title: Gluconeogenesis-linked glycogen metabolism is important in the achievement of in vitro capacitation of dog spermatozoa in a medium without glucose.
abstract: In vitro capacitation of dog spermatozoa in a medium without sugars and with lactate as the metabolic substrate (l-CCM) was accompanied by a progressive increase of intracellular glycogen during the first 2 h of incubation, which was followed by a subsequent decrease of glycogen levels after up to 4 h of incubation. Lactate from the medium is the source for the observed glycogen synthesis, as the presence of [(14)C]glycogen after the addition to l-CCM with [(14)C]lactate was demonstrated. The existence of functional gluconeogenesis in dog sperm was also sustained by the presence of key enzymes of this metabolic pathway, such as fructose 1,6-bisphophatase and aldolase B. On the other hand, glycogen metabolism from gluconeogenic sources was important in the maintenance of a correct in vitro fertilization after incubation in the l-CCM. This was demonstrated after the addition of phenylacetic acid (PAA) to l-CCM. In the presence of PAA, in vitro capacitation of dog spermatozoa suffered alterations, which translated into changes in capacitation functional markers, like the increase in the percentage of altered acrosomes, a distinct motion pattern, decrease or even disappearance of capacitation-induced tyrosine phosphorylation, and increased heterogeneity of the chlorotetracycline pattern in capacitated cells. Thus, this is the first report indicating the existence of a functional glyconeogenesis in mammalian spermatozoa. Moreover, gluconeogenesis-linked glycogen metabolism seems to be of importance in the maintenance of a correct in vitro capacitation in dog sperm in the absence of hexoses in the medium.
authors.affiliation: Unit of Animal Reproduction, Department of Animal Medicine and Surgery, School of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Albarracín
authors.forename: J M
authors.initials: JM
authors.lastname: Fernández-Novell
authors.forename: J
authors.initials: J
authors.lastname: Ballester
authors.forename: M C
authors.initials: MC
authors.lastname: Rauch
authors.forename: A
authors.initials: A
authors.lastname: Quintero-Moreno
authors.forename: A
authors.initials: A
authors.lastname: Peña
authors.forename: T
authors.initials: T
authors.lastname: Mogas
authors.forename: T
authors.initials: T
authors.lastname: Rigau
authors.forename: A
authors.initials: A
authors.lastname: Yañez
authors.forename: J J
authors.initials: JJ
authors.lastname: Guinovart
authors.forename: J C
authors.initials: JC
authors.lastname: Slebe
authors.forename: I I
authors.initials: II
authors.lastname: Concha
authors.forename: J E
authors.initials: JE
authors.lastname: Rodríguez-Gil
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D003470:Culture Media / Q000737:chemistry*; D004285:Dogs / Q000378:metabolism / Q000502:physiology*; D005943:Gluconeogenesis / Q000502:physiology*; D005947:Glucose; D006003:Glycogen / Q000378:metabolism*; D019344:Lactic Acid / Q000008:administration & dosage; D008297:Male; D010648:Phenylacetates / Q000494:pharmacology; D013075:Sperm Capacitation / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*
chemical_list: D003470:Culture Media; D010648:Phenylacetates; D019344:Lactic Acid; D006003:Glycogen; C025136:phenylacetic acid; D005947:Glucose