Caprine luteinizing hormone isoforms during the follicular phase and anestrus

Identification of Four SNPs in LHB Gene and Their Associations with Sperm Qualities of Chinese Buffaloes

Luteinizing hormone beta polypeptide (LHB) gene has been considered important for sexual behavior and has associations with sperm quality. In this study, four SNPs (g.276 T>C, g.377A>C, g.401T>C, and g.412A>G) were detected in the LHB gene of 165 water buffaloes by direct sequencing and identification of overlap peaks, each of which was associated with at least one sperm quality trait of ejaculate volume, sperm concentration, post-thaw sperm motilities, and sperm abnormalities by chi-square analysis. Among them, g.276 T>C was associated with ejaculate volume (F = 2.857, p < 0.05), sperm concentration (F = 2.052, p < 0.05), and post-thaw sperm motilities (F = 3.480, p < 0.05); g.377A>C was related to ejaculate volume (F = 4.178, p < 0.05), g.401T>C had a marker effect on sperm abnormalities (F = 3.332, p < 0.05), g.412A>G was associated with sperm concentration (F = 3.579, p < 0.05), and sperm abnormalities (F = 3.408, p < 0.05). Furthermore, four haplotypes (H1: ACG, H2: CCG, H3: CTA, H4: CCA) were generated by linkage disequilibrium analysis, which composed seven genotypes. Among them, the buffaloes with combined genotype H2H2 had the higher ejaculate volume and the individuals with the combined haplotypes H1H4 had higher sperm concentration. In summary, our study showed that there was a significant association between SNPs of LHB gene and Chinese water buffalo sperm quality traits. To the best of our knowledge, this is the first report addressing the associations between the SNPs in the LHB gene and the sperm qualities of Chinese buffaloes.

Effect of ovine luteinizing hormone (oLH) charge isoforms on VEGF and cAMP production

Although an increase in VEGF expression and synthesis in association with LH has been established; it is unknown if all LH isoforms act similarly. This study evaluated the production of cAMP and VEGF among LH isoforms in two in vitro bioassays. The LH was obtained from hypophyses and the group of isoforms was isolated by chromatofocusing. cAMP production was assessed using the in vitro bioassay of HEK-293 cells and VEGF production was evaluated in granulosa cells. Immunological activity was measured with a homologous RIA. Immunoactivity and bioactivity for each isoform were compared against a standard, by estimating the IC50 and the EC50. The basic isoforms were more immunoactive than the standard. The neutral and the moderately acidic had an immunological activity similar to the standard. The acidic isoform was the least immunoreactive. cAMP production at the EC50 dose was similar among the basic isoforms, the moderately acidic and the standard; for the neutral and the acidic, the EC50 dose was higher. It was observed that compared with the control, VEGF production at the lowest LH dose was no different in the standard and each isoform. In the intermediate dose, a positive response was caused in the standard and the neutral and basic isoforms. Although the acidic isoform showed a dose-dependent response, it was not significant relative to the control. In conclusion, the basic isoform generated the greatest cAMP and VEGF production, similar to the reference standard, and the acidic the smallest.

Progesterone and the distribution of pituitary gonadotropin isoforms in cattle

The objective of the present study was to determine the relative proportion of gonadotropin isoforms in bovine pituitary glands affected by progesterone. Twelve postpubertal heifers (Swiss-Zebu) were assigned to three groups (n=4): intact animals in the luteal phase of the estrous cycle (diestrus group); ovariectomized heifers with (OVXP) or without progesterone treatment (OVX). Prior to pituitary gland collection, a blood sample was taken from each animal to determine the circulating progesterone concentration. Pituitary protein extractions processed by chromatofocusing were eluted with a pH gradient ranging from 10.5 to 3.5. The LH and FSH eluent was grouped on the basis of the following three criteria: (1) as either a basic (pH>or=7.5), neutral (pH 7.4-6.5) and acid (pH<or=6.4); (2) according to the pH unit (pH>or=10.5-3.5); (3) on the basis of distinct isoforms 12 peaks of which (A-L) were identified for LH and 11 (I-XI) for FSH. The analysis by range of pH and by pH of elution in the OVX and OVXP groups showed no difference in the LH and FSH isoform ratio, but diestrus cattle differs having a greater ratio (p<0.05) of basic LH isoforms (87.5+/-0.4%) and lesser ratio (p<0.05) of acid isoforms (5.4+/-0.7%). In the diestrus group, the ratio of acid FSH isoform increased (62.1+/-1.7%), while neutral isoforms decreased (5.7+/-0.4%, P<0.05). The analysis by isoform type of LH revealed a greater proportion of isoforms C (pH 9.4) and E (pH 9.0) in the groups with circulating progesterone when compared to the OVX group. The heterogeneity of FSH was quantitatively similar in most isoforms in the three groups, with the exception of the predominant isoform (VIII, pH 4.9) that was more abundant in the diestrus group (p<0.05). These results indicate that progesterone with other gonad factors influence the pituitary glicosylation altering the relative proportions of gonadotropin isoforms.