Kinetics of steroid responsiveness to hCG during chronic inhibition of testicular function by GnRH analogue

1984 ◽  
Vol 107 (4) ◽  
pp. 544-549
Author(s):  
Enzo Vicari ◽  
Alessandro Mongioi ◽  
Antonia Aliffi ◽  
Salvatore Gulizia ◽  
Rosario D'Agata
Keyword(s):  
Biosynthetic Pathway ◽  
Serum Testosterone ◽  
Gnrh Analogue ◽  
Testicular Function ◽  
Term Administration ◽  
Significant Release ◽  
Prepubertal Boys ◽  
Steroid Responsiveness ◽  
Kinetics Of

Abstract. The effect of daily injections of D-Ser-(TBU)6-LRH-EA10 (GnRH analogue (GnRH-A) 100 μg sc) on serum testosterone (T),17α-hydroxyprogesterone (17OHP) and oestradiol-17β (E2) was studied in 4 men. During GnRH-A therapy T, 17OHP and E2 were markedly decreased by the end of the second month. Continuous long-term administration of GnRh-A inhibited testicular function. To test whether the biosynthetic pathway was affected by the regimen, a bolus of 2000 U hCG was given to each subject after 10 months of therapy. Evaluation of the kinetics of steroid responsiveness showed a significant release of T in response to the trophic stimulus, with little or nor elevation of serum 17OHP and E2. The response seen in these treated men appeared similar to that found in hypogonadotrophic men and prepubertal boys.

KINETICS OF DISTRIBUTION OF RADIOACTIVE PERCHLORATE IN RAT AND GUINEA-PIG THYROID GLANDS

1970 ◽  
Vol 47 (2) ◽  
pp. 207-218 ◽  
Author(s):  
SIEN YAO CHOW ◽  
D. M. WOODBURY
Keyword(s):  
Interstitial Fluid ◽  
Apical Membrane ◽  
Follicular Cells ◽  
Step Process ◽  
Perchlorate Ion ◽  
Thyroid Glands ◽  
Term Administration ◽  
Apical Membranes ◽  
Kinetics Of

SUMMARY The thyroidal uptake of 36ClO4− and the effect of stable perchlorate ion and functional state of the thyroid, such as after long-term administration of propylthiouracil (PTU) or after hypophysectomy, on the uptake of 36ClO4− were studied in rats and guinea-pigs. Based on the analysis of uptake curves, radioactive inulin and sulphate spaces, and histological measurements of compartmental sizes of the thyroid, the relative concentrations of 36ClO4− in the various compartments were calculated and compared with those of 36Cl-. The passage of 36ClO4− and 36Cl− across both the basal and the apical membranes of the follicular cells in the different conditions were analysed. The results suggest that 36ClO4− is concentrated in the lumen of the thyroid by a two-step process. It is actively transported across the basal cell membrane from the interstitial fluid into follicular cells, and is further concentrated in passage across the apical membrane into the lumen. The evidence suggests that the latter process is also an active one.

scholarly journals Peripheral serotonin and tryptophan levels in rats under progesterone long-term administration

2016 ◽  
Vol 20 (1) ◽  
pp. 5-7
Author(s):  
A. Aleksandrov ◽  
V. Konopelniuk ◽  
L. Ostapchenko
Keyword(s):  
Blood Serum ◽  
Biosynthetic Pathway ◽  
Control Group ◽  
Content Increase ◽  
Serotonin Content ◽  
Term Administration

Tryptophan and serotonin levels in duodenum mucosa and blood serum of rats under progesterone long-term administration have been determined. The studies show that tryptophan and the serotonin content increase in rats under progesterone long-term administration compared with control group of rats. Obtained data give evidence that biosynthetic pathway of serotonin, particularly, content of serotonin, is involved in the obesity development induced by progesterone long-term administration.

Cell kinetics of mucosal atrophy in rat stomach induced by long-term administration of ammonia

1993 ◽  
Vol 104 (3) ◽  
pp. 796-801 ◽  
Author(s):  
Masahiko Tsujii ◽  
Sunao Kawano ◽  
Shingo Tsuji ◽  
Toshifumi Ito ◽  
Kouichi Nagano ◽  
...  
Keyword(s):  
Cell Kinetics ◽  
Rat Stomach ◽  
Mucosal Atrophy ◽  
Term Administration ◽  
Kinetics Of

Effect of Long-term Administration of Cordycepin from Cordyceps militaris on Testicular Function in Middle-aged Rats

Planta Medica ◽  
2012 ◽  
Vol 78 (15) ◽  
pp. 1620-1625 ◽  
Author(s):  
Sang-Hyun Sohn ◽  
Su-Chan Lee ◽  
Seock-Yeon Hwang ◽  
Sung-Won Kim ◽  
Il-Woung Kim ◽  
...  
Keyword(s):  
Cordyceps Militaris ◽  
Testicular Function ◽  
Aged Rats ◽  
Middle Aged ◽  
Term Administration

Failure of GnRH analogue to inhibit serum concentrations of testosterone and 17α-hydroxyprogesterone in hCG-substituted hypogonadotropic hypogonadism

1986 ◽  
Vol 113 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Enzo Vicari ◽  
Alessandro Mongioi ◽  
Domenico Recupero ◽  
Francesca Coniglione ◽  
Maria Macchi ◽  
...  
Keyword(s):  
Hypogonadotropic Hypogonadism ◽  
Serum Testosterone ◽  
Gonadotropin Releasing Hormone ◽  
Gnrh Analogue ◽  
Testicular Function ◽  
Androgen Deficiency ◽  
Serum Concentrations ◽  
Experimental Conditions ◽  
Similar Treatment ◽  
Hcg Therapy

Abstract. Gonadotropin-releasing hormone analogues (GnRH-A) induce inhibition of testicular function and reduction of serum testosterone (T) in man, but the mechanism involved is still debatable. To elucidate it we studied six patients with hypogonadotropic hypogonadism (HH) in chronic substitution with hCG for correction of androgen deficiency symptoms, and evaluated the effect of addition of GnRH-A to the hCG therapy on plasma levels of T and 17α-hydroxyprogesterone (17 OHP). All patients were treated with 1000 U of hCG im every 3rd day for 24 weeks. After 8 weeks of this regimen, GnRH-A, Buserelin (D-Ser-TBU-EA-LHRH), 200 μg per day sc, was added and given for 8 weeks. After cessation of analogue administration patients were followed for 8 further weeks. The levels of the two steroids did not differ markedly in the pre- and post-GnRH-A period. GnRH-A given for two months did not lower T or 17 OHP levels as in eugonadal men after similar treatment. The median T concentrations during GnRH-A tended to be increased, with plasma values higher (P < 0.025) than the peak values observed during hCG alone. Since administration of Buserelin did not inhibit hCG-sustained steroid levels in these HH patients, it is conceivable that GnRH-A may have lacked a direct inhibitory gonadal effect in such experimental conditions.

The efficacy and safety of long-term administration of alpha-interferon and lamivudine in patients with chronic hepatitits B

2001 ◽  
Vol 120 (5) ◽  
pp. A572-A572
Author(s):  
F JABOLI ◽  
E RODA ◽  
C FABBRI ◽  
S MARCHETTO ◽  
F FERRARA ◽  
...  
Keyword(s):  
Alpha Interferon ◽  
Efficacy And Safety ◽  
Term Administration

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

STUDIES IN THE SUPPOSED GOITROGENOUS EFFECT OF TAP WATER IN HELSINKI

1960 ◽  
Vol XXXIII (IV) ◽  
pp. 630-636
Author(s):  
F.-E. Krusius ◽  
P. Peltola
Keyword(s):  
Tap Water ◽  
Physiological Saline ◽  
Normal Weight ◽  
The Body ◽  
Iodine Uptake ◽  
Redistilled Water ◽  
Detectable Difference ◽  
Term Administration ◽  
Long Term Experiment

ABSTRACT The study reported here was performed in order to examine the tap water of Helsinki for its alleged goitrogenous effect. In a short-term, 24-hour experiment with rats, kept on an iodine-poor diet, we noticed no inhibition of the 4-hour 131I uptake, as compared with that of animals receiving physiological saline instead of tap water. Two similar groups of rats receiving 1 and 2 mg of mercazole in redistilled water showed a distinct blockage of the 4-hour uptake, which proved the effect of this substance. In a long-term experiment of 5 weeks' duration there was no detectable difference in the body weight, thyroid weight and the 4-hour 131I uptake when the rats receiving tap water or distilled water to which 0.45 per cent of sodium chloride was added were compared with each other. Replacement of tap water by a 10 mg per cent solution of mercazole in redistilled water enlarged the thyroid to double its normal weight and increased the 131I uptake to approximately five times that of the controls. Thus our experiments failed to demonstrate any goitrogenous effect in the tap water of Helsinki. Changes similar to those produced by a long-term administration of mercazole, i. e. an enlargement of the thyroid and an increased thyroidal iodine uptake, have been shown to be due to milk collected from goitrous areas. The observations here reported confirm the importance of milk in the genesis of the goitre endemia of Helsinki. Attention is further called to the fact that a thyroidal enlargement combined with an increased thyroidal iodine uptake cannot always be taken as a sign of iodine deficiency because similar changes may be produced by the administration of goitrogens.

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