Search results for "N-acetyltransferase"
showing 5 items of 35 documents
miR-15a-3p Protects Against Isoniazid-Induced Liver Injury via Suppressing N-Acetyltransferase 2 Expression
2021
Isoniazid (INH), an effective first-line drug for tuberculosis treatment, has been reported to be associated with hepatotoxicity for decades, but the underlying mechanisms are poorly understood. N-acetyltransferase 2 (NAT2) is a Phase II enzyme that specifically catalyzes the acetylation of INH, and NAT2 expression/activity play pivotal roles in INH metabolism, drug efficacy, and toxicity. In this study, we systematically investigated the regulatory roles of microRNA (miRNA) in NAT2 expression and INH-induced liver injury via a series of in silico, in vitro, and in vivo analyses. Four mature miRNAs, including hsa-miR-15a-3p, hsa-miR-628-5p, hsa-miR-1262, and hsa-miR-3132, were predicted to …
Effects of LHRH, progesterone, estradiol-17 ? and dexamethasone in vitro on pineal synaptic ribbons and serotonin N-acetyltransferase activity in die…
1991
Pineal glands of regularly cycling Sprague Dawley rats (180-220 g) killed on the diestrous morning (between 0900-1000 h) were incubated in appropriate media for six hours with LHRH (8.5 microM), progesterone (3.2 microM), estradiol-17 beta (370 nM) or dexamethasone (250 nM). Pineals incubated in hormone-free medium and unincubated glands served as controls. Six rats were used in each group. After incubation the glands were divided into two parts. One part was used to estimate serotonin N-acetyltransferase (NAT) activity. The other part was processed for electron microscopy to quantify synaptic ribbons (SR). The SR numbers were computed to 20,000 microns 2 area of pineal tissue. The number a…
Arylalkylamine N-acetyltransferase gene expression in retina and pineal gland of rats under various photoperiods
2004
Abstract The present study examines how the circadian oscillators in the retina and the suprachiasmatic nucleus (SCN) respond to changes in photoperiod. ArylalkylamineN-acetyltransferase (aa-nat) gene expression studied by quantitative RT-PCR revealed that in adult Sprague–Dawley rats kept under different light–dark (LD) cycles for two weeks the temporal pattern of AA-NAT mRNA expression was identical in retina and pineal gland. In both tissues, the time span between the onset of darkness and the nocturnal rise in AA-NAT mRNA expression was 3 h under LD 20:4, 6 h under LD 12:12, and 15 h under LD 4:20. As aa-nat expression in the pineal gland is regulated by the circadian oscillator in SCN,…
Circadian rhythm in NO synthase I transcript expression and its photoperiodic regulation in the rat pineal gland.
2001
The photoneural regulation of nitric oxide synthase type I (NOS I) expression in the rat pineal was investigated using semiquantitative RT-PCR. NOS I transcript expression exhibited a daily rhythm with peak values during the night hours. The daily rhythm in NOS I transcript expression persisted under constant dark conditions and was abolished under constant light conditions. The extent of nocturnal NOS I expression was found to be dependent on the photoperiod. It was attenuated under 20 h light and 4 h dark (L:D 20:4) compared with 12 h light and 12 h dark (L:D 12:12). The present findings indicate that, in the rat pineal, NOS I transcript expression exhibits a true circadian rhythm. Furthe…
The phototransduction cascade in the isolated chick pineal gland revisited.
2003
It is well established that the isolated chick pineal gland is directly light sensitive and that melatonin synthesis of the gland can be inhibited by exposing the gland to light during scotophase. Since not all the steps of the phototransduction cascade have been clarified to the same extent as in the retina, we have treated isolated chick pineal glands with 90 min of light during scotophase and with drugs that affect key-components of vertebrate phototransduction, i.e., cyclic guanosine monophosphate (cGMP) phosphodiesterase 6 (PDE6), cGMP levels and cGMP-gated calcium channels. The endpoint measured was the activity of the rate-limiting enzyme of melatonin synthesis, arylalkylamine N-acet…