The effects of gossypol on nuclear protein in rat testes. I. Reduction in the content of basic proteins in the spermiogenic cells.

ABSTRACT

In rat testes, after 45 days of gossypol treatment, the number of round spermatids (RS) reduced from 9.8 x 10(6) to 6.2 x 10(6) per testis. The number of elongating spermatids (ES) reduced from 6.4 x 10(6) to 3.1 x 10(6) per testis. Total nuclear basic proteins (TNBP, i.e., somatic type of histones H1, H2A,B, H3, and H4, plus testis-specific proteins TP1,2,3, and sperm-specific S1 proteins) were extracted from RS and ES. Gossypol has no detectable effect on the concentration of TNBP in RS. However, significant effect was found in ES, where TNBP was reduced from 8.7 micrograms to 6.8 micrograms/10(6) cells. A two-stage polyacrylamide gel has been used to separate the TNBP and the individual proteins were quantified by a Beckman Model DU-7 computer-monitored spectrophotometer. In the RS cells, the content of the TNBP was not sensitive to gossypol. However, in the ES cells, the content of histones H1, H2A, and H2B were reduced by gossypol treatment (with an inhibition of 50%, 58%, and 31%, respectively). The inhibition on H3, TP1, TP3 and S1 was insignificant by gossypol.