Expression of lymphocyte-derived growth hormone (GH) and GH-releasing hormone receptors in aging rats

Abstract

In the present study, we show that higher levels of lymphocyte GH are expressed in spleen cells from aging animals compared to young animals. Further, leukocytes from primary and secondary immune tissues and splenic T and B cells from aging rats all express higher levels of GHRH receptors compared to younger animals. Bone marrow and splenic T cells express the highest levels of GHRH receptor in aging animals. Spleen cells from aging animals showed no significant change in proliferation or GH induction after treatment with GHRH. Taken together, the data for the first time show alterations in GH synthesis and expression of the GHRH receptor on cells of the immune system that may play a role in the immune response in aging.

Improvement of cardiac and systemic function in old mice by agonist of growth hormone‐releasing hormone

“…It is well known that both progenitor cells and immune cells are affected by aging (Qin et al, 2016). Leukocytes from aging rats express higher levels of GHRH receptors in comparison with younger animals (Weigent, 2013). There is evidence that the GHRH/GH/IGF-1 axis is involved in modulating immune function (Ikushima et al, 2003;Kelley, 1990).…”

Regulation of Vascular Calcification by Growth Hormone–Releasing Hormone and Its Agonists

“…Besides its expression on the pituitary cells, GHRH and its receptors are also detected on other cells including fibroblasts 17 , cardiomyocytes 18 , and mesenchymal stem cells (MSCs) 19 . GHRH-Rs decrease with age in most but not all the tissues studied 20–22 . Synthetic agonists of GHRH (GHRH-A), with increased stability compared to the native GHRH peptide 16, 23 , have been utilized to treat experimental diabetes mellitus 24 , myocardial infarction 18, 25 , and lung damage 26 in animal models.…”

Thyrotropin-Releasing Hormone (TRH) and Somatostatin (SST), but not Growth Hormone-Releasing Hormone (GHRH) nor Ghrelin (GHRL), Regulate Expression and Release of Immune Growth Hormone (GH) from Chicken Bursal B-Lymphocyte Cultures

“…It has been described that GHRH is the main stimulatory regulator of pituitary GH expression and secretion [47], and it has also been reported to stimulate GH expression in chicken testis [48] and in quail immortalized neuroretinal (QNR/D) cells [49]. The expression of GHRH-R was previously reported in thymocytes and splenocytes of rats [50,51], fish [52], and in human T-lymphocytes [53]. Interestingly, neither GHRH nor GHRH receptor mRNAs, nor GHRH-R protein, were detected in chicken BBLs, in accordance with previous findings, where the absence of GHRH and GHRH-R in the chicken spleen was reported [41,54].…”