Biomedical subjects

D R Brison

Publications and source records attributed to D R Brison.

21 records · Page 2Linked to original sources

PubMed1993

Glucose, pyruvate, and lactate concentrations in the blastocoel cavity of rat and mouse embryos.

The concentrations of glucose, pyruvate, and lactate have been measured in the blastocoel fluid of single rat and mouse blastocysts, using the technique of micropuncture combined with an ultramicrofluorescence assay. When cultured in the presence of 5.55 mM glucose, 11.5-12.5 mM L-lactate and 0.25-0.33 mM pyruvate, concentrations in the blastocoel fluid of mouse and rat were 2.30 and 2.75 mM glucose, 14.6 and 19.6 mM L-lactate, and 0.13 and 0.50 mM pyruvate, respectively. When cultured in the presence of 1.0 mM glucose and 1.0 mM L-lactate, concentrations in the blastocoel fluid were 0.50 and 0.59 mM glucose and 2.22 and 3.70 mM L-lactate, respectively. These results suggest that (1) the blastocyst is capable of maintaining considerable concentration gradients of substrates across the trophectoderm, (2) the microenvironment of the blastocoel is adequately supplied with energy substrates for the development of the inner cell mass, and (3) the inner cell mass is capable of developing in both high and low glucose and lactate concentrations.

Animals↗

PubMed1993

Role of chloride transport in the development of the rat blastocyst.

Preimplantation mammalian development culminates in the generation of a fluid-filled cavity, the blastocoel, which requires the vectorial transport of ions across the trophectoderm, followed by the movement of water. Experiments were carried out to establish the role of Cl- transport in blastocoel formation in the rat. These included investigations of the effect of Cl- substitution and the Cl- transport inhibitors 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, furosemide, and anthracene-9-carboxylic acid, on the development of morulae into blastocysts in culture, and on the rate at which blastocoel fluid is accumulated. In addition, a novel technique was developed in which the Cl(-)-sensitive fluorescent dye 6-methoxy-N-(3-sulfopropyl) quinolium (SPQ) was loaded into the blastocoel cavity, in order to characterize the pathways of transtrophectodermal Cl- transport. We established that 1) blastocoel formation in the rat requires the external presence of Cl- ions; 2) transport across the trophectoderm appears to be via a transcellular pathway, since rates of blastocyst development, fluid accumulation, and SPQ-monitored Cl- efflux are all reduced in the presence of Cl- transport inhibitors; and 3) Cl- transport occurs via Cl-/HCO3- exchange.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1991

Energy metabolism in late preimplantation rat embryos.

The consumption of pyruvate and glucose, and the production of lactate, by single preimplantation embryos, was measured using a noninvasive technique. Embryos were cultured in 300-500-nl microdrops, for 8-12 h at a time, from Day 4 to Day 6 after mating, when they developed from the 8-cell stage to expanded blastocyst. Pyruvate was the predominant substrate at the 8-cell/morula stage; glucose uptake exceeded that of pyruvate after the onset of blastocoel formation. Lactate production increased in parallel with glucose consumption. For most stages, approximately 100% of the glucose uptake was accountable for by lactate production and in some cases an additional source of lactate must be postulated. Culture in vitro had little effect on lactate production, although a lower level of metabolism was observed compared with fresh blastocysts. Rat embryos were capable of developing to blastocysts in the absence of glucose, when lactate production was greatly reduced.

Animals↗