FIG. 8.

LH induces testosterone production but not EGF-like ligand expression in primary mouse Leydig cells. Primary mouse Leydig cells were stimulated with or without LH for 30 min then medium was collected to measure testosterone levels by RIA (A) and cells were collected to determine mRNA levels of amphiregulin, epiregulin, betacellulin, and heparin bound EGF by real-time PCR (B). Leydig cells were also stimulated with LH in the presence of doxycycline (75 μM, C) or MMP2/9 V inhibitor 9 (20 μM, D) and testosterone levels in the medium were measured as before. Data are represented as fold induction over unstimulated control (CON) in A and B, and fold induction over MOCK or inhibitor alone (DOX, MMP2/9) in C and D. Ct values were in the 30s (relatively low) for amphiregulin, epiregulin, betacellulin, and heparin-bound EGF before and after 30-min stimulation with LH. Each bar represents the average ± SEM. Identical results were seen in two experiments. *P < 0.05 relative to unstimulated control using Student two-tailed t-test. **P < 0.05 relative to LH stimulation using Student two-tailed t-test.