Effects of ethanol on intraovarian nitric oxide production in the prepubertal rat

Abstract

Nitric oxide (NO) has been shown to contribute to ovarian development and function. In non-ovarian tissues NO can be altered by ethanol (ETOH), a drug considered to be a gonadal toxin in men as well as male and female rats. The present study was undertaken to determine if some of the detrimental effects of chronic ETOH exposure on prepubertal ovarian function could be due to ETOH-induced alterations in the intraovarian NO system. Rats were implanted with intragastric cannulae on day 24 and began receiving control or ETOH diets on day 29. All rats were killed on day 34, determined to be in the late juvenile stage of development, and their ovaries and blood were collected. We analyzed the expression of the two constitutive forms of nitric oxide synthase (NOS), i.e. neuronal (n) NOS and endothelial (e) NOS, as well as the inducible (i) form of NOS protein in the ovaries of control and ETOH-treated rats by Western immunoblotting. Results demonstrate that eNOS protein increased markedly (P<0·02; 140 kDa) in ETOH-treated rats compared with controls. ETOH treatment did not alter the protein expression of nNOS (155 kDa) and only slightly increased that of iNOS (130 kDa). We also assessed NOS activity as determined by nitrite accumulation and by the conversion of -[14 C]arginine to -[ 14 C]citrulline. In this regard, the ETOH-treated animals showed an increase in ovarian nitrite generation (P<0·05), as well as an increase in ovarian citrulline formation (P<0·0001), when compared with control animals. Along with the above described ETOH-induced increases in ovarian eNOS and NO activity, the serum levels of estradiol were concomitantly suppressed (P<0·001) in the ETOH-treated rats. These results demonstrate for the first time the ETOH-induced changes in the prepubertal ovarian NO/NOS system, and suggest that these alterations contribute to the detrimental actions of the drug on prepubertal ovarian development and function.

Role of Nitric Oxide in Ethanol‐Induced Up‐Regulation of Muscarinic Acetylcholine Receptors in SH‐SY5Y Cells

“…Furthermore, inhibition of NOS in rats blocked the development of rapid tolerance to the motor-incoordinating effect of ethanol (Khanna et al, 1993(Khanna et al, , 1995 and alleviated the signs of ethanol withdrawal (Uzbay et al, 1997); this suggests that ethanol may act by inhibiting NOS-dependent pathways in these systems, possibly at the level of NOS. Although opposite results in experimental animals have been published (Fitzgerald et al, 1995;Ikeda et al, 1999;Naassila et al, 1997;Shi et al, 1998;Srivastava et al, 1999), our results demonstrate that ethanol has an inhibitory action on nNOS pathways in nerve cell cultures. In SH-SY5Y cells, inhibition of nNOS for 2 days with the selective nNOS inhibitor PLA caused a significant increase in the number of mAChRs.…”

Expression of endothelial nitric oxide synthase gene in cultured porcine granulosa cells after FSH stimulation

“…As NO may be involved in ovulation (Shukovski & Tsafriri 1995, Bonello et al 1996, Yamauchi et al 1997) and differentiation of the granulosa cells (Hattori et al 1996, Nishida et al 2000, it is reasonable to propose that expression of eNOS mRNA preceded maximal expression of LH receptor mRNA in cultured granulosa cells. eNOS has been considered to be a constitutively expressed protein, but there are many reports of regulation of the expression of its gene , Bryant et al 1995, Van Voorhis et al 1995, Arnet et al 1996, JablonkaShariff & Olson 1997, El Dwairi et al 1998, Vega et al 1998, Hangai et al 1999, Srivastava et al 1999, Venkov et al 1999. In post-ischaemic rat retina, eNOS mRNA increased to a peak at 12 h, and decreased progressively beyond 24 h (Hangai et al 1999).…”

“…iNOS is transcriptionally regulated, whereas nNOS and eNOS are considered to be constitutively expressed. However, evidence accumulated in recent years indicates that these two isoforms are also subject to expressional regulation , Van Voorhis et al 1995, Bryant et al 1995, Arnet et al 1996, Jablonka-Shariff & Olson 1997, Vega et al 1998, El Dwairi et al 1998, Srivastava et al 1999, Hangai et al 1999, Venkov et al 1999. Changes in their expression may have physiological and pathophysiological consequences.…”

Possible interactions of the endothelial constitutive nitric oxide synthase genotype with alcohol drinking and walking time for high serum uric acid levels among Japanese

“…However, it was reported that ethanol induced a rapid increase of ecNOS protein and mRNA expression levels and activity [44][45][46][47][48]. Ethanol modulates tyrosine kinase activity [49], and tyrosine kinase regulates expression of ecNOS via posttranscriptional mechanisms [50,51].…”