Glutamyl transferase system

Tadalafil pharmacokinetics in patients with ED showed linear relation with respect to dose and duration of treatment, and a one-compartment model adequately described the data. The absorption rate was rapid (1.86 h ), and the t)q)ical population estimates of the apparent oral clearance (CL/F) and apparent volume of distribution were 1.6 L/h and 63.8 L, respectively. Disposition parameters showed a moderate degree of interindividual variability (39-45%). The value of CL/F decreased slightly with increasing serum y-glutamyl transferase (GGT) concentration, the only statistically significant covariate detected. Systemic exposure to tadalafil was not influenced by age, weight, smoking status, alcohol consumption, liver enz nne status, ED severity, cardiovascular condition, or diabetes mellitus. 

E519 Franzini, C., Cattozzo, G. and Morelli, A. (1989). Gamma-glutamyl transferase assay Results from two closed analytical systems equalized by mathematical manipulation. Biochim. Clin. 13, Suppl. 1/8, 310, Abstr. B 160. 

Proximal tubule cells in culture should have retained functional attributes such as (1) polar architecture and junctional assembly of epithelia and correct membrane distribution of enzymes and transport systems (2) vectorial transport of solutes and water, manifested by the formation of domes when cultured on solid supports [81] and the generation of transepithelial electrophysiological properties [82, 83] due to the expression of proximal tubule specific claudins 2- and 10 [84, 85] (3) cellular uptake of xenobiotics from either the apical or basolateral side, as observed in vivo and (4) expression of nephron segment-specific characteristics, i.e., distinct expression of differentiation markers, metabolic and transport properties, and hormone responsiveness. Such markers include the expression of the brush border enzymes alkaline phosphatase, leucine aminopeptidase, and y-glutamyl transferase [4, 86], In addition, proximal tubule cells should possess Na+,K+-ATPase activities, Na+-dependent glucose, and p-aminohippurate transport. Proximal tubule cells increase cAMP levels in response to parathyroid... 

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