Meeting Abstract

P1.86  Monday, Jan. 4  Rainbow Trout Possess Two Hormone Sensitive Lipase-Encoding mRNAs that are Differentially Expressed and Differentially Regulated by Fasting KITTILSON, J.D.; REINDL, K.M.; SHERIDAN, M.A.*; North Dakota State Univ., Fargo mark.sheridan@ndsu.edu

Teleost fish store lipids among several tissues primarily as triacylglycerol (TG). Upon metabolic demand, stored TGs are hydrolyzed by hormone-sensitive lipase (HSL). In this study, two distinct cDNAs encoding HSL were isolated, cloned and sequenced from adipose tissue of rainbow trout. The two partial cDNAs, designated LIPE 1 and LIPE 2, were 715 bp and 818 bp in length, respectively, and share 85% nucleotide identity. Quantitative real-time PCR revealed that the LIPE 1 and LIPE 2 were differentially expressed, both in terms of distribution among tissues as well as in terms of abundance within selected tissues of juvenile trout. LIPE 1 and LIPE 2 mRNAs were detected in brain, spleen, pancreas, kidney, gill, intestine, heart, white muscle, but were most abundant in red muscle, liver, and adipose tissue. LIPE 1 was more abundant than LIPE 2 in adipose tissue, whereas LIPE 2 was more abundant than LIPE 1 in liver. Short term fasting (2 week) increased LIPE 1 and LIPE 2 expression in adipose tissue, whereas prolonged fasting (4-6 weeks) increased LIPE 1 and LIPE 2 mRNAs in red muscle and LIPE 2 expression in liver. Refeeding reduced LIPE expression to levels seen in continuously fed fish. These findings indicate that the pattern of LIPE expression is consistent with the diverse lipid storage pattern of fish and suggest that distinct mechanisms serve to regulate differential expression of the two LIPEs is tissues and during a progressive fast. (Supported by NSF IOS 0920116)