Fig. 3.

ALLO and 7α-OH PREG are abundantly synthesized and released from the quail chick pineal gland. (A) Neurosteroids synthesized from PREG in the pineal gland of male quail chicks. The pineal glands were incubated with the substrate [³H]PREG, and the extracts were subjected to HPLC. The arrows indicate elution positions of the substrate PREG (open arrow) and its metabolites (solid arrows). (B) Comparison of the amount of neurosteroids synthesized from PREG in the pineal gland of male quail chicks by HPLC (n = 8). **P < 0.01 vs. 5α-DHP, AD, or T; ^†††P < 0.001 vs. PROG, 5α- and/or 5β-DHT, or E2. (C) Comparisons of 7α- and/or 7β-OH PREG synthesis and Cyp7b mRNA expression in the pineal gland of adults and chicks of both sexes (n = 8). **P < 0.01 vs. adult. (D) Comparisons of 7α- and/or 7β-OH PREG synthesis and Cyp7b mRNA expression among the pineal gland, cerebellum, and diencephalon of quail chicks of both sexes (n = 8). **P < 0.01 vs. cerebellum or diencephalon. (E) Comparisons of 7α- and 7β-OH PREG releases from the pineal gland, cerebellum, and diencephalon of male quail chicks by GC-MS (n = 6). ***P < 0.001 vs. cerebellum or diencephalon. (F) Comparisons of ALLO and/or EPI synthesis and Srd5a mRNA expression in the pineal gland of adults and chicks of both sexes (n = 8). **P < 0.01 vs. adult. (G) Comparisons of ALLO and/or EPI synthesis and Srd5a mRNA expression among the pineal gland, cerebellum, and diencephalon of quail chicks of both sexes (n = 8). ***P < 0.001 vs. cerebellum or diencephalon. (H) Comparisons of ALLO and EPI releases from the pineal gland, cerebellum, and diencephalon of male quail chicks by GC-MS (n = 6). **P < 0.01 vs. cerebellum or diencephalon. (I) Identified biosynthetic pathways of neurosteroids in the pineal gland. Each column and vertical line in B–H represent the mean ± SEM.