Objective To clarify the effects of androgens (testosterone and dihydrotestosterone, DHT) and ageing on gene expression of vasoactive intestinal polypeptide (VIP), assessed as the expression of VIP mRNA, in rat corpus cavernosum. Materials and methods The study comprised 160 male Sprague Dawley rats divided into group A (56 rats, 5 weeks old), group B (50 rats, 10 weeks old) and group C (54 rats, 58 weeks old). Groups A±C were subdivided, respectively, into subgroups 1 (intact controls), 2 (castrated), 3 (castrated but given testosterone undecanoate 25 mg/kg per month by intramuscular injection), 4 (castrated with testosterone undecanoate 50 mg/kg per month) and 5 (treated with ®nasteride 4.5 mg/kg per day, orally). At 4 and 10 weeks after these treatments half the rats were killed. Serum samples were taken for the measurement of total and free testosterone and DHT, using a radioimmunoassay. Penile samples (corpus cavernosum) were frozen in liquid nitrogen and stored at x80uC. VIP mRNA was estimated using a semiquantitative reverse-transcription polymerase chain reaction. Results There was no signi®cant difference in VIP mRNA in rat corpus cavernosum between intact control and castrated subgroups, or subgroups treated with ®nasteride, in groups A±C, including both the 4-and 10-week old animals (P>0.05). Penile VIP mRNA was unchanged at any dose of testosterone in the castrated subgroups in all groups (P>0.05). There was no signi®cant relationship between penile VIP mRNA and ageing (P>0.05). Conclusions The gene expression of VIP in rat corpus cavernosum is independent of androgens (testosterone and DHT) and ageing. Androgens probably induce penile erection by pathways other than VIP; ageing may have little effect on penile VIP mRNA.

ABSTRACT. Peanut is one of the most important oilseed crops in the world that provides a significant amount of lipids and protein for many people. The gynophore plays an important role in gynophore development after fertilization of the peanut ovule. MicroRNAs (miRNAs) play an important role in numerous developmental and physiological plant processes. Therefore, it is essential to analyze the miRNA sequences at different gynophore stages to explore and validate gene function. Multiple small RNAs were sequenced and collected from gynophore stages A1, A2, and A3 (5, 10, and 20 days of development, respectively) for further prediction. We obtained 266 known and 357 novel miRNAs from the three different stages. Stage A3 had the largest number of reads. Genes involved in the lignin catabolic process 2 Y. Shen et al. Genetics and Molecular Research 15 (4): gmr15048691were identified only at stage A1. The copper ion-binding process also specifically emerged at stage A1, whereas negative regulation of biological processes occurred only in stages A2 and A3. The genes related to growth were found only at stage A3, suggesting that the gynophore may contribute to rapid development of the gynophore at this stage. Our identification and assessment of miRNAs from different gynophore stages may serve as a basis for further studies of gynophore miRNA regulation mechanisms. Some biological processes were specifically regulated at different gynophore stages indicating that miRNAs play an important role in the gynophore development.