Relationship Between Ultradian Rhythms of the Sleep-Wakefulness Cycle and Growth Hormone and Corticosterone Secretion in Rats

1985 ◽  
pp. 61-76
Author(s):  
F. Kimura ◽  
C. Praputpittaya ◽  
N. Mitsugi ◽  
R. Hashimoto ◽  
R. Suzuki
Keyword(s):  
Growth Hormone ◽  
Ultradian Rhythms ◽  
Corticosterone Secretion

Circadian and ultradian rhythms of peripheral growth hormone concentrations in lactating dairy cows

1995 ◽  
Vol 12 (3) ◽  
pp. 247-256 ◽  
Author(s):  
A.M. Lefcourt ◽  
J. Bitman ◽  
D.L. Wood ◽  
R.M. Akers
Keyword(s):  
Growth Hormone ◽  
Dairy Cows ◽  
Ultradian Rhythms ◽  
Lactating Dairy Cows

Secretory pattern of canine growth hormone

1987 ◽  
Vol 252 (2) ◽  
pp. E268-E272
Author(s):  
M. B. French ◽  
P. Vaitkus ◽  
E. Cukerman ◽  
A. Sirek ◽  
O. V. Sirek
Keyword(s):  
Growth Hormone ◽  
Peak Plasma ◽  
Spectral Estimation ◽  
Fast Fourier Transformation ◽  
Ultradian Rhythms ◽  
Frequency Range ◽  
Transformation Techniques ◽  
Power Spectral ◽  
Frequency Components ◽  
Secretory Pattern

Our aim was to define the secretory pattern of growth hormone (GH) under basal conditions in fasted, conscious, male dogs accustomed to handling. Blood samples were withdrawn from a cephalic vein at 15-min intervals. In this way, any ultradian rhythms, if present, could be detected within the frequency range of 0.042-2 cycles/h. In addition, samples were drawn at either 1- or 2.5-min intervals for 2.5 or 5 h to determine whether frequency components greater than 2 cycles/h were present. GH was measured by radioimmunoassay and the raw data were submitted to time series analysis employing power spectral estimation by means of fast Fourier transformation techniques. Peak plasma levels were up to 12 times higher than the baseline concentration of approximately 1 ng/ml. Spectral analysis revealed an endogenous frequency of 0.22 cycles/h, i.e., a periodicity of 4.5 h/cycle. The results indicate that under basal conditions the secretory bursts of canine GH are limited to one peak every 4.5 h.

scholarly journals Characterization of Nocturnal Ultradian Rhythms of Melatonin in Children with Growth Hormone-Dependent and Independent Growth Delay1

2001 ◽  
Vol 86 (3) ◽  
pp. 1181-1187
Author(s):  
A. Muñoz-Hoyos ◽  
R. Jaldo ◽  
A. Molina-Carballo ◽  
G. Escames ◽  
M. Macías ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Ultradian Rhythms

scholarly journals Effects of Growth Hormone Receptor Ablation in Corticotropin-Releasing Hormone Cells

2021 ◽  
Vol 22 (18) ◽  
pp. 9908
Author(s):  
Willian O. dos Santos ◽  
Daniela O. Gusmao ◽  
Frederick Wasinski ◽  
Edward O. List ◽  
John J. Kopchick ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Food Intake ◽  
Growth Hormone Receptor ◽  
Acute Stress ◽  
Corticotropin Releasing Hormone ◽  
Male And Female ◽  
Releasing Hormone ◽  
Female Mice ◽  
Physiological Importance ◽  
Corticosterone Secretion

Corticotropin-releasing hormone (CRH) cells are the dominant neuronal population responsive to the growth hormone (GH) in the paraventricular nucleus of the hypothalamus (PVH). However, the physiological importance of GH receptor (GHR) signaling in CRH neurons is currently unknown. Thus, the main objective of the present study was to investigate the consequences of GHR ablation in CRH-expressing cells of male and female mice. GHR ablation in CRH cells did not cause significant changes in body weight, body composition, food intake, substrate oxidation, locomotor activity, glucose tolerance, insulin sensitivity, counterregulatory response to 2-deoxy-D-glucose and ghrelin-induced food intake. However, reduced energy expenditure was observed in female mice carrying GHR ablation in CRH cells. The absence of GHR in CRH cells did not affect anxiety, circadian glucocorticoid levels or restraint-stress-induced corticosterone secretion and activation of PVH neurons in both male and female mice. In summary, GHR ablation, specifically in CRH-expressing neurons, does not lead to major alterations in metabolism, hypothalamic–pituitary–adrenal axis, acute stress response or anxiety in mice. Considering the previous studies showing that central GHR signaling regulates homeostasis in situations of metabolic stress, future studies are still necessary to identify the potential physiological importance of GH action on CRH neurons.

Association of pituitary adenoma with neuronal christoma: A TEM study

1994 ◽  
Vol 52 ◽  
pp. 232-233
Author(s):  
Eva Horvath ◽  
Kalman Kovacs ◽  
B. W. Scheithauer ◽  
R. V. Lloyd ◽  
H. S. Smyth
Keyword(s):  
Growth Hormone ◽  
Pituitary Adenoma ◽  
Pituitary Tumor ◽  
Nervous Tissue ◽  
Alternative Explanation ◽  
Growth Hormone Releasing Hormone ◽  
Cell Hyperplasia ◽  
Releasing Hormone ◽  
Secretory Neurons

The association of a pituitary adenoma with nervous tissue consisting of neuron-like cells and neuropil is a rare abnormality. In the majority of cases, the pituitary tumor is a chromophobic adenoma, accompanied by acromegaly. Histology reveals widely variable proportions of endocrine and nervous tissue in alternating or intermingled patterns. The lesion is perceived as a composite one consisting of two histogenetically distinct parts. It has been suggested that the neuronal component, morphologically similar to secretory neurons of the hypothalamus, may initiate adenoma formation by releasing stimulatory substances. Immunoreactivity for growth hormone releasing hormone (GRH) in the neuronal component of some cases supported this view, whereas other findings such as consistent lack of growth hormone (GH) cell hyperplasia in the lesions called for alternative explanation.Fifteen tumors consisting of a pituitary adenoma and a neuronal component have been collected over a 20 yr. period. Acromegaly was present in 11 patients, was equivocal in one, and absent in 3.

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