Changes in adenylate cyclase activity in rat pituitary after TRH and T3 injection in vivo

1980 ◽  
Vol 95 (2) ◽  
pp. 166-171 ◽  
Author(s):  
Hana Brozmanová ◽  
Pavel Langer ◽  
Jan Knopp ◽  
Ondrej Földes
Keyword(s):  
Adenylate Cyclase ◽  
Anterior Pituitary ◽  
Peak Level ◽  
Male Rats ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Rat Pituitary ◽  
Increased Activity ◽  
Peak Value

Abstract. Increased activity of adenylate cyclase in whole anterior pituitary was repeatedly found in groups of 3–6 adult male rats 5 min after iv injection of 10, 100 and 200 nmol of TRH kg−1. After the administration of 100 nmol TRH kg−1 the activity of adenylate cyclase was significantly increased at 2, 5, 10 and 30 min with a peak level at 5 min, while at 60 min the values did not differ from controls. The level of TSH in serum was significantly increased in all TRH injected groups with a peak value at 10 min, while no dose-response relationship was found at 5 min. Finally, the activity of adenylate cyclase was significantly decreased in animals injected with 20 nmol of l-triiodothyronine kg−1 180 min before sacrifice, the decrease being not overcome by 100 nmol TRH kg−1 injected 5 min before sacrifice.

scholarly journals Factors that Determine the in vivo Dose-Response Relationship for Stable Chromosome Aberrations in A-Bomb Survivors

1992 ◽  
Vol 33 (SUPPLEMENT) ◽  
pp. 206-214 ◽  
Author(s):  
AKIO A. AWA ◽  
MIMAKO NAKANO ◽  
KAZUO OHTAKI ◽  
YOSHIAKI KODAMA ◽  
JOE LUCAS ◽  
...  
Keyword(s):  
Dose Response ◽  
Chromosome Aberrations ◽  
Response Relationship ◽  
Dose Response Relationship

scholarly journals Oral Artesunate Dose-Response Relationship in Acute Falciparum Malaria

2002 ◽  
Vol 46 (3) ◽  
pp. 778-782 ◽  
Author(s):  
Brian J. Angus ◽  
Itaporn Thaiaporn ◽  
Kenechanh Chanthapadith ◽  
Yupin Suputtamongkol ◽  
Nicholas J. White
Keyword(s):  
Falciparum Malaria ◽  
Dose Response ◽  
Parasite Clearance ◽  
Multidrug Resistant ◽  
Maximum Effect ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
To Receive ◽  
The Relationship

ABSTRACT The combination of an oral artemisinin derivative (usually artesunate) and mefloquine has become standard treatment for multidrug-resistant falciparum malaria in several parts of Southeast Asia. The doses of artesunate used in monotherapy and combination treatment have largely been derived empirically. In order to characterize the in vivo dose-response relationship for artesunate and thus rationalize dosing, 47 adult patients with acute uncomplicated falciparum malaria and parasitemia ≥1% were randomized to receive a single oral dose of artesunate varying between 0 and 250 mg together with a curative dose of oral mefloquine. Acceleration of parasite clearance was used as the pharmacodynamic variable. An inhibitory sigmoidal maximum effect (E max) pharmacodynamic model typical of a dose-response curve was fitted to the relationship between dose and shortening of parasite clearance time (PCT). The E max was estimated as 28.6 oral h, and the 50% effective concentration was 1.6 mg/kg of body weight. These results imply that there is no reduction in PCTs with the use of single doses of artesunate higher than 2 mg/kg, and this therefore reflects the average lower limit of the maximally effective dose.

BIOSYNTHESIS OF GONADOTROPHINS BY RAT PITUITARIES IN VITRO

1975 ◽  
Vol 66 (3) ◽  
pp. 369-374 ◽  
Author(s):  
MRIDULA CHOWDHURY ◽  
EMIL STEINBERGER
Keyword(s):  
Comparative Study ◽  
Anterior Pituitary ◽  
Male Rats ◽  
Leucine Incorporation ◽  
Experimental Conditions ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Endogenous Proteases ◽  
Pituitary Homogenate

SUMMARY A method has been developed for studying biosynthesis of FSH in the rat pituitary in vitro. Anterior pituitary glands were incubated with [3H]leucine; a specific and sensitive immunoprecipitation technique was used to isolate FSH from the pituitary homogenate. Total FSH content of the samples was measured by a double-antibody radioimmunoassay technique. Using this technique, a comparative study of LH and FSH synthesis in the same pituitary of adult male rats incubated for various intervals (0·5–6 h) was done. Increased incorporation of [3H]leucine into both LH and FSH with time was noted. The rate and amount of [3H]leucine incorporation into FSH was found to be higher than that into LH, indicating that either the rate of FSH synthesis is higher than that of LH or FSH has more leucine residues than LH. Greater susceptibility of LH to degradation by endogenous proteases during dialysis may also reflect less incorporation of [3H]leucine into LH. This method provides a reliable tool for evaluating FSH synthesis under various experimental conditions.

THE EFFECTS OF AGE AND OESTRONE TREATMENT ON DNA POLYMERASE ACTIVITY IN ANTERIOR PITUITARY GLANDS OF MALE RATS

1973 ◽  
Vol 59 (1) ◽  
pp. 107-119 ◽  
Author(s):  
ANDREA MASTRO ◽  
W. C. HYMER
Keyword(s):  
Dna Polymerase ◽  
Anterior Pituitary ◽  
Reaction Medium ◽  
Polymerase Activity ◽  
Male Rats ◽  
Synthetic Activity ◽  
Cytoplasmic Fraction ◽  
Isolated Nuclei ◽  
Pituitary Glands

SUMMARY DNA polymerase activity was found in the cytoplasmic fraction and in isolated nuclei from anterior pituitary glands of male rats. The enzyme activity was assayed by measuring the incorporation of [3H]dTTP into DNA in a medium containing Tris-HCl buffer (pH 8·5), the four deoxyribonucleoside triphosphates, Mg2 +, ATP and activated calf thymus DNA. The DNA polymerase activity decreased with age in glands from animals aged 25 days to over a year but increased after oestrone treatment in vivo. These changes in activity, more pronounced in the cytoplasmic fraction than in the isolated nuclei, were similar to changes in DNA synthesis measured in anterior pituitary glands under the same physiological conditions. Isolated nuclei also retained endogenous DNA synthetic activity in the absence of added template. Addition of a cytoplasmic fraction to the reaction medium stimulated activity by as much as 1·9-fold but the degree of stimulation was the same whether the cytoplasm was from young, old or oestrone-treated animals.

scholarly journals Critical Evaluation of Two Commercial Biocontrol Agents for Their Efficacy against B. cinerea under In Vitro and In Vivo Conditions in Relation to Different Abiotic Factors

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1868
Author(s):  
Gurkan Tut ◽  
Naresh Magan ◽  
Philp Brain ◽  
Xiangming Xu
Keyword(s):  
Dose Response ◽  
Abiotic Factors ◽  
Critical Evaluation ◽  
Leaf Disc ◽  
Biocontrol Agents ◽  
In Vivo Studies ◽  
Response Relationship ◽  
Dose Response Relationship

The study evaluated the dose–response relationship of two commercial microbial biocontrol agents, Bacillus subtilis and Gliocladium catenulatum, against Botrytis cinerea both in vitro and in vivo. Inoculum doses, formulation, temperature and foliar leaf part all affected the control achieved by the two BCAs. In vitro competition assays on modified PDA plates tested a range of BCA doses (log10 3–10 CFUs or spores/droplet) at 4, 10 and 20 °C on the development of B. cinerea colonies. The dose–response relationship was influenced by both the BCA formulation and temperature. In vivo studies on lettuce plants in semi-commercial greenhouses examined the BCA dose (log10 5–9 CFUs or spores/mL) for controlling B. cinerea with a high inoculum (log10 6 spores/mL). Leaf disc assays showed that the dose–response relationship was influenced by the leaf parts sampled. These results suggest that the dose–response relationship between a BCA and specific pathogen will be significantly influenced by environmental conditions, formulation and plant phyllosplane tissue.

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