HOMOLOGOUS RADIOIMMUNOASSAY FOR CANINE PROLACTIN

1977 ◽  
Vol 85 (4) ◽  
pp. 736-743 ◽  
Author(s):  
P. J. Knight ◽  
J. M. Hamilton ◽  
C. G. Scanes

ABSTRACT A homologous double antibody radioimmunoassay has been developed for canine prolactin. Purified canine prolactin was iodinated by lactoperoxidase/H2O2 to an average of 101 ± 10.1 μCi/μg. Antiserum was used at a final dilution of 1:80 000 and at this concentration bound approximately 20% of the added tracer in the absence of competing unlabelled prolactin. Partial cross-reaction was observed with ovine and bovine prolactin but there was no cross-reaction with a highly purified canine growth hormone preparation. Dilutions of pregnant and lactating bitch sera were parallel to the purified canine prolactin standard curve. Mean prolactin levels in normal male and anoestrous females were 8.8 ± 0.8 and 12.6 ± 2.6 ng/ml, respectively. Thyrotrophin-releasing hormone (TRH) induced a consistent elevation in prolactin levels 15–30 min after intravenous injection.

1976 ◽  
Vol 81 (1) ◽  
pp. 1-8 ◽  
Author(s):  
K. Maeda ◽  
Y. Kato ◽  
N. Yamaguchi ◽  
K. Chihara ◽  
S. Ohgo ◽  
...  

ABSTRACT The effect of thyrotrophin-releasing hormone (TRH) or luteinizing hormone-releasing hormone (LH-RH) on plasma levels of growth hormone (GH), prolactin (PRL), thyrotrophin (TSH), and luteinizing hormone (LH), were studied in patients with anorexia nervosa. The basal plasma GH levels were elevated in 6 of 11 patients studied. Intravenous injection of synthetic TRH (500 μg) significantly raised the plasma GH levels in 9 of 11 patients. The peak values of plasma GH after TRH ranged from 6.0 to 31.5 ng/ml. Plasma GH concentrations also increased following the administration of synthetic LH-RH (100μg) in 1 of 7 patients. The intravenous injection of saline solution caused no significant change in plasma GH in these patients. The plasma LH responses to LH-RH were significantly blunted in all patients, whereas the plasma PRL and TSH responses to TRH were almost normal in the patients examined. These results suggest that the hypothalamo-pituitary function regulating GH and LH secretion is altered in patients with anorexia nervosa.


1999 ◽  
Vol 14 (11) ◽  
pp. 2704-2708 ◽  
Author(s):  
Th. Kaltsas ◽  
N. Pontikides ◽  
G.E. Krassas ◽  
K. Seferiadis ◽  
D. Lolis ◽  
...  

1977 ◽  
Vol 84 (1) ◽  
pp. 23-35 ◽  
Author(s):  
E. Rutlin ◽  
E. Haug ◽  
P. A. Torjesen

ABSTRACT The serum levels of thyrotrophin (TSH), prolactin (PRL) and growth hormone (GH) and the response of these hormones to 500 μg thyrotrophin-releasing hormone (TRH) iv were studied in menstruating women. in post-menopausal women before and after 2 mg oestradiol valerate for 5 consecutive days, and in men on long term oestrogen treatment. Oestrogen treatment had no effect on basal serum TSH levels, which were within the normal range in all groups. The TSH response to TRH was not different in menstruating and post-menopausal women and was not changed in the latter group after oestrogen treatment. In men treated chronically with oestrogens, the TSH response to TRH was similar to that found in normal male subjects. There was no difference in basal levels of serum PRL between males and menstruating females. In the post-menopausal women, however, basal levels of serum PRL was significantly decreased, but rose during oestrogen treatment to serum levels normally found in menstruating women. In the oestrogen treated males basal serum PRL levels were significantly higher than in untreated men. The PRL response to TRH was significantly greater in females than in males, but in the oestrogen treated males the PRL response to TRH was greatly increased and almost of the same magnitude as the response in females. There was no difference in PRL response between menstruating and post-menopausal women, and oestrogen treatment of the latter group had no significant effect on the PRL response. Basal levels of serum GH did not differ between the groups. In the group of 9 post-menopausal women one subject showed a small GH response to TRH prior to oestrogen treatment, while 7 subjects showed GH responses to TRH after oestrogen treatment. In the group of 5 chronically oestrogen treated men, 2 subjects had increased serum levels of GH after TRH. Thus our data show that oestrogen administration may induce PRL release in human subjects, while oestrogens seem to play a far less important role in the regulation of GH and TSH secretion.


1982 ◽  
Vol 99 (3) ◽  
pp. 344-351 ◽  
Author(s):  
Abraham Martinez-Campos ◽  
Paolo Giovannini ◽  
Antonello Novelli ◽  
Daniela Cocchi ◽  
Tommaso Caraceni ◽  
...  

Abstract. The thyrotrophin (TSH) and prolactin (Prl)-releasing effects of TSH-releasing hormone (TRH) were investigated in 20 subjects with Parkinson's disease (PD), unmedicated, on chronic treatment with a combination levodopa-benserazide (Madopar) or levodopa-carbidopa (Sinemet) or withdrawn from therapy. Administration of TRH (200 μg iv) induced in unmedicated patients TSH and Prl responses significantly lower than those of sex-and age-matched controls. In patients on Madopar therapy the TSH and Prl responses to TRH were greater than in unmedicated patients and comparable to those of controls, while in patients on Sinemet therapy the pituitary responses were undistinguishable from those of unmedicated subjects. Withdrawal of Madopar therapy resulted in a marked diminution of the TSH response but did not affect the Prl response to TRH. Withdrawal of Sinemet therapy did not alter the TSH and Prl responses to TRH. Concomitant evaluation of growth hormone (GH) levels, in none of the subjects evidenced non-specific changes in plasma GH following TRH. Since TSH and Prl responses to TRH are inhibited by an enhancement of the dopaminergic tone, it would appear that the latter is preserved in the tuberoinfundibular system of unmedicated subjects and subjects on chronic Sinemet therapy, but is defective in subjects on chronic Madopar therapy.


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