Rats were subjected to cerebral compression ischaemia for 15 min and were subsequently recirculated with blood for periods up to 3 h. In viuo incorporation of intravenously administered ~-[l-'~CJvaline into total brain proteins was found to be severely inhibited (about 20% of controls) after 45 min of recirculation. After 3 h, protein synthesis had increased, the specific radioactivity of proteins then being about 40% of controls. The post-ischaemic inhibition of protein synthesis was accompanied by a breakdown in polyribosomes and a concomitant increase in ribosomal subunits. In vitro incorporation of ~-['~C]phenylalanine by a postmitochondrial supernatant system derived from animals subjected to 15 min ischaemia and 15 min recirculation was also severely reduced and showed, in contrast to control animals, no response to the addition of a specific inhibitor of polypeptide chain initiation (Poly (1)). Together with the in uioo accumulation of ribosomal subunits this indicates a block in peptide chain initiation during the early stages of recirculation.Polyribosomes from animals subjected to 15 min ischaemia without recirculation showed a normal rate of in oitro protein synthesis which was inhibited by Poly(1) to a similar extent as polyribosomes from control animals. These results suggest that the post-ischaemic inhibition in chain initiation develops during the early stages of recirculation rather than during the ischaemic period itself.
ABSTRACT. To examine the ovarian response to Arcanobacterium pyogenes (A. pyogenes) in uterus, bacterial solution was infused into the uteri of cows, and the follicle and corpus luteum (CL) development were monitored with a real-time ultrasound instrument. In addition, the plasma concentrations of progesterone (P 4 ) and 13, 14-dihydro-15-keto-PGF 2α (PGFM) were determined. A 10 ml bacterial solution that contained A. pyogenes (8 to 15 × 10 8 CFU/ml) was infused into the uterus of eight cows transcervically three days after natural ovulation. As a control, sterile physiological saline was infused into 4 other cows. The dominant follicle developed normally in 8 cows after bacteria inoculation. In 4 of these 8 cows, the developing CL regressed, and the first wave dominant follicles, which normally become atretic, ovulated after the inoculation. In the remaining 4 cows, the CL did not regress. The PGFM concentration increased transiently in all 8 cows after the infusion. The mean PGFM concentration of the cows with a regressed CL was significantly lower (P<0.01) than that of the cows whose CLs did not regress. In the control cows, there was no regression of developing CLs, no ovulation of first wave dominant follicles and no transient increase in PGFM after the infusion of sterile physiological saline. These results show that infusion of A. pyogenes into the uterus did not affect folliculogenesis and might have induced PGF 2α production from the uterus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.