Expression of GH receptor mRNA in regenerating skeletal muscle of normal and hypophysectomized rats. An in situ hybridization study

1991 ◽  
Vol 125 (6) ◽  
pp. 595-602 ◽  
Author(s):  
Eva Jennische ◽  
Göran L. Andersson
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
In Situ Hybridization ◽  
Growth Hormone Receptor ◽  
Receptor Expression ◽  
Muscle Fibres ◽  
Receptor Mrna ◽  
Gh Receptor ◽  
Hypophysectomized Rats

Abstract. Expression of growth hormone receptor mRNA was investigated by in situ hybridization in skeletal muscle from normal and hypophysectomized rats during the first seven days of regeneration after ischemic injury. A digoxigenin-labelled RNA probe directed against the extracellular part of the rat GH receptor was used. In both normal and hypophysectomized rats distinct expression of GH receptor mRNA could be demonstrated in the regenerating muscle cells at the myoblast/myotube stage. The GH receptor expression appeared to decline with increasing maturation of the regenerated muscle fibres. In hypophysectomized rats, the regeneration process and the expression of GH receptor mRNA was delayed compared with that in normal animals. It is concluded that growth hormone may affect also the early phase of muscle regeneration in normal animals. To what extent lack of growth hormone contributes to the delayed regeneration observed in the hypophysectomized rats remains to be elucidated.

Expression of the IGF-II/mannose-6-phosphate receptor mRNA and protein in the developing rat

Development ◽  
1990 ◽  
Vol 109 (1) ◽  
pp. 67-73 ◽  
Author(s):  
P.V. Senior ◽  
S. Byrne ◽  
W.J. Brammar ◽  
F. Beck
Keyword(s):  
Skeletal Muscle ◽  
In Situ Hybridization ◽  
Receptor Expression ◽  
Receptor Mrna ◽  
Mrna Induction ◽  
Factor Ii ◽  
Mannose 6 Phosphate ◽  
Developing Rat ◽  
Lysosomal Transport

The insulin-like growth factor II (IGF-II) receptor is identical to the mannose-6-phosphate receptor (M-6-P), but its role as a somatomedin transducer is uncertain. IGF-II/M-6-P receptor expression was studied by in situ hybridization (ISH) in the developing rat. Expression occurs in extra-embryonic membranes at the time of IGF-II mRNA induction and later at paracrine/autocrine sites of IGF-II action (skeletal muscle and perichondrium) in the embryo. Highest levels of receptor mRNA occur in heart and major vessels. Postnatally transcription is strongly down-regulated. This suggests a role for the IGF-II/M-6-P receptor in IGF-II action or turnover during development distinct from its role in lysosomal transport.

Growth hormone receptor regulation in growth hormone-deficient dwarf rats

1993 ◽  
Vol 138 (2) ◽  
pp. 267-274 ◽  
Author(s):  
D. F. Carmignac ◽  
I. C. A. F. Robinson ◽  
B. Enberg ◽  
G. Norstedt
Keyword(s):  
Growth Hormone ◽  
Sex Difference ◽  
Gh Deficiency ◽  
Binding Capacity ◽  
Receptor Expression ◽  
Sexually Dimorphic ◽  
Mrna Levels ◽  
Receptor Mrna ◽  
Gh Receptor ◽  
Normal Males

ABSTRACT In the rat, many actions of GH depend upon the sexually dimorphic pattern of exposure to GH. Hepatic human GH (hGH) receptor binding differs between the sexes and is sensitive to GH deficiency, but this has mostly been studied in acutely hypophysectomized rats, which lack all pituitary hormones. We have used a strain of GH-deficient dwarf (Dw) rats to determine whether chronic GH deficiency alters the normal developmental pattern and sexually dimorphic expression of hepatic GH receptors. Adult female Dw rats had lower levels of 125I-labelled hGH binding (reflecting predominantly lactogenic receptors) than their normal counterparts whereas there was no difference between adult Dw and normal males; binding capacity increased from 25 days of age, becoming sexually dimorphic from 40 days to adulthood in both strains (% specific binding/mg protein: normal males 1·6 ± 0·3, normal females 13·2 ± 1·1, Dw males 2·1 ±0·4, Dw females 10·0 ± 0·6). In contrast, hepatic 125I-labelled bovine GH (bGH) binding (somatogenic receptors) was much lower, and similar in both Dw and normal animals. A sex difference in 125I-labelled bGH binding was only seen in adult animals, and was considerably less marked in Dw rats compared with normal animals (normal males 1·3 ±0·1, normal females 2·5 ± 0·2, Dw males 1·9 ± 0·2, Dw females 2·4 ± 0·2%/mg protein). Continuous hGH infusion stimulated growth in female Dw rats, and raised somatogenic and lactogenic GH binding (3·2 ± 0·4 and 19·6 ± 2·5%/mg protein) compared with sham-infused controls (2·4 ± 0·2 and 7·9 ± 0·6%/mg protein). Dw rats had significantly smaller amounts of hepatic GH receptor mRNA than normal rats, but there was no significant sex difference in GH receptor mRNA levels in the dwarfs. The pituitary GH deficiency in Dw rats was present at birth and the relative deficit remained constant despite large increases in pituitary GH that occurred from birth to maturity. Thus whilst hepatic GH receptor expression can be altered by GH in Dw rats, their chronic GH deficiency causing severe dwarfism is accompanied by only small differences in hepatic GH receptor expression. Journal of Endocrinology (1993) 138, 267–274

scholarly journals Cortisol increases growth hormone-receptor expression in human osteoblast-like cells

1998 ◽  
Vol 156 (1) ◽  
pp. 99-105 ◽  
Author(s):  
D Swolin-Eide ◽  
A Nilsson ◽  
C Ohlsson
Keyword(s):  
Growth Hormone ◽  
Control Culture ◽  
Receptor Expression ◽  
Serum Starvation ◽  
Maximal Effect ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Osteoblast ◽  
Receptor Mrna ◽  
Gh Receptor

It is well known that high levels of glucocorticoids cause osteoporosis and that physiologic levels of growth hormone (GH) are required for normal bone remodeling. It has been suggested that glucocorticoids regulate GH-responses via the regulation of GH-receptor expression. The aim of the present study was to investigate whether cortisol plays a role in the regulation of GH-receptor expression in cultured human osteoblasts. The effect of serum starvation and cortisol on GH-receptor expression was tested in human osteoblast (hOB)-like cells. Serum starvation for 24 h resulted in an increase in GH-receptor mRNA levels (90 +/- 1% over control culture). Cortisol increased GH-receptor mRNA levels in a dose-dependent manner with a maximal effect at 10(-6)M. The stimulating effect of cortisol on GH-receptor mRNA levels was time-dependent, reaching a peak 12 h after the addition of cortisol (126 +/- 29% over control culture) and remaining up to 12 h later. The increase in GH-receptor mRNA levels was accompanied by an increase in 125I-GH binding which reached a maximum at 24 h (196 +/- 87% over control culture). In conclusion, glucocorticoids increase GH-receptor expression in hOB-like cells. Further studies are needed to clarify whether glucocorticoid-induced regulation of the GH-receptor is important in human bone physiology.

Estrogen enhances growth hormone receptor expression and growth hormone action in rat osteosarcoma cells and human osteoblast-like cells

1997 ◽  
Vol 155 (1) ◽  
pp. 159-164 ◽  
Author(s):  
MC Slootweg ◽  
D Swolin ◽  
JC Netelenbos ◽  
OG Isaksson ◽  
C Ohlsson
Keyword(s):  
Growth Hormone ◽  
Cell Proliferation ◽  
Growth Hormone Receptor ◽  
Receptor Expression ◽  
Osteosarcoma Cell ◽  
Mrna Levels ◽  
Human Osteoblast ◽  
Osteosarcoma Cells ◽  
Gh Receptor ◽  
Hormone Receptor Expression

Postmenopausal bone loss is primarily due to estrogen deficiency. Recent clinical observation demonstrate that GH increases bone mass in GH deficient patients. The present study investigates whether estrogen regulates GH action and GH receptor expression in osteoblasts. 17 beta-estradiol or GH added to the culture medium as single substances did not influence rat osteosarcoma cell proliferation nor human osteoblast-like (hOB) cell proliferation. However, together they synergistically induced osteoblast proliferation (rat osteosarcoma cells 160.1 +/- 15.5% of control cells; human osteoblast-like cells 159.6 +/- 5.1% of control cells). 17 beta-estradiol stimulated 125I-GH binding and GH receptor (GHR) mRNA levels in rat osteosarcoma cells. The stimulatory effect of estradiol was time dependent, reaching a peak after 8 h of incubation with 17 beta-estradiol (binding 216.9 +/- 27.8% and mRNA 374.6 +/- 30.8% of control). The finding that estradiol stimulated 125I-GH binding was confirmed in human osteoblast-like cells. In these cells, 17 beta-estradiol (10(-12) M) increased 125I-GH binding to 203.8 +/- 3.6% of control levels. We conclude that estrogen stimulates GH activity as well as GH binding and GHR mRNA levels in osteoblasts. These findings indicate that estrogen potentiates the effect of GH at the receptor level.

Pituitary adenoma producing growth hormone and adrenocorticotropin: a histological, immunocytochemical, electron microscopic, and in situ hybridization study

1998 ◽  
Vol 88 (6) ◽  
pp. 1111-1115 ◽  
Author(s):  
Kalman Kovacs ◽  
Eva Horvath ◽  
Lucia Stefaneanu ◽  
Juan Bilbao ◽  
William Singer ◽  
...  
Keyword(s):  
Growth Hormone ◽  
In Situ Hybridization ◽  
Pituitary Adenoma ◽  
Immunoelectron Microscopy ◽  
Secretory Granules ◽  
Cell Types ◽  
Content Type ◽  
Separate Cell ◽  
Fine Print

✓ The authors report on the morphological features of a pituitary adenoma that produced growth hormone (GH) and adrenocorticotropic hormone (ACTH). This hormone combination produced by a single adenoma is extremely rare; a review of the available literature showed that only one previous case has been published. The tumor, which was removed from a 62-year-old man with acromegaly, was studied by histological and immunocytochemical analyses, transmission electron microscopy, immunoelectron microscopy, and in situ hybridization. When the authors used light microscopy, the tumor appeared to be a bimorphous mixed pituitary adenoma composed of two separate cell types: one cell population synthesized GH and the other ACTH. The cytogenesis of pituitary adenomas that produce more than one hormone is obscure. It may be that two separate cells—one somatotroph and one corticotroph—transformed into neoplastic cells, or that the adenoma arose in a common stem cell that differentiated into two separate cell types. In this case immunoelectron microscopy conclusively demonstrated ACTH in the secretory granules of several somatotrophs. This was associated with a change in the morphological characteristics of secretory granules. Thus it is possible that the tumor was originally a somatotropic adenoma that began to produce ACTH as a result of mutations that occurred during tumor progression.

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