LYSOSOMAL HYDROLASES AND NEUTRAL LIPASE OF CULTURED FIBROBLASTS AND ADIPOSE TISSUES OF MONKEYS AND CHILDREN

Abstract

Monolayer cultures of normal skin fibroblasts (NSF) from 4 children, lipid storage fibroblasts (LSF) from 2 children with lipid storage diseases - a Wolman's disease and a cholesterol ester storage disease -, a subline of “lipid-storing” Swiss mouse fibroblasts (3T3-L1), human adipose tissues (HAT) obtained at surgery from 5 normal children and monkey adipose tissues (MAT) from 13 adult monkeys (Macaca mulatta), were incubated at 37°C for 2 hr. in 5% CO₂ atmosphere with and without 5×10⁻⁴M isoproterenol (Iso) and 5×10⁻³M theophylline (Theo.) Neutral lipase (NL) at pH 7.0, lysosomal acid lipase (LAL), hexosaminidase (Hex) and B-galactosidase (Gal) each at pH 4.0, were assayed on the aqueous fractions of cell and tissue homogenates using 4-methylumbelliferyl compounds as substrates. Basal specific activity (n mole/min/mg/prot.) of NL in HAT (3.14±0.67) was highest, being 3 to S times higher than the values for LSF, 3T3-L1 or MAT. Basal activity of AL was 28.41±7.06 in NSF and 17.33±7.02 in 3T3-L1 but less than 10% of these values in LSF, HAT and MAT. Basal activities of Hex. and Gal. were higher in NSF, LSF and 3T3-L1 than in HAT and MAT. Stimulation with Iso. plus Theo. produced no effects on the activity of any of the enzymes studies with the exception of NL activity in HAT which increased by 50%.

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