Oct-4 transcription factor is differentially expressed in the mouse embryo during establishment of the first two extraembryonic cell lineages involved in implantation.

Oct-4 is the earliest expressed gene known to encode a transcription factor which is developmentally regulated during mammalian embryogenesis. In order to understand the role of Oct-4 in early murine embryogenesis, we carried out an analysis of the temporal and spatial pattern of protein expression. We report the presence of Oct-4 protein in cultured cells and murine embryos as determined by immunohistochemistry using confocal microscopy. Oct-4 protein is present in both embryonic stem cells and embryonal carcinoma cells, but is down-regulated following differentiation of these cells by culture in the absence of leukemia inhibitory factor or in the presence of retinoic acid, respectively. In embryos, the protein is found at low levels in unfertilized eggs and is localized predominantly to the pro-nuclei upon their formation following fertilization. The protein is present in the nuclei in all cleavage stages, but following differentiation of the trophectoderm at the blastocyst stage, Oct-4 protein is only expressed in the inner cell mass. The pattern of protein expression to this stage correlates well with previously reported in situ hybridization results; however, a striking difference was seen in primitive endoderm cells which had begun to differentiate and migrate along the inner surface of the trophectoderm. In direct contrast to RNA localization studies which demonstrate that there are only low levels of Oct-4 transcripts in primitive endoderm cells, protein expression in these early migrating cells is higher than in the inner cell mass.

Expression of mouse PDGF-A and PDGF alpha-receptor genes during pre- and post-implantation development: evidence for a developmental shift from an autocrine to a paracrine mode of action.

We examined the expression of platelet-derived growth factor (PDGF)-A and the PDGF alpha-receptor in pre-implantation and early post-implantation mouse embryos. At two-cell and blastocyst stages, all cells express mRNA and protein for both ligand and receptor. In contrast, early post-implantation embryos express PDGF-A chain mRNA in both embryonic ectoderm and in the ectoderm lining the ectoplacental cavity, while mRNA for PDGF alpha-receptor is localized to the mesoderm layers of both embryonic and extra-embryonic membranes. At days 3.5 and 7.5, receptors are demonstrably functional in response to exogenous PDGF-AA. We propose that chronic autostimulation of PDGF alpha-receptors occurs in pre-implantation embryos, whereas, following implantation, early mesoderm development is dependent on stimulation by ectodermally produced PDGF-A.

Alcohol use, marihuana smoking, and sexual activity in women.

This report describes a prospective study of social drinking, marihuana smoking, and sexual activity by 26 healthy adult women (mean age 26.8 years). Each subject completed daily questionnaires for 3 consecutive menstrual cycles, and recorded menstrual cycle status, quantities and frequencies of alcohol consumption, marihuana smoking, and sexual activity. Consistent patterns of alcohol consumption, marihuana smoking, and sexual activity were reported across all 3 menstrual cycles. Heavy drinkers (mean greater than or equal to 1.80 drinks per day) were more likely to smoke marihuana than moderate drinkers (mean less than or equal to 1.75 drinks per day) and they also smoked significantly more marihuana (p less than 0.05). Neither age nor frequency of sexual activity were related to patterns of alcohol or marihuana consumption.

Alcohol effects on naloxone-stimulated luteinizing hormone, prolactin and estradiol in women.

Plasma luteinizing hormone (LH), estradiol, prolactin and progesterone levels were measured in nine normal adult women prior to and following administration of naloxone and oral ingestion of ethanol or placebo-control solution. Each subject served as her own control in a double-blind study carried out during the midluteal phase of the menstrual cycle. The mean (+/- SD) progesterone level was 13.9 +/- 1.3 during control conditions and 13.9 +/- 1.7 during alcohol conditions. The mean peak blood alcohol level was 100 +/- 13 mg/dl within 45-60 min after initiation of drinking. Under placebo-control conditions, naloxone stimulated a significant increase in plasma LH and prolactin but did not increase estradiol or progesterone. Alcohol did not attenuate the significant naloxone stimulation of LH, and progesterone levels were equivalent under alcohol and control conditions. Alcohol significantly enhanced naloxone stimulation of prolactin and estradiol. Alcohol administration significantly augmented the naloxone-induced increase in plasma prolactin levels. After alcohol administration, naloxone also induced a significant increase in plasma estradiol levels, which was sustained throughout the 180-min sampling period. The mechanisms underlying alcohol's enhancement of naloxone-stimulated prolactin and estradiol remain to be determined. The alcohol-related increase in naloxone-stimulated prolactin secretion may reflect increased hypothalamic and/or pituitary sensitivity to alcohol following endogenous opioid blockade by naloxone or an effect of increased estrogen levels. The significant increase in plasma estradiol levels following concurrent naloxone and alcohol administration may occur as a consequence of alterations in steroid biotransformation associated with intrahepatic ethanol catabolism.

Acute ethanol administration enhances plasma testosterone levels following gonadotropin stimulation in men.

Plasma levels of LH, FSH, prolactin (PRL), and testosterone (T) were assessed in six normal men following administration of a pharmacologic dose of gonadotropin releasing hormone (GnRH) (500 micrograms iv over a one-min period) with concomitant oral administration of either ethanol (0.695 g/kg of body weight over a 15-min period) or ethanol placebo. Acute ethanol administration had no effect on the response of either LH or FSH to GnRH. PRL levels increased following GnRH and administration of both ethanol and ethanol placebo. Ethanol administration enhanced the T response to GnRH (p less than 0.001 vs placebo). During the placebo condition, T levels did not rise significantly until 100 min after GnRH administration, at which time the mean increment over baseline was 101 +/- 20 ng/dl (+/- SEM). In contrast, following ethanol intake, T levels were significantly elevated within 30 min after GnRH administration, at which time the mean increment over baseline was 187 +/- 42 ng/dl. The mean T increments were 304 +/- 62 and 472 +/- 77 ng/dl, respectively, 60 and 105 min following GnRH and ethanol administration. The increase in T levels following acute ethanol intake and concomitant gonadotropin stimulation is in contrast to the well-documented effect of chronic ethanol intake on suppression of testosterone synthesis by testicular Leydig cells.

Cigarette smoking by women: interactions with alcohol use.

Cigarette smoking increased during alcohol self-administration in comparison to an alcohol-free baseline in 24 women given access to alcohol for 21 days. Heavy smokers (25 or more cigarettes per day) increased smoking significantly during drinking (P less than 0.05). Analysis of tobacco smoking by level of alcohol consumption showed that both heavy and moderate alcohol users increased smoking significantly during alcohol availability (P less than 0.05, 0.01). The heavy and moderate smokers smoked significantly more between noon and midnight (P less than 0.001) than at other times when alcohol was available. The rate of cigarette smoking (defined by inter-cigarette intervals) was faster during alcohol self-administration than during the alcohol-free baseline. Heavy smokers smoked most cigarettes at intervals of 11-20 min during heavy or moderate drinking. During the pre-alcohol baseline, these women smoked most cigarettes at intervals of 21-30 or 31-40 min. Most women (70-74%) also increased tobacco smoking at the premenstruum. Both heavy and occasional smokers increased smoking at the premenstruum significantly more than the moderate smokers (P less than 0.05). All women reported increased psychological discomfort at the premenstruum on the Premenstrual Assessment Form (PAF) but reports of physical discomfort were more marked in women who smoked less at the premenstruum. These data extend previous findings in men that alcohol consumption is associated with increased cigarette smoking to female social drinkers.