Experiment Station Record, Volume 94, January-June, 1946 Page: 44
xi, 975 p. ; 24 cm.View a full description of this book.
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44 EXPERIMENT STATION RECORD - [l. 94
Studies of fat and carbohydrate oxidation in mammalian spermatozoa, H. A.
LARDY and P. H. PHILLIPS. (Wis. Expt, Sta.). (Arch. Biochemn 6 (1945), No. 1,
pp. 53--61).--Experiments were undertaken to determine which intermediary metabolites
could be utilized by bull spermatozoa and whether the utilization of any of
these would be prevented by malonate. Comparative data were obtained on the
effect of 2,4-dinitrophenol on the utilization of the various metabolites. The hypothesis
that fats as well as carbohydrates are metabolized through the isocitric acid
cycle was supported by the following findings: "Glucose, pyruvate, i-lactate were
utilized by epididymal, and by malonate-treated, and 2,4-dinitrophenol-treated ejacuulated
spermatozoa. Succinate, fumarate, malate were not utilized by ejaculated bull
spermatozoa. These 4-carbon acids and oxalacetate were effective in reversing
malonate inhibition of motility and respiration. Oxalacetate improved motility
and respiration of normal bull spermatozoa and was the only 4-carbon dicarboxylic
acid effective in increasing respiration and supporting motility of dinitrophenoltreated
spermatozoa. Its efficacy may have been the result of decarboxylation to
pyruvate, which is utilized in both cases. Egg phospholipids increased respiration
and prolonged motility but were without effect on malonate or dinitrophenol inhibition
of endogenous respiration and motility. Acetate, acetoacetate, and /-hydroxybutyrate
did not stimulate respiration but prolonged maintenance of motility. They
support both respiration and motility of dinitrophenol-treated spermatozoa.
B-Hydroxybutyrate alone, among these fat intermediates, consistently increased
respiration and improved motility of malonate-treated spermatozoa. It seems probable
that the oxidation of /-hydroxybutyrate to acetoacetate supported motility in
this case. Acetoin, propionate, butyrate, a-glycerophosphate, a-hydroxyisobutyrate,
d-lactate were not utilized for the maintenance of motility. Spermatozoa and enzyme
preparations therefrom can synthesize citric acid from pyruvate or oxalacetate
under certain conditions. The enzyme aconitase is present in acetone-dried spermatozoa
and may be extracted into aqueous solution."
The metabolism of bovine epididymal spermatozoa, H. A. LARDY, R. G.
HANSEN, and P. H. PHILLIPS. (Wis. Expt. Sta.). (Arch. Biochem., 6 (1945),
No. 1, pp. 41-51).-Study of the metabolism of bovine epididymal spermatozoa
showed that the motility after removal from the epididymis was hastened by
aeration and could be prevented by the addition of cyanide to the medium. Freshly
removed epididymal spermatozoa incubated aerobically esterified inorganic phosphate
to produce an ester which appeared to be adenosine triphosphate. "Both the oxidation
of the endogenous lipid stores and the glycolysis of glucose are independently
coupled with this esterification." Rates of respiration and aerobic glycolysis of
epididymal sperm are much lower than those of ejaculated bull spermatozoa. Both
aerobic and anaerobic glycolysis are stimulated by bicarbonate. "Bovine epididymal
spermatozoa utilize pyruvate, /-lactate, a number of intermediates of Krebs' isocitric
acid cycle, acetate, acetoacetate,- f-hydroxybutyrate, and egg phospholipids under
aerobic conditions for the maintenance of motility. Epididymal bull spermatozoa
(like the ejaculated sperm) glycolyze glucose, fructose, and mannose at about the
same rate. The epididymal sperm differs from the ejaculated sperm in that it can
utilize maltose only at an extremely slow rate." There is an increased endogenous
rate of respiration of epididymal sperm resulting from storage and excised epididymides
in a refrigerator for 1 to 2 days. Epididymides from a local packing plant
were removed within an hour of slaughter and kept in a refrigerator. The spermatozoa
were removed in physiological saline. Experimental details were essentially
as described (E. S. R., 89, p. 530).
The factor in egg yolk affecting the resistance, storage potentialities, and
fertilizing capacity of mammalian spermatozoa, D. T. MAYER and J. F. LASLEY.
(Mo. Expt. Sta. et al.). (Jour. Anim. Sci., 4 (1945), No. 3, pp. 261-269, illus. 1).
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 94, January-June, 1946, book, 1947; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc5062/m1/55/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.