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Ash content of bones from a hibernator
ANNUAL
MEETING
During entry into hiberation, the average rate of cooling of Tb was O.Ol’iC/min (range = O.OlO0.026), and it usually took more than 24 hr before the Tb reached its stabilized minimum level. The decrease of Tb was not passive; intermittent leveling or slight increase of Tb was observed frequently during the entry period. The minimum Tb during hibernation was 175°C in September and gradually declined to 2.l”C in March. The length of individual hibernation bouts extended progressively from 4 days in September to 24 days in February, and decreased abruptly to 3 days just before the terminal arousal in March. The rewarming of Tb from hibernating to normothermic level requires 1.5 to 6 hr depending on the individual and the initial Tb from which arousal commenced. The average rate of arousal was O.l’i”C/min (range = 0.12-0.22). Results obtained from laboratory studies using t,hhc same technique will be discussed. (Supported by NRC Grant A-6455.) 7.
Lipid und Fatty Acid Composition of Tissues of Hibernating Ground Squirrels, Citellus Lateralis. E. T. PENGELLEY, AND R. C. ALOIA* (Department of Biology, University of California, Riverside, CA 92502) introduced by S. J. Asmundson.
Hibernating ground squirrels, Citellus lateralis were sacrificed between the third and seventh da? of an established hibernating cycle in a 5”C-environment, and their hearts and livers were removed and frozen in liquid nitrogen. Lipid extraction, Sephadex-column and thin-layer chromatographic separation of lipid classes and phosphorus analysis of the hearts and livers of t.hesc heterothermic mammals indicates that t,he percent,agc of each lipid rlass appears similar to strictly homothermic mammals and to the composit,ion in active (37°C) ground squirrels. These results were expected. Gas-liquid chromatographic analysis of fatty acid-methyl esters of t,hc entire lipid ext,racts and of individual phospholipid classes is in progress and the results will be presented. The object, of these comparisons is based on the expectation Ihnt an increase in percentage of unsaturation will occur in the tissues of heterothermic mammals in hiberation as compared to active (37°C) heterot,hermic and homothermic (37°C) mammals. Potential theories on the functioning of hibernator hearts at low t,emperatures will be discussed under the headings, percentage of unsaturation of fatty acids. or cryoprotectire agents such as circulating steroid hormone or a prostaglandin which may allow greater membrane fluidity at low temperatures. (Support.ed by NSF Grant GB8605, USPHS -HL13532-02, Riverside Country Heart Association and University of California.)
ABSTRACTS 8. Ash Content of Bones from a Hibernator. M. L. ZIMNY,* G. PECK,* ASD C. WOODARD* (Department of Anatomy, Louisiana State University Medical Center, New Orleans, LA 70112) introduced by R. Webster. Femurs were removed from 10 control and 10 hibernating thirteen-lined ground squirrels, Citellus tridecemlineatus. All hibernating animals had hibernated 2-3 weeks. The bones were soaked in two changes of 1: 1 acetone methanol for 24 hr and dried to constant weight in an oven. Weighings were made on a Cahn Electrobalance. The bones were then ashed in a muffle oven at 600°C for 24 hr. Ash aliquots were analyzed for Na, K, Ca and Mg by means of atomic absorption spectrometry and for PC using the Fiske-SubbaRow reaction and photospectrometry. Control values were as follows: Ca 35.3 mg%; PI 38.7 mg%; Mg 0.30 my%. Na 40 mcquiv/liter; and K 4.5 mequiv/liter. Hibernating values were as follows: ca 40.7 mg%; Pi 39.9 mg%; Mg 0.34 mg%; Na 36 mequiv/lit,er; and K 4.0 mequiv/liter. The only significant change, when the hibernating ground squirrels as compared wit,11 controls, is the 15.6% increase in hone calcium. Smaller samplings of humeri and pelves support these findings. It may be t,hat. the peripheral ischemia of hibernation is promoting calcium deposition in the long bones. These deposits may then act. as a metabolic pool for homeostatic mechanisms during hiberation. For purposes of correlation light, microscopic and tlransmission and scanning electron microscopic studies arc in progress. (Supported by NIH Grant No. Am-2027.) 9.
Variations i,L Hibernating Behavior of th,e Cit,ellus lateralis ire Kesponse Ground Squirrel lo Daylength and Intensity of Light. E. T.* PEXGELLEY, AND S. J. ASMUNDSON (Department of Biology, University of California, Riverside, Cd 92502).
Laboratory born ground squirrels. Citellus were maintained from birth under constant conditions of 23°C and a 12L12D schedule. Animals when weaned were divided into five groups and placed in individual cages. Group 1 and 3 were bilaterally enucleated and groups 2, 4 and 5 were left normal. On September 1 all groups were transferred to cold boxes wit,h a const,ant temperature of 3°C. Light schedules were as follows: Group 1 (enucleatedj-DD, Group 2LL (500 lx), Group 3 (enucleatrdj-LL (500 lx), Group 4-LL (20 lx) and Group 5--12I.-12D (200 lx). Records of activity and hibernation were taken daily and weight recorded bimonthly. To date one complete annual cycle from the onset of Intern/is,
MEETING
During entry into hiberation, the average rate of cooling of Tb was O.Ol’iC/min (range = O.OlO0.026), and it usually took more than 24 hr before the Tb reached its stabilized minimum level. The decrease of Tb was not passive; intermittent leveling or slight increase of Tb was observed frequently during the entry period. The minimum Tb during hibernation was 175°C in September and gradually declined to 2.l”C in March. The length of individual hibernation bouts extended progressively from 4 days in September to 24 days in February, and decreased abruptly to 3 days just before the terminal arousal in March. The rewarming of Tb from hibernating to normothermic level requires 1.5 to 6 hr depending on the individual and the initial Tb from which arousal commenced. The average rate of arousal was O.l’i”C/min (range = 0.12-0.22). Results obtained from laboratory studies using t,hhc same technique will be discussed. (Supported by NRC Grant A-6455.) 7.
Lipid und Fatty Acid Composition of Tissues of Hibernating Ground Squirrels, Citellus Lateralis. E. T. PENGELLEY, AND R. C. ALOIA* (Department of Biology, University of California, Riverside, CA 92502) introduced by S. J. Asmundson.
Hibernating ground squirrels, Citellus lateralis were sacrificed between the third and seventh da? of an established hibernating cycle in a 5”C-environment, and their hearts and livers were removed and frozen in liquid nitrogen. Lipid extraction, Sephadex-column and thin-layer chromatographic separation of lipid classes and phosphorus analysis of the hearts and livers of t.hesc heterothermic mammals indicates that t,he percent,agc of each lipid rlass appears similar to strictly homothermic mammals and to the composit,ion in active (37°C) ground squirrels. These results were expected. Gas-liquid chromatographic analysis of fatty acid-methyl esters of t,hc entire lipid ext,racts and of individual phospholipid classes is in progress and the results will be presented. The object, of these comparisons is based on the expectation Ihnt an increase in percentage of unsaturation will occur in the tissues of heterothermic mammals in hiberation as compared to active (37°C) heterot,hermic and homothermic (37°C) mammals. Potential theories on the functioning of hibernator hearts at low t,emperatures will be discussed under the headings, percentage of unsaturation of fatty acids. or cryoprotectire agents such as circulating steroid hormone or a prostaglandin which may allow greater membrane fluidity at low temperatures. (Support.ed by NSF Grant GB8605, USPHS -HL13532-02, Riverside Country Heart Association and University of California.)
ABSTRACTS 8. Ash Content of Bones from a Hibernator. M. L. ZIMNY,* G. PECK,* ASD C. WOODARD* (Department of Anatomy, Louisiana State University Medical Center, New Orleans, LA 70112) introduced by R. Webster. Femurs were removed from 10 control and 10 hibernating thirteen-lined ground squirrels, Citellus tridecemlineatus. All hibernating animals had hibernated 2-3 weeks. The bones were soaked in two changes of 1: 1 acetone methanol for 24 hr and dried to constant weight in an oven. Weighings were made on a Cahn Electrobalance. The bones were then ashed in a muffle oven at 600°C for 24 hr. Ash aliquots were analyzed for Na, K, Ca and Mg by means of atomic absorption spectrometry and for PC using the Fiske-SubbaRow reaction and photospectrometry. Control values were as follows: Ca 35.3 mg%; PI 38.7 mg%; Mg 0.30 my%. Na 40 mcquiv/liter; and K 4.5 mequiv/liter. Hibernating values were as follows: ca 40.7 mg%; Pi 39.9 mg%; Mg 0.34 mg%; Na 36 mequiv/lit,er; and K 4.0 mequiv/liter. The only significant change, when the hibernating ground squirrels as compared wit,11 controls, is the 15.6% increase in hone calcium. Smaller samplings of humeri and pelves support these findings. It may be t,hat. the peripheral ischemia of hibernation is promoting calcium deposition in the long bones. These deposits may then act. as a metabolic pool for homeostatic mechanisms during hiberation. For purposes of correlation light, microscopic and tlransmission and scanning electron microscopic studies arc in progress. (Supported by NIH Grant No. Am-2027.) 9.
Variations i,L Hibernating Behavior of th,e Cit,ellus lateralis ire Kesponse Ground Squirrel lo Daylength and Intensity of Light. E. T.* PEXGELLEY, AND S. J. ASMUNDSON (Department of Biology, University of California, Riverside, Cd 92502).
Laboratory born ground squirrels. Citellus were maintained from birth under constant conditions of 23°C and a 12L12D schedule. Animals when weaned were divided into five groups and placed in individual cages. Group 1 and 3 were bilaterally enucleated and groups 2, 4 and 5 were left normal. On September 1 all groups were transferred to cold boxes wit,h a const,ant temperature of 3°C. Light schedules were as follows: Group 1 (enucleatedj-DD, Group 2LL (500 lx), Group 3 (enucleatrdj-LL (500 lx), Group 4-LL (20 lx) and Group 5--12I.-12D (200 lx). Records of activity and hibernation were taken daily and weight recorded bimonthly. To date one complete annual cycle from the onset of Intern/is,