The effect of Ca2+ levels on in vitro prolactin release from the rostral pars distalis of coho salmon (Oncorhynchus kisutch)

1983 ◽  
Vol 61 (3) ◽  
pp. 682-684 ◽  
Author(s):  
D. J. MacDonald ◽  
B. A. McKeown
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Pars Distalis ◽  
Prolactin Release ◽  
Prolactin Synthesis ◽  
Rostral Pars Distalis

The effect of varying media Ca2+ levels on prolactin synthesis and release was investigated in vitro using the rostral pars distalis of coho salmon (Oncorhynchus kisutch). It was found that media Ca2+ is required for release and that maximum release occurred near physiological levels for plasma-ionized Ca2+ in salmonids. Both higher and lower levels of media Ca2+ were found to release less prolactin.

In vitro inhibition of pituitary prolactin synthesis and release by hypothalamic extract

1963 ◽  
Vol 205 (2) ◽  
pp. 213-218 ◽  
Author(s):  
P. K. Talwalker ◽  
A. Ratner ◽  
J. Meites
Keyword(s):  
Cerebral Cortex ◽  
Anterior Pituitary ◽  
Acid Extract ◽  
Prolactin Release ◽  
Lysine Vasopressin ◽  
In Vitro Inhibition ◽  
Hormone Inactivation ◽  
Prolactin Synthesis ◽  
Pituitary Prolactin

When rat anterior pituitary (AP) was incubated at 37.5 C in a Dubnoff metabolic shaker for 2 hr, 169% more prolactin was found in the combined medium and AP than in nonincubated AP. When AP was incubated together with homogenate or acid extract of rat hypothalamus, prolactin levels in the medium and AP were markedly decreased (36–75%), indicating inhibition of synthesis and release. Acid extract of rat cerebral cortex had no effect on prolactin synthesis or release. Incubation of ovine or rat prolactin, with or without hypothalamus, did not decrease prolactin activity, demonstrating that hypothalamic inhibition of AP prolactin production was not due to hormone inactivation. Acetylcholine, epinephrine, norepinephrine, serotonin, histamine, substance P, oxytocin, and arginine or lysine vasopressin had no effect on AP prolactin release. These results indicate that the hypothalamus contains a factor(s) which inhibits synthesis and release of prolactin by the rat AP in vitro, and this factor(s) is not any of the recognized neurohumors in the hypothalamus.

Influence of Diet on in Vitro and in Vivo Rates of Fatty Acid Synthesis in Coho Salmon [Oncorhynchus Kisutch (Walbaum)]

1977 ◽  
Vol 107 (9) ◽  
pp. 1677-1682 ◽  
Author(s):  
Huangsheng Lin ◽  
Dale R. Romsos ◽  
Peter I. Tack ◽  
Gilbert A. Leveille
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Acid Synthesis

scholarly journals Lunar cycles of coho salmon, Oncorhynchus kisutch. II. Scale amino acid uptake, nucleic acids, metabolic reserves and plasma thyroid hormones

1987 ◽  
Vol 129 (1) ◽  
pp. 179-189
Author(s):  
K. J. Farbridge ◽  
J. F. Leatherland
Keyword(s):  
Coho Salmon ◽  
Growth Parameters ◽  
Oncorhynchus Kisutch ◽  
Amino Acid Uptake ◽  
Lunar Cycle ◽  
Acid Uptake ◽  
Glycine Uptake ◽  
Lunar Cycles ◽  
Cyclical Pattern

[14C]glycine uptake by scales in vitro was measured in coho salmon (Oncorhynchus kisutch Walbaum) smolts at different times during several semi-lunar cycles. There was a clear cyclical pattern of glycine uptake during the semi-lunar period. Evidence for semi-lunar cycles of liver and muscle RNA:DNA ratios, carcass water content, haematocrit, and plasma triglyceride, glucose and cholesterol levels was also found in coho salmon parrs. Plasma L-thyroxine (T4) levels exhibited a cyclical pattern during the semi-lunar cycle in parrs sampled in March when plasma T4 levels tended to be low, but no such pattern was seen in parrs sampled in January when the plasma T4 levels were relatively high (1.39-1.88 micrograms dl-1 in January compared with 0.38-0.83 micrograms dl-1 in March). There were no apparent semi-lunar cycles in liver mass:body mass ratios and plasma triiodo-L-thyronine (T3) levels. Changes in growth parameters (nucleic acid levels and glycine uptake by scales) and the content of nutrient reserves are discussed in relation to the semi-lunar patterns of growth in length, growth in mass, and food intake in this species.

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