Synthesis of hepatic lipase in liver and extrahepatic tissues

Journal Article · Sun Nov 01 04:00:00 EST 1987 · J. Lipid Res.; (United States)

OSTI ID:5303345

Doolittle, M H; Wong, H; Davis, R C; Schotz, M C

Immunoprecipitations of hepatic lipase from pulse-labeled rat liver have demonstrated that hepatic lipase is synthesized in two distinct molecular weight forms, HL-I (Mr = 51,000) and HL-II (Mr = 53,000). Both forms are immunologically related to purified hepatic lipase, but not to lipoprotein lipase. HL-I and HL-II are also kinetically related and represent different stages of intracellular processing. Glycosidase experiments suggest that HL-I is the high mannose microsomal form of the mature, sialylated HL-II enzyme. Hepatic lipase activity was detected in liver and adrenal gland but was absent in brain, heart, kidney, testes, small intestine, lung, and spleen. The adrenal and liver lipase activities were inhibited in a similar dose-dependent manner by hepatic lipase antiserum. Immunoblot analysis of partially purified adrenal lipase showed an immunoreactive band co-migrating with HL-II at 53,000 daltons which was absent in a control blot treated with preimmune serum. Adrenal lipase and authentic hepatic lipase yielded similar peptide maps, confirming the presence of the lipase in adrenal gland. However, incorporation of L-(/sup 35/S)methionine into immunoprecipitable hepatic lipase was not detected in this tissue. In addition, Northern blot analysis showed the presence of hepatic lipase mRNA in liver but not adrenal gland. The presence of hepatic lipase in adrenal gland in the absence of detectable synthesis or messenger suggests that hepatic lipase originates in liver and is transported to this extrahepatic site.

• Research Organization: Veterans Administration, Los Angeles, CA (USA)
• OSTI ID: 5303345
• Journal Information: J. Lipid Res.; (United States), Journal Name: J. Lipid Res.; (United States) Vol. 28:11; ISSN JLPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL GLANDS
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOSYNTHESIS
BODY
CARBOXYLESTERASES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
GENETIC MAPPING
GLANDS
HYDROLASES
IMMUNOASSAY
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPASE
LIPOTROPIC FACTORS
LIVER
MAMMALS
MAPPING
MESSENGER-RNA
METHIONINE
MOLECULAR WEIGHT
NUCLEI
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
RADIOISOTOPES
RATS
RNA
RODENTS
SULFUR 35
SULFUR ISOTOPES
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES