Microbial protein and peptide metabolism in rumen fluid from faunated and ciliate-free sheep.

1. Protease and deaminase activities and the metabolism of peptides were measured in rumen fluid from ciliate-free sheep and from sheep with a limited population of small entodinia. The same measurements were repeated following inoculation of the latter group with a more typical mixed ciliate population.

Protein degradation by ruminal microorganisms from sheep fed dietary supplements of urea, casein, or albumin.

Ruminal fluid from sheep fed hay plus concentrate diets containing 1.8% urea, 6% casein, or 6% egg albumin had proteolytic activities of 4.12, 3.

A faster radioimmunoassay of progesterone in plasma, with use of polyethylene glycol as precipitant.

We report a reliable radioimmunoassay for plasma progesterone in which polyethylene glycol ("Carbowax 6000") is used to separate antibody-bound and free hormone. Initially, progesterone is concentrated by putting the sample through a column of LH-20 Sephadex. Procedural losses in each sample are not monitored.

A rapid specific radioimmunoassay for unconjugated estriol in plasma.

A rapid, non-chromatographic radioimmunossaay for unconjugated estriol in pregnancy plasma has been developed which utilizes a commonly available antiestrogen antisera. Estradiol-17beta and estrone demonstrate 135% relative cross-reactivity with our antiserum, as compared with 100% for estriol. Specificity is achieved by purification of estriol with solvent partitioning using benzene: petroleum ether (1:1).

Nonchromatographic radioimmunoassay of unconjugated estriol in plasma, with polyethylene glycol as precipitant.

We describe a rapid, reliable radioimmunoassay for unconjugated estriol in plasma. Polyethylene glycol (Carbowax 6000) is used to separate antibody-bound and free steroid. The assay is sensitive (25 pg for standards), precise, and accurate.