Effect of glucose on the synthesis of testicular proteins separated by disc electrophoresis

Interaction of thiourea with rat lung protein

Administration of the pulmonary edemagenic agent [14C]Thiourea [( 14C]TU) to adult rats results in heterogeneous binding to lung protein. Indirect evidence suggests that TU may be binding to the amino acid cysteine, possibly via the SH moiety. The nature of the adduct is not known, but appears to involve one major and several minor species.

Inhibition by 5-thio-D-glucopyranose of protein biosynthesis in vitro in spermatids from rat testis

The effect of 5-thio-D-glucopyranose (thioglucose) upon protein biosynthesis in vitro was examine in testes from mature rats. Thioglucose in vitro is without demonstrable effect upon incorporation of L-[U-14C]phenylalanine into protein by whole testis but inhibits this incorporation by a purified fraction of immature spermatids (stages 1--8) prepared by centrifugal eluctriation; the inhibition is observed with or without glucose added in vitro and is concentration dependent in the range 1--50 mM. Similar inhibition is observed with three other 14C-labeled amino acids (leucine, lysine and glutamate). Mature spermatids (greater than stage 8) and other heterogenous fractions of testicular cells prepared by the same method also show inhibition by thioglucose of incorporation of phenylalanine into protein so that it is not possible to say that the effect is confined to spermatids although it is most pronounced in these cells. Inhibition of protein synthesis in vitro is also observed when thioglucose was administered in vivo (33 mg/kg body wt./day). This change occurs at the minimal dose observed by other workers to produce arrest of spermatogenesis and hence infertility.