Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 31, 1998
Publication Date: N/A
Technical Abstract: Direct effects of LH and FSH on immune tissues have been reported. The presence of LH, but not FSH, receptors has been demonstrated in immune tissues. The objective of the present study was to evaluate the presence and developmental regulation of LH and FSH receptor mRNAs in neonatal pig thymus and spleen. PCR primers were designed for amplification of LH and FSH receptor cDNA produced from testicular RNA. The resulting PCR product were cloned for purposes of cRNA probe synthesis. The identities of the cloned cDNAs were confirmed by dideoxy termination sequencing. Specific LH and FSH receptor mRNA were readily detectable by northern blot analysis of pooled RNA samples from testis, thymus, and spleen (8 young pigs per tissue). LH and FSH receptor transcripts of sizes similar to those previously reported were observed in all tissues. Male piglets were sacrificed for tissue collection at 1, 7, 14, 21, 28, 35, and 42 days of age (n=8/age group). Slot-blot hybridization assays were performed on total RNA from thymus and spleen. Data were quantitated by densitometry, followed by normalization to 28S ribosomal RNA levels. LH receptor mRNA levels were higher in thymus than in spleen (3.24 +/ .49 vs 1.96 +/ .1 relative units (RU), respectively; P<.0001), but did not change with age in either tissue (P>.2). Similarly, expression of FSH receptor was elevated in thymus, relative to spleen (.68 +/ .08 vs .38 +/ .03 RU, P = .003), but did not vary among age groups (P>.5). These data support the hypothesis that gonadotropins may exert direct effects on immune tissues through gonadotropin-specific receptors. To our knowledge, this is the first evidence for FSH receptor gene expression in immune tissues of any species.