Figure 1.

Molecular imaging by MALDI-FTICR-MSI of androgens analyzed intact and as Girard T derivatives in murine testes. Nonderivatized steroids could not be detected testes even following stimulation with human chorionic gonadotrophin (hCG). However, upon derivatization, testosterone and 5α-dihydrotestosterone (DHT) were detected. Optical images of a cryosection of murine testis (a, f) or rat prostate (m). Molecular image of (b) nonderivatized testosterone at m/z 289.2098 ± 0.005 Da in an hCG-stimulated mouse. Derivatized testosterone at m/z 402.3114 ± 0.0005 Da in testes from (c) control and (d) hCG stimulated mouse. (e) The relative abundance of testosterone (corrected for internal standard, corticosterone-d₈ (d₈-CORT)) was increased ∼2.5-fold following hCG stimulation. Molecular image of (g) nonderivatized DHT at m/z 291.2112 ± 0.0005 Da in an hCG stimulated mouse. Derivatized DHT at m/z 404.3264 ± 0.0005 Da in testes from (h) control and (i) hCG stimulated mouse. (j) The relative abundance of DHT (corrected for internal standard) was increased ∼1.8-fold following hCG stimulation. Derivatized testeosterone (n) and DHT (o) in rat prostate. Representative FTICR-MS spectrum of (k) testosterone and (l) DHT hydrazone in mouse testes and (p) both steroidal derivatives in rat prostate showing excellent agreement (mass accuracy ±5 ppm) with simulated theoretical isotopic distribution pattern (embedded). Data are mean ± SEM; n = 3 mice per group; cps = counts per second; scale bar = 2 mm. Signal intensity is depicted by color on the scale shown. ∗∗ = p < 0.01 compared by Student t-test.