Morris Rockstein

AGING IN INSECTS

Publisher Summary This chapter discusses the different factors that result in the ageing process in an organism. Life span can be considered a genetically controlled trait as the inherited genotype determines the life span; however, it is also a biological characteristic that can be considerably modified by the environment. A finite life span can also be considered a mechanism to ensure species survival. Insects possess characteristics that make them especially useful as experimental animals in aging studies as they are made up of cells indistinguishable from those of higher animals including man, which in turn possess the full complement of biochemical systems involved in metabolism in general and in cellular functions in particular. Factors that affect the life span of an organism can be either intrinsic like genetic considerations—where gene action is involved in the ontogeny of all stages in the life cycle of insects—the sex of the organism, parental age, fecundity and egg laying, and time duration of the metamorphosis or extrinsic such as temperature range, ionizing radiation and nutrition, etc.

Age Changes in Adenine Nucleotides in Flight Muscle of Male House Fly

Under standard conditions of temperature, humidity, and (artificial) diet, loss in flight ability is paralleled by a decline of up to 66⅔ percent in activity of enzymes dephosphorylating organophosphorous compounds in the thoracic flight muscle. Concomitantly, the content of adenosine triphosphate in the flight muscle increases five times, while the content of adenosine monophosphate correspondingly diminishes.

Changes in phosphorus metabolism of the gastrocnemius muscle in aging white rats.

Summary Changes in the adenine nucleotide dephosphorylating system in the gastrocnemius muscle of aging male rats have been studied. The Mg-activated ATP-ase activity showed a pronounced fall from young to very old (senile) age in both the Sprague-Dawley and the CFN strains. However, in the former strain, old animals, typically exhibiting markedly greater losses in muscle mass and concomitant muscular dystrophy, also showed a greater decline in this enzyme on a unit muscle mass and even more so on an absolute body mass basis, than did the old CFN rats. In both strains, however, actomyosin (pH 9.0) ATP-ase as well as ATP content showed no significant changes from young to very old age. The role of the Mg-activated ATP-ase enzyme in energizing of skeletal muscle contraction and its possible significance in the physiology of senescence are discussed.

Oxidation of Palmitate-1-C14 by Red Blood Cells.∗

Summary Washed, red blood cells from normal, fed, adult rats were incubated in vitro in a modified Tyrode phosphate medium with palmitate-1-C14, the oxidation of which was demonstrated and measured by following the incorporation of radioactivity in the respiratory CO2. Rate of palmitate oxidation to CO2 has been shown to increase with number of red blood cells in the incubating vessels and with concentration of palmitate, and also depends on duration of the incubation. The data are discussed in relation to the present concepts of fat metabolism in vivo.