Specific effect of arachidonic acid on 17β‐hydroxysteroid dehydrogenase in rat Leydig cells

Abstract

It is well known that arachidonic acid (AA) acts as an intratesticular factor regulating luteinizing hormone-mediated testicular steroidogenesis. The present studies were conducted to determine the effect of AA on steroidogenic enzymes in rat Leydig cells. Exogenously added AA significantly inhibited 22(R)-hydroxy-cholesterol-stimulated testosterone production, which is a clear indication that AA is acting at some point after cholesterol transport to the inner mitochondrial membrane. AA failed to block the conversion of 22(R)-hydroxycholesterol to pregnenolone, indicating that the cytochrome P-450 side-chain cleavage enzyme complex is not the site of inhibition. The present results demonstrate that only 17beta-hydroxysteroid dehydrogenase seems to be involved in the AA action, since nearly 60% inhibition of testosterone production was found when the cells were incubated with androstenedione. Furthermore, no effect of AA was found when androstenediol was used as substrate in the testosterone synthesis, which indicates that 3beta-hydroxysteroid dehydrogenase is not affected by AA. The conversion of AA to its metabolites is not required for its action on 17beta-hydroxysteroid dehydrogenase and the activation of protein kinase C is not involved in the inhibitory effect.

Circadian clock gene BMAL1 controls testosterone production by regulating steroidogenesis‐related gene transcription in goat Leydig cells

“…These cultured goat LCs possessed a typical spindle‐shaped morphology (Figure S3), and similar to the morphology of sheep LCs (Deng et al, 2018). In addition, we also showed that hCG or 22R‐OH‐cholesterol stimulated testosterone production in goat LCs in a dose‐dependent manner (Figure 2a,b), which is in line with observations from mouse LCs and rat LCs (Marinero et al, 1998; Wang et al, 2019). Moreover, hCG (5 IU/ml) stimulated intracellular cAMP production in goat LCs (Figure 2c).…”

“…Twenty‐four hours later, the culture medium was removed and replaced with serum‐free M199 medium containing 0.1% BSA (Sigma‐Aldrich) and 1× AA. To measure the steroidogenic activity of LCs, we used 22R‐OH‐cholesterol (Sigma‐Aldrich) because it is more water‐soluble (Marinero et al, 1998). For the 22R‐OH‐cholesterol treatment experiment, goat LCs were incubated in the presence of different concentrations (0, 0.1, 0.5, 1, 3, 5, 10, 20, and 30 μM) of 22R‐OH‐cholesterol, and each concentration was used in triplicate (Marinero et al, 1998).…”

“…To measure the steroidogenic activity of LCs, we used 22R‐OH‐cholesterol (Sigma‐Aldrich) because it is more water‐soluble (Marinero et al, 1998). For the 22R‐OH‐cholesterol treatment experiment, goat LCs were incubated in the presence of different concentrations (0, 0.1, 0.5, 1, 3, 5, 10, 20, and 30 μM) of 22R‐OH‐cholesterol, and each concentration was used in triplicate (Marinero et al, 1998). After 2 h, the culture medium was collected, centrifuged at 800 g for 5 min, and the supernatant was collected to analyze its testosterone content.…”

Aspirin inhibits androgen response to chorionic gonadotropin in humans

“…In this regard, it has been reported that another cyclooxygenase inhibitor, indomethacin, is able to inhibit 3␤-hydroxysteroid dehydrogenase and 17␤-hydroxysteroid dehydrogenase activities in rat testis (22). On the other hand, more recently, it has been shown that AA by itself exerts a specific inhibitory effect on 17␤-hydroxysteroid dehydrogenase in rat Leydig cells (13). However, with regard to human testis, these possibilities seem to be unlikely because the present study indicates that aspirin treatment does not affect steroidogenesis in conditions of nonexposure to exogenous hCG.…”

Raf‐ERK1/2 signalling pathways mediate steroid hormone synthesis in bovine ovarian granulosa cells

“…It is widely accepted that steroidogenesis is controlled by multiple signalling pathways. For example, cAMP/PKA pathways regulate steroid hormone biosynthesis by steady state levels of STAR protein (Manna & Stocco, ), and arachidonic acid (AA)‐mediated signal inhibits testosterone synthesis via blocking 17‐HSD protein activity (Marinero et al, ), whereas for females, the levels of P4, E2 and T are changed along with oestrus and gestation. Thus, the mechanisms of steroidogenesis are more complicated than previously thought in ovary.…”