scholarly journals Can Atlantic salmon smolt twice? Endocrine and biochemical changes during smolting

2000 ◽  
Vol 57 (10) ◽  
pp. 1969-1976 ◽  
Author(s):  
J Mark Shrimpton ◽  
Björn Thrandur Björnsson ◽  
Stephen D McCormick
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Atpase Activity ◽  
First Year ◽  
Physiological Changes ◽  
Lower Mode ◽  
Hormone Levels ◽  
Corticosteroid Receptor ◽  
Cortisol Levels ◽  
Saltwater Tolerance

Smolting is characterized by morphological and physiological changes, some of which are reversible if fish remain in freshwater. Whether fish that smolt in the first year will repeat physiological changes associated with smolting a second time is not known. To assess whether Atlantic salmon (Salmo salar) can smolt more than once, we sampled hatchery-reared Atlantic salmon at monthly intervals for 2 years beginning the fall after hatching. Fish showed differences in rate of growth and were easily differentiated by size into upper mode (UM) and lower mode (LM) by the first fall. In the first spring, gill Na+,K+-ATPase activity of UM and LM fish increased six- and three-fold, respectively. Plasma growth hormone levels in spring were significantly elevated in UM fish but not in LM. Plasma cortisol levels changed little and gill corticosteroid receptor concentration did not differ between the groups. During the summer, gill Na+,K+-ATPase activity declined in both groups and remained low until the next spring. The second spring, growth hormone levels did not increase significantly and cortisol levels increased. The increase in gill Na+,K+-ATPase activity and cortisol and high saltwater tolerance indicate that UM Atlantic salmon can smolt in two consecutive years.

Circulating growth hormone levels in Atlantic salmon smolts following seawater transfer: effects of photoperiod regime, salinity, duration of exposure and season

Aquaculture ◽  
1998 ◽  
Vol 168 (1-4) ◽  
pp. 121-137 ◽  
Author(s):  
Björn Thrandur Björnsson ◽  
Gudmundur Valur Stefansson ◽  
Åse I Berge‡ ◽  
Tom Hansen ◽  
Sigurd O Stefansson
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Transfer Effects ◽  
Hormone Levels ◽  
Photoperiod Regime

Osmoregulation, feed intake, growth and growth hormone levels in 0+ Atlantic salmon (Salmo salar L.) transferred to seawater at different stages of smolt development

Aquaculture ◽  
2003 ◽  
Vol 222 (1-4) ◽  
pp. 167-187 ◽  
Author(s):  
Arne M. Arnesen ◽  
Hilde Toften ◽  
Thorleifur Agustsson ◽  
Sigurd O. Stefansson ◽  
Sigurd O. Handeland ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Feed Intake ◽  
Hormone Levels ◽  
Atlantic Salmon Salmo Salar

Genetic differences in physiology, growth hormone levels and migratory behaviour of Atlantic salmon smolts

2001 ◽  
Vol 59 (1) ◽  
pp. 28-44 ◽  
Author(s):  
C. Nielsen ◽  
G. Holdensgaard ◽  
H. C. Petersen ◽  
B. Th. Bjornsson ◽  
S. S. Madsen
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Genetic Differences ◽  
Migratory Behaviour ◽  
Hormone Levels

Growth, Parr–Smolt Transformation, and Changes in Growth Hormone of Atlantic Salmon (Salmo salar) Reared under Different Photoperiods

1991 ◽  
Vol 48 (11) ◽  
pp. 2100-2108 ◽  
Author(s):  
Sigurd O. Stefansson ◽  
Björn Th. Bjömsson ◽  
Tom Hansen ◽  
Carl Haux ◽  
G. Lasse Taranger ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Rate ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Continuous Light ◽  
Plasma Growth Hormone ◽  
Hormone Levels ◽  
Light Regimes ◽  
Atlantic Salmon Salmo Salar ◽  
Natural Photoperiod

Potential 1+ smolts of Atlantic salmon (Salmo salar) were reared under three light regimes: simulated natural photoperiod (LDN), continuous light (LD24:0), or a combination of continuous, low-intensity background light and a superimposed simulated natural photoperiod (dual photoperiod, LDD). Growth rate in freshwater was enhanced by LD24:0 and LDD, and changes associated with smoking (increased salinity tolerance, reduced condition coefficient) were advanced under LD24:0. Plasma growth hormone levels were initially high on LD24:0 and LDD whereas on LDN, plasma growth hormone levels increased gradually from February through April. Overall GH levels were negatively correlated with condition coefficient during the final stages of smoking. After 16 mo in seawater, there were no significant size differences among the groups. The incidence of sexual maturation as postsmolts was higher in the LD24:0 and LDD groups whereas the incidence of grilsing was higher in LDN. Results demonstrate the significant influence of photoperiod on growth and smoking in Atlantic salmon. An abrupt increase to continuous light in winter may be sufficient to advance important aspects of the parr–smolt transformation. Dual photoperiod may be a way to combine the increased growth rate observed under continuous light and the normal parr–smolt transformation associated with natural photoperiod.

scholarly journals A Clinical Audit on Diagnosis and Management of Hypopituitarism in Scarborough General Hospital

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A621-A621
Author(s):  
Santhosh Abraham ◽  
Emmanuel Ssemmondo ◽  
Anis Abobaker ◽  
David Humphriss ◽  
Tadeusz Pawlak
Keyword(s):  
Growth Hormone ◽  
Hormone Replacement Therapy ◽  
Replacement Therapy ◽  
General Hospital ◽  
Hormone Replacement ◽  
Stimulation Test ◽  
Endocrine Society ◽  
Hormone Levels ◽  
Diagnosis And Management ◽  
Cortisol Levels

Abstract Objectives: The main objective was to evaluate the use and compliance to the guidelines issued by the Endocrine Society in diagnosis and management of hypopituitarism and their impact on the clinical practice in Scarborough General Hospital (SGH). Design: A retrospective review of secondary data of patients with a diagnosis of hypopituitarism in SGH. Methodology: The data was collected from both patients’ case notes and electronic medical records. Data analysis was performed using Microsoft excel. Results: 18 patients with the diagnosis of Hypopituitarism were identified. 5 patients were females and 13 were males. 11 patients aged between 60-80 years, 4 patients were between 51-60 years and 3 patients were between 31-50 years. All the patients had low cortisol levels; however, cortisol was checked at 9AM in only 4 patients. All the patients had their thyroid stimulating hormone levels checked, which were low in all of them. Free T4 levels were normal in 2 patients, and low in 16 patients. 17 patients had low follicular stimulating hormone levels, whereas 15 had low luteinising hormone levels. Testosterone levels were checked in 9 male patients out of which 7 had low levels. Insulin-like growth factor-1(IGF1) was done in all patients and levels were low in 10 patients. All those with low IGF1 had glucagon stimulation test. Serum sodium levels were low in 3 patients and high in 5 patients. Plasma osmolality was only checked in 8 patients (was high in 5 patients). Urine osmolality was checked in 10 patients, and it was low in 5 patients. Brain MRI was performed in 16 patients, and 2 patients had brain CT. The most common cause of hypopituitarism was non-functioning pituitary adenoma (44.4%), and the least common causes were empty Sella syndrome (5.6%) and craniopharyngioma (5.6%). All patients received glucocorticoid replacement therapy, 17 received thyroid hormone replacement therapy, 8 received testosterone replacement therapy, 3 received desmopressin (DDAVP) treatment, and one patient received growth hormone replacement therapy. Conclusion: This Audit shows that our practice in diagnosis and management of hypopituitarism is mostly in line with the recommendation of the Endocrine Society. However, cortisol levels were not always measured at 9:00 am and we are not compliant with performing Growth Hormone stimulation test in every patient.

Elevated growth hormone levels in stunted Atlantic salmon, Salmo salar

Aquaculture ◽  
1988 ◽  
Vol 73 (1-4) ◽  
pp. 275-281 ◽  
Author(s):  
Björn Th. Björnsson ◽  
Tsuyoshi Ogasawara ◽  
Tetsuya Hirano ◽  
Jonathan P. Bolton ◽  
Howard A. Bern
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Hormone Levels ◽  
Atlantic Salmon Salmo Salar

Glucose, growth hormone, somatomedin, cortisol and ACTH changes in the plasma of unanaesthetised pig foetuses following intravenous insulin administration in utero

1983 ◽  
Vol 104 (2) ◽  
pp. 240-245 ◽  
Author(s):  
G. S. G. Spencer ◽  
G. J. Garssen ◽  
B. Colenbrander ◽  
A. A. Macdonald ◽  
M. M. Bevers
Keyword(s):  
Growth Hormone ◽  
Plasma Glucose ◽  
In Utero ◽  
Insulin Administration ◽  
Hormone Levels ◽  
Intravenous Insulin ◽  
Insulin Tolerance ◽  
Cortisol Levels

Abstract. Insulin tolerance tests were carried out in chronically catheterised foetal pigs. The experiment was carried out 7 days after catheterisation. The foetuses were, therefore, considered to be free from the effects of anaesthetics and stress. Under these conditions growth hormone levels were high compared with post-natal growth hormone levels but, under the favourable conditions in this study, both growth hormone and ACTH levels were lower than those found in anaesthetised or stressed foetuses. By contrast, cortisol levels were somewhat higher than those mentioned in previous reports. Somatomedin activity measured by post-natal cartilage bioassay was low. Following iv insulin administration there was a marked depression in plasma glucose (P < 0.01), an elevation in growth hormone (P < 0.05) and an increase in ACTH (P < 0.01). Levels of cortisol and somatomedins did not change significantly. From these data it is concluded that insulin is an hypoglycaemic factor in the foetal pig and that, for the most part, the foetal pig pituitary responds to an insulin challenge in a similar way to the post-natal pig.

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