306. Testicular growth factor expression after hemicastration in the neonatal boar

The molecular mechanisms associated with testicular hypertrophy after hemicastration are poorly understood. Sertoli cells in culture underwent increased proliferation when exposed to fibroblast growth factor-2 (FGF2)1 and transforming growth factor-α (TGFα).2 To determine whether FGF2 and TGFα expression is upregulated during accelerated testicular growth after hemicastration in the boar animals were assigned to (a) control (n = 12), no treatment; (b) hemicastrated (n=14), left testis removed on Day 10 after birth. The right testis was removed from half the control and hemicastrated boars, respectively, on Days 15 and 20 after birth. RNA was extracted from sections of frozen testis, cDNA synthesised using TaqMan® Reverse Transcription, and real-time PCR performed. FGF2 expression was determined using forward (5′GTG TTA CAG ACG AGT GTT TCT TTT TTG3′), internal (5′acg act gga atc taa t3′) and reverse (5′TTC CTC GAC CGG TAA GTA TTG TAG T3′) primers. TGFα expression was similarly determined using forward (5′GGC TGT CCT CAT CAT CAC ATG T3′), internal (5′tgc tga tac act gct gc3′) and reverse (5′CGG CAC CAC TCA CAG TGT TT3′) primers. Data were analysed by ANOVA and LSD test (testis weight) and unpaired two-tailed t-tests assuming equal variance (FGF2, TGFα). There was no difference (P > 0.05) in testis weight between hemicastrated (3.9 ± 0.3 g; mean ± SEM) and control (3.6 ± 0.5 g) boars on Day 5 but on Day 10 hemicastrated boars had a greater (P = 0.01) testis weight (6.2 ± 0.8 g) than controls (4.3 ± 0.4 g). There were no differences (P > 0.05) between control and hemicastrated boars in TGFα or FGF2 expression on Days 5 and 10. It is concluded from the findings that upregulation of TGFα or FGF2 gene expression is not required for testicular hypertrophy subsequent to hemicastration in the neonatal boar. (1)Biol Reprod (1987); 37: 665–674.(2)Mol Cell Endocrinol (2001); 181: 221–227.