1. The effects of insulin, glucagon and a supply of exogenous amino acids on protein degradation have been studied in isolated perfused livers from growing chickens by measuring the rate of net valine release in the presence of cycloheximide. 2. Insulin inhibited protein degradation as did a supply of exogenous amino acids. 3. Addition of glucagon increased uric acid release from the livers but had no significant effect on protein degradation. 4. When the effects of the hormones and amino acid mixture are compared with published data for the rat it is evident that the action of glucagon differs in the two species.

Amino Acids↗

PubMedDate not supplied

Effect of administration of a novel recombinant bovine interferon on length of oestrous cycle in cattle.

In ruminants, extensive reproductive loss occurs during the process of maternal recognition of pregnancy and it has been suggested that trophoblast interferons may be potential therapeutic agents. This paper reports results from a trial using eight first lactation Holstein-Friesian heifers to test the efficacy of a novel recombinant bovine interferon produced in bacteria in extending the life of the corpus luteum. Oestrus was synchronised in these animals and 0.1 mg of this non-glycosylated interferon was infused into the uterus twice daily for 13 days starting approximately 12 days after oestrus. This treatment resulted in an extension of the lifespan of the corpus luteum by 5.5 days (P=0.028) compared with untreated controls. In these animals the interovulatory period was extended by 6.4 days (P=0.009). Administration of this protein did not have any adverse effects either on body temperature or on daily milk yields. The results indicate that this novel interferon may have potential therapeutic application for reducing embryo mortality.

Animals↗

PubMedDate not supplied

Effect of a novel recombinant bovine interferon and trophoblast secretory products on protein metabolism by endometrial explants from cattle and sheep.

The effect of a novel recombinant bovine interferon on the rate of protein synthesis, as measured by the rate of leucine incorporation, in endometrial explants from cows and ewes was investigated and compared with the effect of trophoblast secretory proteins and of a recombinant bovine interferon-alpha1. Exposure of cultured bovine endometrial tissue to the novel recombinant bovine interferon mimicked the effect of pregnancy in reducing the rate of protein synthesis in both caruncular and intercaruncular endometrium. This effect was similar to that seen with naturally produced trophoblast secretory proteins and it was more pronounced than that seen when endometrial tissue was treated with a related recombinant bovine interferon-alpha1. Ovine endometrial cultures were unaffected by exposure to this novel recombinant bovine interferon. This novel recombinant interferon exhibited potent antiviral properties (an activity of 1.6 x 10(10) international reference units/mg protein) and may prove to be a valuable reagent in studying the maternal recognition of pregnancy in the cow and reducing embryo mortality.

Animals↗