Table 3. Tumour porphyrin synthesis from ALA and ALA derivatives after systemic administration to mice and ALA content.

	nmol ALA or ALA derivatives/g tissue at 10 min	nmol ALA or ALA derivatives/g tissue at 3 h	nmol porphyrins/g tissue at 3 h
Control	12.5±0.9	12.5±0.9	0.36±0.05
ALA	170.2±8.4	15.11±5.1	15.9±1.12
He-ALA	56.3±10.3	12.9±1.5	3.11±0.42
Undecanoyl-ALA	28.2±3.1	11.2±3.4	2.64±0.23
THP-ALA	37.0±5.2	17.8±2.8	8.83±0.95

In all, 3.3 mg ALA, 5 mg He-ALA, 6.3 mg undecanoyl-ALA and 5.2 mg THP-ALA were administrated i.p. to mice. After 10 min, the ALA content was determined and after 3 h ALA and porphyrins were quantified in tumour. PBG levels at 10 min and 3 h were undetectable.