Rat brain glial cells in primary culture and subculture contain the delta, epsilon and zeta subspecies of protein kinase C as well as the conventional subspecies

We raised polyclonal antibodies against the C-terminal peptides of protein kinase C (PkC) subspecies alpha, beta 1, beta 2, gamma, delta, epsilon, and zeta and checked their specificity against brain extracts using Western immunoblot analysis. With equal amounts of protein applied to gels PkC subspecies beta 1, delta, epsilon and zeta were detected in primary cultures of mixed glial cells: bands for the alpha and beta 2 subspecies were less prominent. PkC gamma was not detected in primary glial cultures. The epsilon and zeta subspecies of PkC were detected in subcultures of type 1 astrocytes with weaker bands for the alpha, beta 1 and beta 2 subspecies. Blots of O-2A-lineage glia contained PkCs delta and zeta as prominent bands: the alpha, beta 1 and epsilon subspecies were also present. All PkC subspecies including PkC gamma were detected in C6 glioma cells.

Non-invasive measurement of pyruvate and glucose uptake and lactate production by single human preimplantation embryos

The consumption of pyruvate and glucose and the production of lactate by 40 single human preimplantation embryos has been measured using a non-invasive technique. Twelve of the embryos showed abnormal fertilization. Of the 28 normally fertilized embryos, nine (32%) developed to the blastocyst stage in culture while the remainder degenerated or arrested during cleavage. In the normal embryos, pyruvate uptake exceeded that of glucose in the early developmental stages (days 2-5 post-insemination) before glucose became the predominant substrate in the blastocyst (day 6). Considerable quantities of lactate were formed throughout development, rising from a value of 43.6 pmol/embryo/h on day 2.5 to 95.4 pmol/embryo/h on day 5.5. The values of pyruvate and glucose uptake and lactate production of those embryos which arrested were below those which developed normally. On the basis that one mole of glucose can give rise to two moles of lactate, only 50% of the lactate produced could be accounted for in terms of glucose uptake from the medium. This figure rose to 90% in the blastocyst. The remaining lactate must be derived from endogenous sources, most probably glycogen. It is proposed that the high production of lactate by human preimplantation embryos in vitro is an adaptation to the conditions of culture.

The mechanism and control of rabbit oviduct fluid formation

The formation of rabbit oviduct fluid was monitored continuously by using an in situ vascular perfusion technique. Oviduct fluid was secreted linearly for at least 3 h at a mean rate of 20.8 +/- 1.5 microliter/h in estrous does. The rate more than doubled on Day 1 following mating, was similar to the value at estrus on Day 2, and dropped to 8.3 microliter on Day 3. Dibutyryl cyclic adenosine 3',5'-monophosphate (cAMP, 1 mM) added to the vascular medium abolished fluid secretion. The same response was obtained, after a lag period, following the addition of cholera toxin (1 mM), forskolin (1 mM), theophylline (1 mM), phorbol dibutyrate (40 microM), A23187 (2 micrograms/ml), 4-acetamido-4'-isothiocyonatostilbene-2,2'-disulphonic acid (SITS, 1 mM), and bumetanide (10 microM) to the vascular medium. N-ethylmaleimide (1 mM), which inhibits adenylate cyclase, stimulated oviduct fluid formation. The transmural potential difference (p.d.) across the oviduct was 5.46 +/- 1.01 mV. This was increased after cAMP addition to 8.7 +/- 1.22 mV. The p.d. in oviducts taken 3 days post-ovulation was 7.6 +/- 1.75 mV, and was increased by cAMP to 12.7 +/- 0.53 mV. Exposure to cholera toxin and forskolin almost doubled the cAMP content of the oviduct. The undirectional flux of chloride ions from the vascular compartment into the lumen was reduced by about 75% after the addition of cAMP, SITS, and bumetanide. A tentative model to account for the formation and regulation of rabbit oviduct fluid in terms of ion fluxes and cAMP and calcium ion concentrations is presented.