Variations in the level of transferrin and SGP-2 mRNAs in Sertoli cells of vitamin A-deficient rats.

Stage-specific levels and long-term effects of vitamin A deficiency on transferrin and sulfated glycoprotein-2 (SGP-2) mRNAs were analyzed in normal rats and in rats fed a vitamin A-deficient diet for 49 days (49 day VAD) and 77 days (77 day VAD). Histological sections of testes from these animals were hybridized in situ with single stranded 3H-labeled RNA probes complementary to the transferrin and SGP-2 (clusterin) mRNAs prepared from specific cDNAs subcloned in the SP65 vector. In all cases the probes were visualized and quantified by radioautography. Vitamin A deficiency (49 day VAD rats) differentially affected the levels of these mRNAs by increasing significantly the level of SGP-2 transcripts and decreasing the level of transferrin mRNA. However, in both cases the stage-specific pattern characteristic of the normal testes remained cyclic indicating that the specific interactions between germ cells and Sertoli cells may play an important role in modulating the cyclic activities of Sertoli cells. The data also indicated that dividing spermatocytes, secondary spermatocytes and steps 13-14 spermatids were associated with Sertoli cells expressing high levels of transferrin mRNA, while steps 7, 8 and particularly 19 spermatids were associated with Sertoli cells expressing high levels of SGP-2 mRNA. In contrast to the shorter term, a longer term of vitamin A deficiency (77 day VAD rats) produced a significant decrease in the levels of both transferrin and SGP-2 mRNAs.