Glycoprotein biosynthesis by testes of 40-day-old rats subjected to protein malnutrition.

The testes of 40-day-old rats subjected to protein malnutrition show a marked delay in maturation of the seminiferous epithelium, as well as greater mannose incorporation into glycoprotein than observed in normal animals of the same age. Testes were incubated for 1 h with [2-3H]mannose and germ cells were then separated by the Staput method. Mannose incorporation occurred in the same cell fraction, i.e. the spermatocytes, both in normally fed and protein-undernourished animals. These data were confirmed by incubating the cells previously isolated on the gradient with [2-3H]mannose. Comparison of these data with results obtained in previous studies on 20-day-old animals in which mannose incorporation was lower in undernourished rats suggests that the differences observed in the present study between the experimental groups are due to alterations in the germ cells.