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PubMedDate not supplied

Species, sex, and developmental differences in the O- and N-dealkylation of ethylmorphine by hepatic microsomes.

3-O-[1'-14C]Ethylmorphine and ethylmorphine, respectively, were used to measure O- and N-dealkylase activities of hepatic microsomes. The well-known sex difference in the rate of N-delakylation in mature rats was not observed with O-dealkylation, nor did O-dealkylase activity increase as male rats reached maturity, as is the case with N-dealkylase activity. Accordingly, O-dealkylation represents only about 20% of the total dealkylase activity (O- + N-) in mature male rats, but about 50% in mature female rats. A comparison of the O- and N-dealkylating activities of hepatic microsomes from rats, mice, guinea pigs, and rabbits showed that both the rates of O- and N-dealkylation and the ratio of the two reactions vary greatly among animal species. These studies contribute to the evidence that different cytochrome P-450-dependent mono-oxygenase systems are involved in the O- and N-dealkylation of opium alkaloids.

Aging↗
PubMed1992

Sex-related differences in developmental rates of bovine embryos produced and cultured in vitro.

The classical concept of sex determination in mammals is that a Y chromosomal gene controls the development of the indifferent gonad into a testis. Subsequent divergence of sexual phenotypes is secondary to this gonadal determination. The most likely candidate gene is SRY (sex-determining region Y) in humans, and Sry in mouse. However, several lines of evidence indicate that sexual dimorphism occurs even before the indifferent gonad appears. Here we present evidence that bovine male embryos generally develop to more advanced stages than do females during the first 8 days after insemination in vitro. Corresponding relationships between both cell numbers and mitotic indices and sex were also seen. Although it is not clear whether this phenomenon involves factors originating before or after fertilization, these findings suggest that sex-related gene expression affects the development of embryos soon after activation of the embryonic genome and well before gonadal differentiation.

Animals↗
PubMed1976

Components of school anxiety: developmental trends and sex differences.

Dunn's School Anxiety Questionnaire was administered to 104 third through eighth graders (Study I) and 122 eighth graders (Study II). Significant decrements in anxiety with increasing age were found for worry (but not emotionality), report card anxiety, and failure anxiety. In Study I girls scored significantly higher than boys on emotionality (but not worry) and test anxiety. Sex differences were greater in Study II, girls scoring consistently higher. In Study II a worry-emotionality questionnaire administered immediately preceding a final examination correlated highly with School Anxiety Questionnaire scores. Results are taken as generally supportive of the multidimensional approach to the study of school anxiety.

Achievement↗
PubMed1978

Sex differences in responsiveness to infants: a developmental study of psychophysiological and behavioral responses.

Sex differences in responsiveness to infants were investigated by comparing physiological responses to infants with overt behavioral reactions. The former were assumed to be more biologically determined than the latter whereas overt behavioral responsiveness was presumed to be more affected by societal norms than were psychophysiological indices. The subjects were boys and girls in middle childhood and early adolescence. Psychophysiological indices showed that children, like parents, responded differentially to infant smiles and cries. As predicted, there were no sex differences on psychophysiological measures of responsiveness to babies. When permitted to interact with a baby, however, girls interacted more and ignored less than boys did. The results suggest that sex differences in overt responsiveness to babies are attributable to societal pressures rather than innate factors. Sex differences appear to wax and wane depending on the salience of sex stereotypy in differing developmental phases.

Adolescent↗
PubMed1992

Age and sex as factors influencing spontaneous exploration and object investigation by preadult rats (Rattus norvegicus).

This study examined developmental and sex differences in the exploratory and investigatory behaviors of Long-Evans rats (Rattus norvegicus). Littermate sextuplets were divided into sex-matched groups (at 30, 60, and 90 days of age) and were individually videotaped on 2 consecutive nights in an arena that contained stimulus objects. Multiple measures of locomotor exploration and object investigation increased significantly with age but were not influenced by sex. Older rats entered more quickly, were more active, spent more time in the arena, and spent more time investigating inanimate stimulus objects than did younger rats. Sex did not significantly affect most measures of open-field behavior; however, the data suggest that the sexes may begin to diverge by 90 days. These results suggest that preadult rats of both sexes are equipped early in development with similar strategies and repertoires for exploration and investigation.

Age Factors↗
PubMed1992

Ontogeny of cocaine hyperactivity and conditioned place preference in mice.

Conditioned place preference (CPP) procedures using jointly visual and tactile cues (white compartment with a wide-mesh metal floor versus black compartment with a narrow-mesh floor) were employed to assess the ontogenetic pattern of cocaine reinforcing properties in outbred CD1 mice. A classical 11-day-long schedule, in which the drug experience occurred in the initially less-preferred compartment ("biased" procedure, Spyraki 1988), served to study cocaine (0, 1, 5, or 25 mg/kg IP repeated four times at 48 h intervals) during the early postweaning stage (21-32 days). The result was a fully-fledged CPP at all cocaine doses. A subsequent experiment used a shortened (4-day) "unbiased" CPP schedule (animals assigned at random to drug experience in one or the other compartment); this enabled an assessment of the ontogenetic pattern of the drug action (single treatment, same dose range) in pups of both sexes at three different developmental ages (14-17, 21-24, or 28-31 days). At the 25 mg/kg dose, CPP developed in animals of all ages, while the 5 mg/kg dose was effective only in 21-24 day pups and the 1 mg/kg dose was ineffective. No significant sex differences were found, but the use of the unbiased procedure enabled a demonstration of an interaction between treatment, age, and type of CS. At the preweaning stage, CPP was due mainly to an increased preference for the black/narrow-mesh compartment, while at the early postweaning stage it consisted mainly of an increased preference for the white/wide-mesh compartment; at the late postweaning stage the cue and the treatment factor did not interact.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed2026

Maternal obesity in rats results in male-specific increases in genome-wide DNA methylation in postnatal offspring liver.

Male-specific peripubertal DNA demethylation in the liver has been reported in mice. Here, we investigated whether it also occurs in rats, the influence of maternal obesity and whether DNA demethylation changes contribute to observed sex-specific effects of maternal obesity in offspring. Female rats were fed a high-fat, high-sugar 'cafeteria' (Caf) diet before mating with standard chow-fed males. The offspring liver methylome and transcriptome were examined. Body weight was higher in Caf-fed dams prior to mating, during gestation and at parturition. Male and female offspring from Caf-fed dams had lower birth weights but higher adult weights and adiposity than offspring from chow-fed dams. A comparison of DNA methylation in 3-week-old weaner males versus female siblings from chow-fed dams did not reveal the male-specific DNA demethylation that was previously reported in mice. However, strong maternal diet effects in male weaner offspring methylation were observed. A comparison of female weaners from chow- versus Caf-fed dams showed a range of differences, with 39% of differentially methylated regions (DMRs) having higher methylation in Caf offspring and 61% of DMRs having higher methylation in chow offspring. In stark contrast, 99% of maternal-diet-induced DMRs in male weaner offspring had higher methylation in offspring from Caf-fed dams. This suggests that maternal obesity induces widespread hypermethylation in the male offspring liver at weaning. However, a comparison with RNA sequencing data revealed limited transcriptional changes at this developmental stage or in adult offspring. While these data highlight how environmentally sensitive DNA methylation is in the male rodent perinatal period, these methylation changes may not be a major contributor to sex differences in developmentally programmed liver disease.

Animals↗
PubMed1975

Effects of neonatal castration and testosterone injection on adult open-field behaviour in rats with atypical sex difference in defecation.

In the open-field test, male rats usually defecate more and ambulate less than females. A strain was studied in which the males defecate less than females, while still ambulating less. Infants of this strain were castrated (males) or injected with testosterone propionate (females) and tested in the open field as adults. There were significant effects of these neonatal treatments on ambulation, but not on defecation, in contrast to previous reports for the latter measure in rats showing a sex difference in defecation taking the usual direction. It is suggested that absence of the usual direction of a sex difference normally under the developmental control of androgen may indicate a genotype which has escaped from such control. Finally, a number of 'sibling' effects' were observed, i.e. effects on the adult behaviour of the members of one sex in a litter produced by treatments administered in infancy to members of the other sex.

Animals↗
PubMed1991

Sex-specific schedule in steroid response of rhombencephalic catecholaminergic neurons in vitro.

Morphological differentiation of tyrosine hydroxylase-immunoreactive neurons was investigated in dissociated cell cultures of rhombencephalon of male and female day 14 rat embryos grown in the presence or absence of sex steroids. Numbers of cells were counted and morphometrical measurements carried out of soma size and length of tyrosine hydroxylase-immunoreactive neurites (processes). Subtle sex differences in length of stained neurites, which were not yet present after 3 days in vitro, were observed after 6 days in cultures grown in the absence of sex steroids. Female tyrosine hydroxylase-immunoreactive neurites could be traced over longer distances than male ones. Daily treatment of cultures with testosterone or 17 beta-estradiol resulted in an increase of lengths of stained neurites of female neurons after 3 days and of male neurons after 6 days in vitro. Regarding cell numbers or soma size, there were no differences between genders or between controls and hormone-treated cultures. It is concluded that sex steroids promote the outgrowth of neurites from noradrenergic neurons within a gender-specific time frame. It appears that the critical period for developmental effects of sex steroids differs between males and females.

Animals↗
PubMed1992

Lectin-binding carbohydrates in sexual differentiation of rat male and female gonads.

Development and sexual differentiation of the mammalian gonad involve changes in the type and distribution of different proteins and glycoproteins in and around the epithelial gonadal cords, the future seminiferous tubules in the testis, and follicles in the ovary. To study changes in cellular carbohydrate-containing compounds in the sex-specific morphogenesis of rat gonads, sections from embryonic, fetal and early postnatal gonads were labelled with seven different fluorescein isothiocyanate (FITC)-conjugated plant lectins of various carbohydrate-binding specificities. Double labelling of laminin with tetramethylrhodamine isothiocyanate (TRITC)-conjugated antibodies was used to outline the epithelial tissues. From the results we conclude that the abundance and similar distribution of carbohydrates in the early gonads of both sexes supports their sexually indifferent nature. Furthermore, the basement membranes of the differentiating gonadal cords in both sexes have common features, which differ, however, from those of the other developing urogenital organs. Changes in carbohydrate composition appear with the sexual differentiation of the gonads; the similarity of the changes in lectin binding to the gonadal cords of embryonic and fetal male, and to postnatal female, suggests similar mechanisms of cell-cell interactions in both sexes although activated at different developmental stages. These carbohydrate specificities at the tissue level should be taken into account together with cell-type specific changes, e.g. in the formation of the zona pellucida, when the phenomenon of polymorphic expression of different compounds is integrated into theories of epithelial differentiation.

Animals↗
PubMed1992

Cranial growth in the squirrel monkey (Saimiri sciureus): a quantitative analysis using three dimensional coordinate data.

Improvements in data gathering technology have made it possible to quickly and accurately digitize large numbers of objects. The three dimensional coordinates of 44 homologous landmarks were obtained from a sample of 104 squirrel monkey (Saimiri sciureus) crania. After sorting by sex, the crania were assigned to one of four dental age groups. Two quantitative methods, Euclidean distance matrix analysis (EDMA) and finite element scaling analysis (FESA), were used to study craniofacial form change during growth within each sex. Form differences between the sexes at each developmental age were also examined. Both sexes show a small amount of cranial growth overall; however, there are areas of substantial local growth. These areas include the anterior neurocranium and basicranium, the basioccipital, and the anterior palate. Sexual dimorphism in the craniofacial complex is minimal. The most dimorphic regions are the orbitonasal portion of the lower face, the cranial base, and the palate.

Animals↗
PubMed1992

Control of constitutively-expressed developmentally-activated rat hepatic cytochrome P450 genes.

Cytochromes P450 (P450) collectively refer to a superfamily of heme-containing enzymes that use O2 and electrons from NADPH to insert a single atom of oxygen into any one of a large number of substrates. Two general classes of P450s exist; a relatively limited number of P450 forms, expressed in specialized tissues that are associated with pathways of steroidogenesis and a large number of forms responsible for metabolism of foreign compounds. Most of the latter P450s are expressed in liver, the primary site for metabolism of drugs, unusual dietary compounds and environmental pollutants. Numerous forms of P450 are expressed in liver of untreated animals and these are regulated quite differently. Both developmentally-programmed and sex-specific expressions have been observed. In this review, I will summarize recent findings on the mechanisms by which two P450 genes are regulated in livers of developing rats. The CYP2E1 gene is transcriptionally activated within a few hours after birth while the CYP2C6 gene is activated just prior to rats reaching puberty. These genes are under control of two transcription factors, HNF-1 alpha and DBP, respectively, that themselves are developmentally controlled.

Albumins↗
PubMed1992

Lateralized deficits in visual attention in males with developmental dopamine depletion.

Children with early treated phenylketonuria (ETPKU), a disorder associated with developmental dopamine depletion, were tested with a visual orienting paradigm to determine the existence of lateralized deficits in specific attentional operations. Male ETPKU subjects showed a right visual field impairment in disengaging attention, indicating left hemisphere dysfunction, and overall slowed reaction times. Female ETPKU and normal subjects did not differ. The results suggest that for males, dopamine depletion disrupts left hemisphere function. This finding has important implications for disorders with suspected developmental dopamine abnormalities, and may also illustrate how sex differences in functional lateralization develop in the normal brain.

Attention↗
PubMed1978

Epidemiological indicators of the origins of behavior disturbance as measured by the Bristol social adjustment guides.

Sex and social-class differences in juvenile behavior disturbance are quoted from two large surveys in Britain (N = 15,496) and Canada (N = 2527). These were significant in overreacting, but small or nonexistent among underreacting types of maladjustment. Comparable differences for social class and/or sex are quoted for developmental and health handicaps, perinatal mortality, and other congenital variables, notably the mother's smoking during the pregnancy. The greater prevalence among males over a wide range of deficits could not be accounted for by differing child-rearing practices, but seemd to be genetic. Similarly, the greater prevalence of overreacting maladjustment in lower-class children could not be explained in terms of cultural conflict, but rather as the outcome of prenatal stresses associated with child morbidity. A unifying theory accounting for both sets of phenomena could be found in mechanisms for the control of population numbers observed in many animal species.

Child↗
PubMed1992

[Importance of developmental psychopathology for understanding psychiatric disorders and diseases in childhood and adolescence].

Though the concept of developmental psychopathology is broadly discussed nowadays, a real integration of the different aspects of developmental psychology, developmental neurology and developmental physiology is not yet achieved. Elements that have to be considered to arrive at such an integrative view are pointed out. Sex differences and individual differences as well as the issue of continuity and change of behavior in the developmental process, the meaning of risk factors and protective factors and prediction research have to be considered. The importance of the developmental perspective with respect to the classification of psychopathological features is stressed and the problems that arise when trying to integrate this perspective into the existing classification schemes. Finally, it is shown how--by means of logistic models--the complex interaction between very heterogeneous factors, for example the connection between biological and psychosocial influences in the developmental process, can be described.

Adolescent↗