Modifications in the Testis Steroidogenic Pathways in Rats Fed with Cottonseed Flour

Abstract

Suppression of the testicular T production by effect of the CSF has been previously reported. Changes in the testicular content of intermediates and precursors of T biosynthesis were determined in rats fed during 28 days with diets containing 25, 35 and 50% of CSF and compared with a defated cottonseed flour diet group and a control Purina-chow diet group. Also described were modifications during a six wk post CSF diet period. The results showed a diminution in pregnenolone and progesterone testicular content to a third and a half of the control values (21.5 and 19.3 pg/mg of protein respectively). Other compounds in the .A5 pathway, 17 hidroxypregnenolone and dehydroepiandrosterone were undetectable since the 35% CSF diet, the 17 hidroxyprogesterone diminished to undetectable values only with the maximal (50%) CSF content diet. During the post CSF diet period all the steroids showed a tendency toward the control values. The 25% CSF content diet group reached the initial contents; other groups presented different recovery degrees. The most affected was the 50% diet group with a direct effect of the CSF on the testicular androgen steroidogenesis affecting both the .A4 and the .As pathways.Key Words: Gossypol, testis, steroidogenic pathways INTRODUCTIONThe gossypol effects on the morphology and motility of spermatozoa are well documented [4, 9, 113, however, its effects on the testicular endocrine function is controversial, since initial reports as well as other papers have found no changes in the plasmatic hormones [ 1, 113. Lin et al. showed a significant decrease of plasmatic testosterone (T) levels with a possible blockade of testicular steroidogenesis [ 101.The antifertility effect, similar to that of gossypol, was demonstrated in rats fed with whole cottonseed flour (CSF) supplemented diets [12]. A decrease was found in the testicular content of three active androgens as well as a decrease in T serum levels [8].To correlate those results with a blockade in the androgen steroidogenic pathways the testicular content of As precursors pregnenolone (Preg), 17 hidroxypregnenolone (170HPreg), dehydroepiandrosterone (DHEA); A4 intermediates-progesterone (Prog), 17 hidroxyprogesterone (170HPrbg), and the active androgens-androstenedione (A), testosterone (T) and 5 a dihydrotestosterone (DHT) were measured by specific radioimmunoassays (RIAs) in rats fed with CSF additioned diets. MATERIALS AND METHODSThe CSF diets were prepared and evaluated as reported [ 121, the experimental procedure was as follows: Diets containing 100% defated CSF or 25, 35 and 50% whole CSF and a control Purina chow diet were used to feed 5 groups with 10 adult male Sprague-Dawley rats each during 4 wk. At the end of the exposure period 4 animals from each group were sacrificed by decapitation; the remaining animals were fed a purina chow diet during 3 to 6 wks to allow their recovery prior to their sacrifice. The testes were separated. decapsulated, and homogenized in buffered saline solution to a final volume of 5 mi, aliquots of homogenates...