Abstract
The characteristics of phosphate transport across the human intestinal basolateral membrane were determined using an enriched preparation in which uphill Na+-dependent d-glucose transport could not be demonstrated but adenosine triphosphate-dependent calcium transport was present. The human basolateral membrane vesicles were oriented as follows: 64% inside-out vesicles and 36% rightside-out vesicles or sheets, or both. Phosphate transport showed a 3.4-fold transient "overshoot" phenomena in the presence of an inwardly directed sodium gradient. Computerized Michaelis-Menten kinetics for the net active transport component indicated a Vmax of 65 ± 5 pmol/mg protein per 8 s and a Km of 93 ± 15 μM. The transport process was electroneutral. Gramicidin D and transstimulation studies confirmed the presence of a Na+-phosphate carrier at the basolateral membrane. Adenosine triphosphate enhanced phosphate uptake, indicating an adenosine triphosphate-dependent phosphate transport process. These studies are the first to determine the presence of a phosphate carrier in human intestinal basolateral membrane.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 106-113 |
| Number of pages | 8 |
| Journal | Gastroenterology |
| Volume | 93 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 1987 |
| Externally published | Yes |
ASJC Scopus subject areas
- Hepatology
- Gastroenterology