Characterisation of penicillin G uptake in human small intestinal brush border membrane vesicles.
BACKGROUND
Many beta lactams are well absorbed by the small intestine, although the reasons for this are poorly understood.


OBJECTIVE
To characterise the uptake of penicillin G into human small intestinal brush border membrane vesicles (BBMV) and to compare the uptake characteristics to those of rabbit BBMV.


RESULTS
Uptake of penicillin G was studied in human BBMV. Penicillin G was actively transported into the lumen of BBMV via an H+ dependent, Na+ independent uptake system. The carrier mediated process was saturable and adhered to Michaelis-Menten kinetics (Vmax 52 nmol penicillin G per mg protein per 30 seconds, Km 13.9 mM). These results are similar to those previously reported in rabbit BBMV.


CONCLUSIONS
It is suggested that penicillin G can be used as a model molecule for peptide and beta lactam transport studies as it is cheap and readily available in isotopically labelled form. Furthermore, rabbit BBMV may be used as an acceptable substitute for human BBMV for the study of penicillin transport.
Poschet
J F
JF
Digestive Disease Research Centre, St Bartholomew's and the Royal London School of Medicine and Dentistry, Turner Street, London E1 2AD, UK.
Hammond
S M
SM
Fairclough
P D
PD
D000818:Animals; D001693:Biological Transport, Active; D046508:Culture Techniques; D006801:Humans; D007408:Intestinal Absorption; D007583:Jejunum / Q000378:metabolism* / Q000648:ultrastructure; D008871:Microvilli / Q000378:metabolism; D009994:Osmolar Concentration; D010400:Penicillin G / Q000493:pharmacokinetics*; D010406:Penicillins / Q000493:pharmacokinetics*; D011817:Rabbits
D010406:Penicillins; D010400:Penicillin G