Wlodek M E, Westcott K T, Serruto A, O'Dowd R, Wassef L, Ho P W M, Moseley J M
Department of Physiology, University of Melbourne, Victoria 3010, Australia.
J Endocrinol. 2003 Aug;178(2):233-45. doi: 10.1677/joe.0.1780233.
Evidence implicates pivotal roles for parathyroid hormone-related protein (PTHrP) during lactation, including stimulation of mammary and pup growth. As spontaneously hypertensive rat (SHR) pups are growth restricted compared with the control Wistar Kyoto (WKY), we examined the relative roles of pup suckling and maternal lactational environment on pup growth, mammary PTHrP, and milk PTHrP and calcium concentrations. SHR pups were lighter compared with the control from 6 days. SHR mammary PTHrP content and milk PTHrP were lower but maternal plasma PTHrP was raised compared with WKY. SHR mammary morphological development was also impaired compared with control. Cross fostering growth-restricted pups onto WKY mothers increased pup weight in association with normal mammary function and higher milk PTHrP and calcium. Control pups suckling on an SHR mother had reduced body weight. Both cross fostering groups were associated with increased maternal and milk PTHrP concentrations, indicating the importance of suckling, together with a functional mammary gland. The results suggested that impaired SHR mammary function and milk PTHrP are associated with a reduced SHR postnatal growth. Our data also indicated that milk and mammary PTHrP are regulated by different mechanisms but that they are influenced by the maternal lactational environment and the suckling pup.
有证据表明甲状旁腺激素相关蛋白（PTHrP）在哺乳期发挥关键作用，包括促进乳腺和幼崽生长。由于与对照Wistar Kyoto（WKY）大鼠相比，自发性高血压大鼠（SHR）幼崽生长受限，我们研究了幼崽吮乳和母体泌乳环境对幼崽生长、乳腺PTHrP、乳汁PTHrP和钙浓度的相对作用。从6日龄起，SHR幼崽就比对照组轻。与WKY相比，SHR乳腺PTHrP含量和乳汁PTHrP较低，但母体血浆PTHrP升高。与对照组相比，SHR乳腺的形态发育也受到损害。将生长受限的幼崽寄养到WKY母亲身上，幼崽体重增加，同时乳腺功能正常，乳汁PTHrP和钙含量升高。在SHR母亲哺育下的对照幼崽体重减轻。两个寄养组的母体和乳汁PTHrP浓度均升高，表明吮乳以及功能性乳腺的重要性。结果表明，SHR乳腺功能受损和乳汁PTHrP与SHR出生后生长减缓有关。我们的数据还表明，乳汁和乳腺PTHrP受不同机制调节，但它们受母体泌乳环境和吮乳幼崽的影响。
