. In the present study, we sought to determine whether pantothenic acid reduces biotin transport by the biotin transporter in peripheral blood mononuclear cells (PBMC). PBMC were isolated from human blood by gradient centrifugation. Incubations with [(3)H]biotin and pantothenic acid were conducted at physiologic concentrations. Intracellular [(3)H]biotin was quantified after washing by liquid scintillation counting. Pantothenic acid at 10 to 1,000 nmol/L reduced biotin (475 pmol/L) uptake by less than 12% (P < 0.05). Based on Lineweaver-Burk plots, the competition was reversible. Several structural analogs of pantothenic acid at 1,000 nmol/L reduced biotin transport by only 7 to 15% (P = 0.13). No pattern of molecular structure required for recognition by the transporter was apparent. Extracellular pantothenic acid did not affect biotin efflux from [(3)H]biotin-loaded PBMC (P > 0.05), suggesting that countertransport of extracellular pantothenic acid and intracellular biotin does not increase biotin efflux from PBMC. We conclude that the physiologic effects of pantothenic acid on the transport of biotin in PBMC are likely to be quantitatively minor.

We speculate that pantothenic acid
is unlikely to confound studies of biotin nutritional status
using biotin concentrations or carboxylase activities in
PBMC as indices. In addition, pantothenic acid in incuba-
tion medium is unlikely to confound transport studies of
biotin in PBMC.

 

[paymanz]

Effect of biotin and pantothenic acid on performance and concentrations of avidin-binding substances in blood and milk of lactating dairy cows. - PubMed - NCBI

We hypothesized that pantothenic acid reduces the absorption of biotin in lactating dairy cows. Therefore, the objective of this study was to evaluate the plausible interaction between biotin and pantothenic acid on production performance and concentration of avidin-binding substances (ABS), an indicator of biotin concentration, in blood and milk of lactating dairy cows. Eight primiparous and 16 multiparous Holstein cows were assigned to 1 of 4 diet sequences in a replicated 4×4 Latin square design with 18-d periods. Cows were housed in a freestall barn and fed once daily (0730 h) by means of a Calan gate system (American Calan Inc., Northwood, NH). Treatments consisted of a control diet that contained no B-vitamins, a biotin diet that contained 0.87 mg of biotin per kilogram of dry matter (DM), a pantothenic acid diet that contained 21 mg of pantothenic acid per kilogram of DM, and a biotin plus pantothenic acid diet that contained 0.87 mg of biotin and 21 mg of calcium pantothenic acid per kilogram of DM. Four different concentrates were prepared in a commercial feed mill. These concentrates were mixed with corn silage and grass hay and delivered ad libitum as a total mixed ration. Biotin supplementation did not affect DM intake, milk yield, or milk fat, protein, lactose, and milk-urea-nitrogen concentrations. Fat, protein, and lactose yields were not affected by treatments. The fat-to-protein ratio was <1 and similar among all treatments. Biotin supplementation did not increase the concentration of ABS in plasma. The supplementation of pantothenic acid did not affect the concentration of ABS in plasma when either supplemented alone or in combination with biotin. Biotin supplementation increased the concentration of ABS in milk relative to control. Contrary to our hypothesis, the supplementation of pantothenic acid did not decrease the concentration of ABS in milk relative to the control. When cows were supplemented with both biotin and pantothenic acid, the concentration of ABS in milk was similar to that of cows supplemented with biotin alone. In conclusion, pantothenic acid did not affect the concentrations of ABS in plasma and milk, suggesting that increasing dietary supply of pantothenic acid did not inhibit biotin absorption.

 

[paymanz]

another study

need to know at what dosage of b5 is those levels attainable...?

Functional and Molecular Aspects of Biotin Uptake via SMVT in Human Corneal Epithelial (HCEC) and Retinal Pigment Epithelial (D407) Cells

 

[Peater Piper]

If competition for transport is the primary concern, couldn't they just be supplemented at separate times?

 

[paymanz]

If competition for transport is the primary concern, couldn't they just be supplemented at separate times?

Idk ,maybe.in that case the half life and dosage becomes important to know how much time need to separate them?!

 

[Peater Piper]

Idk ,maybe.in that case the half life and dosage becomes important to know how much time need to separate them?!

Oh, wait, I was thinking only in terms of intestinal transport. Accounting for transport into PBMCs makes things a lot more difficult.

 

[paymanz]

Yes the other stuff is sodium dependant multivitamin transporter which makes it even more complex!!