Haro L S, Singh R N, Lewis U J, Martinez A O, Galosy S S, Staten N R, Krivi G G
Division of Life Sciences, University of Texas at San Antonio 78249, USA.
Biochem Biophys Res Commun. 1996 May 15;222(2):421-6. doi: 10.1006/bbrc.1996.0760.
The carboxyl-terminal hGH fragment, hGH44-191, displays diabetogenic activity. To understand whether this biological activity is mediated through somatogenic or lactogenic receptors, we investigated the ability of hGH44-191 to bind both receptor classes. We found that hGH44-191 could not compete with [125I]hGH or [125I]bGH for bovine liver somatogenic binding sites. Additionally, hGH44-191 could not displace [125I]hGH from the somatogenic receptor sites when human liver microsomes were used as the receptor source. In contrast, hGH44-191 effectively competed with [125I]hGH for lactogenic receptor sites of lactating mammary gland microsomes and of bovine liver microsomes. In summary, hGH44-191 does not bind to somatogenic receptors but does not bind to lactogenic receptors. These data suggest that the biological actions of hGH44-191 could be mediated through lactogenic receptors.
羧基末端的人生长激素片段hGH44 - 191具有致糖尿病活性。为了解这种生物活性是否通过生长激素受体或催乳激素受体介导，我们研究了hGH44 - 191与这两类受体结合的能力。我们发现，hGH44 - 191不能与[125I]hGH或[125I]bGH竞争牛肝生长激素结合位点。此外，当用人肝微粒体作为受体来源时，hGH44 - 191不能从生长激素受体位点取代[125I]hGH。相反，hGH44 - 191能有效地与[125I]hGH竞争泌乳乳腺微粒体和牛肝微粒体的催乳激素受体位点。总之，hGH44 - 191不与生长激素受体结合，但能与催乳激素受体结合。这些数据表明，hGH44 - 191的生物学作用可能通过催乳激素受体介导。
