Extended Aspects of Growth Hormone (GH) Action: GH Receptor (GHR) mRNA Expression in Various Bovine Tissues and Effects of a Long-Term Treatment with GH on GHR mRNA and on GH Binding in Liver.

Abstract

Abstract. The expression of the bovine growth hormone receptor (GHR) was detected in various tissues by a reverse transcription -polymerase chain reaction system (RT-PCR). For the quantification of the bovine 438 by GHR cDNA fragments a HPLC-UV detection system was used. bGHR amplificates were well detectable in liver from cows, heifers and in fetal liver. bGHR expression was also demonstrated in mammary gland, kidney and in adipose tissue. Lower but significant amounts of bGHR amplificates were obtained in skeletal muscle and in rumen villi, indicating a potential new mode of action of GH via affecting the gastrointestinal tract. bGHR mRNA was detected in various female and male reproductive tissues, i.e. in uterus, oviduct, corpus luteum, and in the vesicular gland. No bGHR expression was detectable in testes from adult bulls. A longterm treatment of heifers with a slow-release preparation of bovine growth hormone had no effect on either bGHR-mRNA expression in liver or on GH binding capacity on liver membrane preparations. These results demonstrate that the RT-PCR system together with a HPLC-UV detection system provides a useful strategy to study GHR expression and regulation in different tissues under various conditions.

Cellular localisation of GH receptor in the bovine mammary gland during mammogenesis, lactation and involution

“…In contrast, more recent work using Northern blot and in situ hybridisation (Glimm et al 1992), PCR and ribonuclease protection assay (Hauser et al 1990, Röpke et al 1994) demonstrated GH receptors in bovine mammary gland. Hauser et al (1990) cloned cDNA for the bovine GH receptor out of a cDNA library prepared from the liver of a pregnant Holstein heifer.…”

“…In view of the disagreement between conventional radioligand-binding studies (Gertler et al 1984, Akers 1985, Kazmer et al 1986, Keys & Djiane 1988 and the unequivocal demonstration of the GH receptor mRNA by several molecular biological techniques, such as Northern blotting and PCR (Röpke et al 1994), we have sought to demonstrate and localise the bovine mammary gland GH receptor. We found a widespread distribution of GH receptor in the bovine mammary gland cells, including glandular epithelium and stromal components.…”

“…(2) Many cell types, which are significant components of the bovine mammary gland, such as fibroblasts, adipocytes, T-lymphocytes and smooth muscle cells, have been shown to possess GH receptors (Isaksson et al 1985). (3) GH receptor mRNA has been demonstrated and characterised in lactating bovine tissue using Northern blots, in situ hybridisation (Glimm et al 1992) and RT-PCR (Röpke et al 1994).…”

Stimulatory effect of growth hormone on in vitro maturation of bovine oocytes is exerted through cumulus cells and not mediated by IGF-I

“…Immunohistochemical analysis of the ovary using a rat monoclonal antibody that binds to the extracellular domain of the GHR showed positive staining of the corpus luteum, whereas surrounding stroma, follicles, and blood vessels were negative . Expression of GHR mRNA was clearly detectable in luteal tissue (Ropke et al, 1994;Lucy et al, 1993), but difficult to detect in follicles of all size classes .…”

Comparative Activities of Growth Hormone and Luteinizing Hormone in the Direct Stimulation of Local Release of Progesterone from Microdialyzed Ovine Corpora Lutea In Vivo.

“…Indeed, in vitro studies have described direct actions of GH on follicular and luteal cell functions; GH, either alone or accompanied by follicle stimulating hormone (FSH) or estradiol-17β (E 2 ) [7][8][9][10][11], stimulates granulosa cell steroidogenesis, and with insulin, stimulates the proliferation of granulosa cells [9]; GH also stimulates P production by human luteal cells [12], and the release of P from the microdialyzed bovine CL in vitro [13]. On the other hand, studies on the GH receptor in the bovine ovary have indicated that the CL is the major site for GH receptor protein and its mRNA in the ovary, whereas the follicles have almost no GH receptors [14,15]. These data suggest that GH may be a direct regulator of luteal function, while GH may facilitate follicular function by causing an increase of liver-derived insulin-like growth factor-I (IGF-I) concentrations in the circulation.…”