Abstracts - Deutsche Zoologische Gesellschaft

198 Physiology PostersP PH.24 - ENNorepinephrine-induced non shivering thermogenesis (NST) in obesity resistant (SWR/J) and obesity prone (AKR/J) miceNadine Rink, Gerhard Heldmaier, Carola W. MeyerDepartment of Animal Physiology, Philipps Universität MarburgDifferent strains of inbred mice are known to differ in their response to high fat feeding. An exampleis the susceptibility of AKR/J mice to DIO (diet induced obesity) whereas mice SWR/J are resistant.In mammals, UCP1 (uncoupling protein 1) mediated NST not only plays a role for generating heat inthe cold, but is also recruited for wasting excess energy, a phenomenon known as diet-induced thermogenesis(DIT). We hypothesized that resistance to DIO in SWR/J mice is associated with higherNST capacity in vivo. In our study we fed SWR/J and AKR/J mice (35 days old) with either chow(C, 3.3% crude fat) or high fat diet (HF, 20.1% crude fat) for one week. We compared body mass,and determined changes in basal metabolic rate (BMR), and NST maximum following injection ofNorepinephrine (NE; 1.5 mg/kg s.c.). When chow fed, neither BMR nor NST maximum was differentbetween strains, despite a lower body mass in SWR/J mice. As expected, HF feeding causedan increase in body mass of AKR/J mice, but not in SWR/J mice. Following HF feeding, BMR andNST maximum increased in AKRJ mice, corresponding to the increase in body mass. In contrast,BMR and NST maximum were not different between SWR/J mice receiving either C or HF diet.These results suggest that obesity resistance in SWR/J mice is not due to a specific increase in NSTcapacity with HF feeding, but results from a greater overall metabolic turnover.P PH.25 - ENAdipokinetic hormone gene sequence from Gryllus bimaculatus (Ensifera: Gryllidae)Gustavo R. Makert 1 , Matthias W. Lorenz 1,21Department of Animal Ecology I, University of Bayreuth, 2 Department of Animal Physiology,University of BayreuthThe adipokinetic hormones (AKHs) belong to one of the best characterized families of insect neuropeptides.The AKHs play a decisive role in the mobilization of energy from fat body during flight,egg production, moulting or stress situations (fight, extreme temperatures, hunger). In addition tothe identification of AKH peptides, knowledge of the AKH genes is of central importance. For thisreason we screened a cDNA library from G. bimaculatus to isolate and identify its AKH sequence.After cloning and sequencing the cDNA it was possible to propose the complete organization of G.bimaculatus AKH. The sequence of the G. bimaculatus AKH cDNA begins with an 89-nucleotide5´-untranslated region, a 20 amino acid signal peptide, the 8 amino acid AKH peptide, followed bythe amidation signal, a dibasic cleavage site and a 36 amino acid AKH-precursor related peptide.The cDNA ends with a 116-nucleotide 3´-untranslated sequence followed by a polyadenylation tailof undetermined length. The cricket AKH precursor displays a high sequence similarity with thoseof the cockroaches Periplaneta americana and Blaberus discoidalis. Age-dependent expression ofthe AKH gene in the corpora cardiaca (CC) of adult female crickets, together with data on theage-dependent AKH peptide content within the CC is presented. Their physiological significance isdiscussed in relation to flight performance and reproduction during early adult life. Supported by theDFG (Lo 697/4-3 and 4-4).