Maturation of renal and hepatic monodeiodination of thyroxine to triiodothyronine and post-natal changes of serum thyroid hormones in young rats

1982 ◽  
Vol 99 (4) ◽  
pp. 540-545 ◽  
Author(s):  
Yukichi Suzuki ◽  
Kyoko Kita ◽  
Yasuko Uchigata ◽  
Ikuro Takata ◽  
Tamotu Sato
Keyword(s):  
Neonatal Period ◽  
Physiological Role ◽  
Maximal Activity ◽  
Adult Rats ◽  
Young Rats ◽  
Old Rats ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels ◽  
Serum Thyroid Hormones ◽  
Low Activity

Abstract. Maturational changes of renal and hepatic 5′-monodeiodination of thyroxine (T4) and post-natal changes of serum thyroid hormone levels were investigated in young rats under 35 days of age. Renal T3 generation in the 1-day-old rats was low, rose progressively to a level of more than 200% of the adult rats on days 21 and 28 and declined thereafter. In contrast, hepatic T3 generation increased from an initial low activity to a plateau after 7 days of age, which was 1½ times higher than that of adult rats. Because of the extremely low value of serum T4 in the neonatal period, T3/T4 and rT3/T4 ratios were elevated on day 7. The ratio of rT3/T4 decreased gradually and became stable after 21 days of age, while the T3/T4 ratio increased reciprocally to a peak on days 21 and 28, corresponding to the period of maximal activity of renal T4 monodeiodination. These results indicate that in addition to elevated hepatic T4 monodeiodination, renal conversion of T4 to T3 may play a significant physiological role during the period of enhanced T3 requirement for maturation.

scholarly journals Relative contribution of cysteine and methionine to glutathione content and thyroid hormone levels in the rat

1987 ◽  
Vol 58 (1) ◽  
pp. 105-111 ◽  
Author(s):  
C. Suberville ◽  
P. Higueret ◽  
D. Taruoura ◽  
H. Garcin ◽  
D. Higueret
Keyword(s):  
Thyroid Hormone ◽  
Pisum Sativum ◽  
Thyroid Hormones ◽  
Reduced Glutathione ◽  
Pea Protein ◽  
Relative Contribution ◽  
Methionine Supplementation ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels ◽  
Serum Thyroid Hormones

1. For a period of 24 d rats were given diets containing either casein or pea (Pisum sativum) protein at two different concentrations (180 and 120 g/kg) without or with cysteine or cysteine + methionine supplementation.2. The effects of these diets on levels of blood and liver reduced glutathione (GSH) and serum thyroid hormones were studied.3. When compared with the 180 g casein/kg diet, the 120 g casein/kg diet decreased liver GSH and serum thyroid hormone concentrations. These changes were related to dietary cysteine supply since supplementation induced an increase in these variables.4. When compared with 180 g pea protein/kg diet, the 120 g pea protein/kg diet decreased liver GSH and serum thyroid hormone concentrations. These changes could not be corrected by cysteine or cysteine + methionine supplementation.

Differential adrenergic regulation of rat pineal cyclic AMP production and N-acetyltransferase activity during postnatal development: involvement of G alpha s and G alpha i1-2 proteins

1997 ◽  
Vol 155 (2) ◽  
pp. 305-312
Author(s):  
A Harmouch ◽  
JM Guerrero ◽  
D Pozo ◽  
M Rafii-el-Idrissi ◽  
RJ Reiter ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Postnatal Development ◽  
Adrenergic Receptors ◽  
Beta Adrenergic Receptors ◽  
Adult Rats ◽  
Beta Adrenergic ◽  
Young Rats ◽  
Old Rats ◽  
Gs Alpha ◽  
Rat Pineal Gland

We have studied why rat pineal N-acetyltransferase (NAT) activity is relatively insensitive to isoproterenol in young rats when compared with adult rats. We report that activation by isoproterenol of pineal cyclic AMP production and NAT activity is higher in adult than in 2-week-old rats. However, the effect of dibutyryl cyclic AMP, which enters the pinealocyte and duplicates the effect of cyclic AMP, on NAT activity was similar at both ages. Moreover, we found that both alpha- and beta-adrenergic receptors are highly specific at both ages, since the binding of the specific radioligands used to their receptors could be displaced only by their corresponding agonists and antagonists. However, we observed differences between pineals from young and adult rats when several families of the alpha subunit of G-proteins were studied in cell membranes. ADP-ribosylation and immunoblot studies have shown clear differences in both 42 and 45 kDa forms of the Gs alpha Both forms exhibit low values in pineals from 2-week-old animals when compared with 6-week-old. We also show that the later appearance of both Gs alpha forms is roughly similar to the potent activation of cyclic AMP production and NAT activity in adult rats when compared with young rats. In conclusion, the results presented suggest that the relative lack of sensitivity of rat pineal gland to beta-adrenergic receptor agonists early in the postnatal development may be explained by the low levels of membrane Gs alpha, rather than postreceptor-mediated mechanisms or changes in the characteristics of the beta-adrenergic receptors on the pinealocyte membrane.

scholarly journals Decoding Aging: Understanding the Complex Relationship among Aging, Free Radicals, and GSH

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
María E. López-Navarro ◽  
Mariana Jarquín-Martínez ◽  
Luis A. Sánchez-Labastida ◽  
Daniel Ramírez-Rosales ◽  
Marycarmen Godínez-Victoria ◽  
...  
Keyword(s):  
Free Radicals ◽  
Ex Vivo ◽  
Redox Homeostasis ◽  
Adult Rats ◽  
Paramagnetic Resonance ◽  
Young Rats ◽  
Male Wistar Rats ◽  
Michael Type Addition ◽  
Old Rats ◽  
In Cells

N-aryl maleimides can undergo a 1,4-Michael-type addition reaction with reduced glutathione (GSH), leading to a decreased concentration of GSH and an increased concentration of free radicals (FRs) in cells. GSH is a critical scavenging molecule responsible for protecting cells from oxidation and for maintaining redox homeostasis. N-aryl maleimides disturb redox homeostasis in cells because they scavenge thiol-containing molecules, especially GSH. This study aimed at measuring the concentrations of GSH and FRs by electronic paramagnetic resonance (EPR), in the brain and liver tissue of male Wistar rats (ex vivo) at different ages and after treatment with 3,5-dimaleimylbenzoic acid (3,5-DMB). Our results showed a relationship between age and the concentrations of GSH and FRs in cells. In young rats, the concentration of GSH was higher than in old rats, while the concentration of FRs was higher in adult rats than in young rats, suggesting an inverse relationship between GSH and FRs. On the other hand, the reaction of 3,5-DMB (an electrophilic maleimide) with cellular GSH increased the FR content. The results of this study contribute to the awareness that the process of aging implies not only a loss of tissue function but also essential changes in the molecular contents of cells, especially the concentrations of FRs and GSH.

The production of antibodies by young rats

1957 ◽  
Vol 147 (926) ◽  
pp. 140-144 ◽  
Keyword(s):  
Active Immunization ◽  
Protein Fractions ◽  
Antibody Activity ◽  
Adult Rats ◽  
Marked Rise ◽  
Suckling Rats ◽  
Young Rats ◽  
Salmonella Pullorum ◽  
Old Rats

Suckling rats can produce specific agglutinins to Salmonella pullorum during the period when normally γ -globulin is being absorbed from the milk. This production of antibody is as efficient in rats prevented from suckling their mothers as it is in litter-mates suckling normally. The titres of young rats passively immunized by suckling mothers hyperimmune to Salm . pullorum show a decline between 18 and 24 days of age paralleling the decline of more than 80% in the concentration of serum γ -globulin which is known to take place over this period. Yet the titres of actively immunized young rats rise over the same period. These results suggest that the antibody produced by the active immunization is concentrated in the β -globulin, since this alone shows a marked rise during the period. It is known that the antibody activity in adult rats hyperimmunized against Salm . pullorum is concentrated in the γ -globulin. The results of the examination of electrophoretically separated protein fractions of the sera from actively immunized 24-day-old rats support this conclusion, as the bulk of the antibody was found to be present in those fractions which contained β -globulin. Evidence of the production of γ -globulin by the suckling rat was also obtained, however, because of the presence of a small but significant amount of antibody in a fraction containing only γ -globulin.

Association of insulin-like growth factor mRNA expressions with muscle regeneration in young, adult, and old rats

1997 ◽  
Vol 273 (1) ◽  
pp. R353-R358 ◽  
Author(s):  
D. R. Marsh ◽  
D. S. Criswell ◽  
M. T. Hamilton ◽  
F. W. Booth
Keyword(s):  
Young Adult ◽  
Growth Factor ◽  
Mrna Expression ◽  
Tibialis Anterior ◽  
Tibialis Anterior Muscle ◽  
Insulin Like Growth Factor ◽  
Adult Rats ◽  
Young Rats ◽  
Igf I ◽  
Old Rats

The purpose of this study was to determine whether impaired regeneration of skeletal muscle in old rats can be attributed to diminished expression of insulin-like growth factor (IGF) mRNAs. Fischer 344 male rats aged 2 (young), 12 (adult), and 24 mo (old) were given an injection of the myotoxic anesthetic, bupivacaine, into the left tibialis anterior muscle. Muscle mass and protein concentration recovered to contralateral control values by 28 days in young, but not adult or old rats. The temporal and maximal expressions of IGF-I mRNA were similar during recovery from bupivacaine on days 5 and 10 in young, adult, and old rat muscles. IGF-I mRNA levels were reduced toward control levels in young rats by 15 days, but remained elevated in adult and old rats. IGF-I receptor mRNA in bupivacaine-injected muscle of old rats was elevated significantly higher than injected muscle of young and adult rats at recovery day 5. Five days after bupivacaine injection, IGF-II mRNA was increased 46-fold in young rats but was only increased fourfold in adult rats. Thereafter, IGF-II mRNA expression was similar for young, adult, and old rats at 10 and 15 days of recovery. In summary, we demonstrate that impaired regeneration of the tibialis anterior muscle in adult or old rats after bupivacaine-induced damage is associated with a prolonged elevation of IGF-I mRNA expression and/or diminished initial IGF-II mRNA expression.

Age-associated changes in ammoniagenesis in isolated rat renal tubule segments

1992 ◽  
Vol 262 (4) ◽  
pp. F600-F605
Author(s):  
H. Yamada ◽  
B. Sacktor ◽  
J. Kinsella
Keyword(s):  
Serum Creatinine ◽  
Ammonia Production ◽  
Control Groups ◽  
Adult Rats ◽  
Young Rats ◽  
Blood Ph ◽  
Significant Difference ◽  
Acid Load ◽  
Old Rats ◽  
Convoluted Tubules

We investigated renal ammoniagenesis in isolated nephron segments from control and acidotic senescent and young adult rats. When young (6 mo) and senescent (24 mo) control groups were compared, there was no significant difference in glutamine-dependent ammonia production in any nephron tubule segments. However, ammonia production rates in glomeruli from old rats were significantly greater than the rate from young rats and were correlated with the serum creatinine and blood urea nitrogen (BUN) levels. After giving young and old rats an equivalent acid load (by gavage) of ammonia chloride solutions (6 mo, blood pH 7.34; 24 mo, blood pH 7.07), we measured a significant increase in ammoniagenesis on the S1 and S2 segments of proximal tubules and the distal convoluted tubules from old rats, and no increase in any segment from young rats. When we increased the acid load in young rats to an equivalent severity of acidosis (blood pH 7.07), we found significant increases in ammonia production in the S1, S2, S3, and distal convoluted tubule. With comparable blood pH values, ammoniagenesis in S1, S2, and S3 segments from young rats was about double the values measured in segments from senescent rats. The severity of the acidosis in the 24-mo-old rats was related to serum creatinine and BUN. Our findings show that ammoniagenesis in isolated segments from senescent rats is qualitatively similar to their younger counterparts but that this maximum capacity to generate ammonia is reduced. The change in nephron capacity to synthesize ammonia may be the result of age-associated physiological changes and/or the chronic renal failure exhibited in old rats.

Sensitivity changes to inotropic agents in rabbit atria after chronic experimental diabetes

1988 ◽  
Vol 66 (12) ◽  
pp. 1475-1480 ◽  
Author(s):  
Paul F. Grassby ◽  
John H. McNeill
Keyword(s):  
Thyroid Hormone ◽  
Experimental Diabetes ◽  
Diabetic Rat ◽  
Inotropic Agents ◽  
Adrenergic Stimulation ◽  
Response Curves ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels ◽  
Serum Thyroid Hormones ◽  
Low Serum

The effect of experimental diabetes on the sensitivity of isolated left atrial strips to inotropic agents was investigated in rabbits made diabetic with alloxan. After 4 weeks of diabetes no change in sensitivity was detected in response to isoproterenol or ouabain. In contrast, 15 weeks of diabetes induced a decreased sensitivity to β-adrenergic stimulation, exhibited as a shift to the right in concentration–response curves obtained in response to isoproterenol and noradrenaline. In addition, after 15 weeks of diabetes the inotropic response to ouabain was depressed, and a small decrease in sensitivity was detected in response to forskolin. In contrast, no significant changes in the concentration–response curves obtained from α-adrenergic stimulation by phenylephrine or calcium chloride were detected. Unlike the streptozotocin diabetic rat, which exhibits low serum thyroid hormone levels, no changes in serum thyroid hormones were detected in the alloxan diabetic rabbit. It is suggested that the increased inotropic sensitivity to α-adrenergic agonists observed in the diabetic rat, but not in the rabbit, may be due to low serum thyroid hormone levels. In contrast, the deleterious effects of diabetes on β-adrenergic and ouabain sensitivity occur independently of changes in serum thyroid hormones.

scholarly journals Liver phenylalanine hydroxylase activity in relation to blood concentrations of tyrosine and phenylalanine in the rat

1972 ◽  
Vol 127 (4) ◽  
pp. 675-680 ◽  
Author(s):  
Margaret M. McGee ◽  
Olga Greengard ◽  
W. Eugene Knox
Keyword(s):  
Phenylalanine Hydroxylase ◽  
Quantitative Relationship ◽  
Initial Increase ◽  
Hydroxylase Activity ◽  
Adult Rats ◽  
Blood Concentrations ◽  
Young Rats ◽  
Old Rats ◽  
Phenylalanine Metabolism

The plasma concentration of phenylalanine and tyrosine decreases in normal rats during the first few postnatal days; subsequently, the concentration of phenylalanine remains more or less constant, whereas that of tyrosine exhibits a high peak on day 13. The basal concentrations of the two amino acids were not altered by injections of thyroxine or cortisol, except in 13-day-old rats, when an injection of cortisol decreased the concentration of tyrosine. In young rats (13–15 days old), treatment with cortisol increased the activity of phenylalanine hydroxylase in the liver (measured in vitro) and accelerated the metabolism of administered phenylalanine: the rate constant of the disappearance of phenylalanine from plasma and the initial increase in tyrosine in plasma correlated quantitatively with the activity of phenylalanine hydroxylase in the liver. In adult rats, the inhibition of this enzyme (attested by assay in vitro) by p-chlorophenylalanine resulted in a proportionate decrease in tyrosine formation from an injection of phenylalanine. However, the quantitative relationship between liver phenylalanine hydroxylase activity and phenylalanine metabolism within the group of young rats was different from that observed among adult rats.

scholarly journals Effects of Daily Kelp (Laminaria japonica) Intake on Body Composition, Serum Lipid Levels, and Thyroid Hormone Levels in Healthy Japanese Adults: A Randomized, Double-Blind Study

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 352
Author(s):  
Seiichiro Aoe ◽  
Chiemi Yamanaka ◽  
Hirofumi Ohtoshi ◽  
Fumiko Nakamura ◽  
Suguru Fujiwara
Keyword(s):  
Thyroid Hormone ◽  
Body Fat ◽  
Laminaria Japonica ◽  
Body Fat Percentage ◽  
Fat Percentage ◽  
Double Blind ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels ◽  
Male Subjects ◽  
Japanese Subjects

To investigate whether supplementation with iodine-reduced kelp (Laminaria japonica) powder decreases body fat composition in overweight Japanese subjects, a randomized, double-blind, placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI) ≥25 and <30 kg/m2. Subjects were randomly assigned to consume thirty tablets/d (10 tablets orally, 3 times/d) containing either iodine-reduced kelp powder (test, 6 g kelp powder corresponding to 3 g alginate/d) or kelp-free powder (placebo) for 8 weeks. Anthropometric measurements, blood lipids, and serum thyroid hormone levels were obtained before and after the trial. Body fat percentage was significantly decreased in male subjects from the test group compared with the placebo group. The same tendency was observed for body weight (p = 0.065) and BMI (p = 0.072) in male subjects. No significant changes in anthropometric measurements or visceral fat area were observed in female subjects. Serum thyroid hormone concentrations did not increase after 1.03 mg/d of iodine supplementation through kelp intake. The intake of iodine-reduced kelp powder led to significant and safe reductions in body fat percentage in overweight male subjects. The consumption of kelp high in alginate may contribute to preventing obesity without influencing thyroid function in Japanese subjects with a relatively high intake of iodine from seaweed.

Development of sensitivity to cAMP-inducing hormones in the rat stomach

1984 ◽  
Vol 247 (3) ◽  
pp. G231-G239
Author(s):  
C. Gespach ◽  
Y. Cherel ◽  
G. Rosselin
Keyword(s):  
Biological Activities ◽  
Physiological Role ◽  
H2 Receptor Antagonist ◽  
Adult Rats ◽  
Gastric Glands ◽  
Camp Generation ◽  
Final Maturation ◽  
Noncompetitive Inhibitor ◽  
Regulatory Properties

Development of cAMP responses to secretin, pancreatic glucagon, and histamine was measured in gastric glands of fetal (day 20), postnatal (days 1-30), and adult rats (day 65). cAMP stimulation by these hormones was already detected on day 20 of gestation. cAMP generation showed biphasic variations during the 1st days of life and at the onset of weaning (day 20). Anticipated weaning at day 14 triggered precocious maturation (efficacies) of the cAMP-generating systems sensitive to secretin, glucagon, and histamine without changing the potencies of the hormones. During development, the general characteristics (potency and pharmacological or regulatory properties) of the receptor-cAMP systems studied were comparable with those evidenced in adult rats. At days 5, 20, and 65, vasoactive intestinal peptide and the peptide having N-terminal histidine and C-terminal isoleucine amide (PHI) were about 100 times less potent than secretin (EC50 = 1.5 X 10(-9) M secretin). The histamine action could be blocked by the competitive H2-receptor antagonist cimetidine (70-100% inhibition) as well as by the noncompetitive inhibitor somatostatin (37-62% inhibition). The data indicate that these regulatory hormones (secretin, glucagon(s), histamine, and somatostatin) might have a direct effect on gastric glands and may modulate their biological activities (metabolism, differentiation, proliferation, and exocrine and endocrine secretions) from the neonatal period in rats. The important physiological role of weaning on the final maturation of the cAMP-generating systems in rat gastric glands is underlined.

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