Category Archives: Hormone - Part 2

Hormone-Specific Inhibitory Influence: DISCUSSION(6)

PNGase digestion of free hCGa increased the dimerization efficiency of the deglycosylated a derivative to 64% by removing Asn52 oligosaccharides . Our data are consistent with these results, as the highest efficiency of equine gonadotropin subunit dimerization was obtained with … Continue reading

Hormone-Specific Inhibitory Influence: DISCUSSION(5)

This is supported by earlier studies with pituitary and placental free a-subunit preparations. The inability of bovine pituitary free a to combine with oLHp was attributed to the presence of an additional –ě-linked oligosaccharide attached to Thr43, which is not … Continue reading

Hormone-Specific Inhibitory Influence: DISCUSSION(4)

This implies a barrier to dimerization that is probably provided by the necessity to insert the a-subunit long loop L2 and its associated carbohydrate through the p-subunit seatbelt loop. Studies by Ruddon and colleagues demonstrated that the rate of hCG … Continue reading

Hormone-Specific Inhibitory Influence: DISCUSSION(3)

Recent nuclear magnetic resonance (NMR) studies have indicated that the Man(al-3)Man antenna is less flexible than the Man(al-6)Man branch . Addition of 2-3 monosaccharide residues to the more flexible Man(al-6)Man antenna in eFSHa Asn56 oligosaccharides offered increased steric hindrance by … Continue reading

Hormone-Specific Inhibitory Influence: DISCUSSION(2)

In our previous studies of equine gonadotropin oligosaccharides, we identified hormone-specific patterns of glycosylation at aAsn56 . Despite the fact that oligosaccharide mapping revealed a high degree of structural heterogeneity similar to that reported for eLHp and eCGp Asn13 carbohydrate … Continue reading

Hormone-Specific Inhibitory Influence: DISCUSSION(1)

Early studies involving glycoprotein hormone carbohydrate, consisting of comparison of the activities of native hormone preparations with those of derivatives that had been¬†extensively deglycosylated by chemical or enzymatic procedures, revealed that carbohydrate generally inhibited receptor binding but was necessary for … Continue reading

Hormone-Specific Inhibitory Influence: RESULTS(10)

Purified eFSHp hybrid preparations and purified eLHp hybrid preparations were tested together in the same granulosa cell FSH bioassay (Fig. 9). The relatively low response of these cells to eLH and eCG stimulation as compared to eFSH was similar to … Continue reading

Hormone-Specific Inhibitory Influence: RESULTS(9)

Inorderto determine whether or not aAsn56 oligosaccharides were responsible for the a subunit-mediated differences in FSH receptor-binding activity shown above, preparative reassociation of eLHpt was performed with N56dg-eLHa, N56dg-eFSHa, and N56dg-eCGa preparations, and the heterodimer fractions were purified bySuperdex 75 … Continue reading

Hormone-Specific Inhibitory Influence: RESULTS(8)

Six hybrid hormone preparations were obtained by combining either the eLHfbt or eCG|3t preparation with samples of native eLHa, eFSHa, and eCGa preparations. The heterodimer fractions were purified bySuperdex 75 chromatography and analyzed by hFSHR RLA (Fig. 7 and Table … Continue reading

Hormone-Specific Inhibitory Influence: RESULTS(7)

The eFSHa:eFSH(3 hybrid preparation was 71-77% asactiveas the eLHa:eFSH(3 preparation; this activity level proved significantly different in only one system, the CHO-hFSHR assay (Table 3), but was never significantly different from that of the eCGa:eFSH(3 preparation. In contrast to the … Continue reading

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