Cs Karabélyos

Changes in sexual behavior of adult male and female rats neonatally treated with vitamin D3

1 Neonatal treatment of rats with vitamin D3 resulted in a change of sexual behavior in adulthood. 2 2.5 mg vitamin D 3 completely inhibited the ejaculation of males without any apparent influence on sexual desire. 250 mg vitamin D3 influenced both the desire and ejaculation. 3 Sexual activity of females was depressed by both doses. 4 The experiments demonstrate that vitamin D3, a steroid in structure, given in the critical period of hormonal imprinting may influence steroid hormone-receptor commanded events for life, in a way similar to the effects exhibited by synthetic steroid hormone analo gues and benzpyrene in earlier studies.

Transgenerational effect of a single neonatal benzpyrene treatment (imprinting) on the sexual behavior of adult female rats

Male and female rats were neonatally treated with a single dose of benzpyrene. The adult animals were mated inter se, forming control-control, benzpyrene (female)-control, benzpyrene (male)-control, and benzpyrene-benzpyrene treated couples. In the F 1 and F2 generations (without any further treatment) the femaless sexual behavior was tested to Meyerson index and lordosis quotient after ovariectomy and hormone treatment, using experienced males. In the F1 generation both indices were significantly reduced in the maternally treated, paternally untreated groups, however this reduction was not present in the group where the treatment was maternal and paternal alike. In the F2 generation, beside the more expressed reduction in the grandmaternally treated group, a moderate reduction in the sexual activity of progenies having treated grandfather or two treated grandparents were observed. The experiment call attention to the transgenerational sexual behavioral effect of a dangerous environment pollutant, benzpyrene.

Impact of single neonatal serotonin treatment (hormonal imprinting) on the brain serotonin content and sexual behavior of adult rats

Hormonal imprinting takes place perinatally at the first encounter between the developing receptor and its target hormone. As a consequence of imprinting the receptor accomplishes its maturation and reaches the binding capacity characteristic to the adult age. In the excess of target hormone or presence of molecules similar to the target hormone, which are able to bind to the unmatured receptors, faulty imprinting develops with life-long consequences. At present, serotonin was given to neonatal rats and their sexual activity, brain serotonin level and steroid receptors binding capacity was measured in adult age. Brain serotonin level was significantly reduced in males striatum and parallel with this, males sexual activity significantly increased. In other regions of the male brain (prefrontal cortex, hypothalamus, hippocampus) there was a statistically non-significant tendency for a decrease in serotonin level. No significant differences were detected in female brain values, and there was only slight change in females sexual activity. There was also no change in the binding capacity of thymic glucocorticoid and uterine estrogen receptors. The experiments call attention to the possibility of perinatal imprinting by a neurotransmitter causing changes in brain neurotransmitter level for life, which is manifested in altered sexual activity.

Effect of fetal digoxin exposure (imprinting) on the sexual behavior of adult rats.

1. Digoxin exposure of rat fetuses at the 15th, 17th and 19th day of pregnancy by treating the mother (with 9 microg digoxin altogether) caused alterations in the sexual behavior of adult rats (3-month-old males and six-month-old ovariectomized and hormone-treated females). 2. The number of active males was significantly higher in the treated group and ejaculation as well as multiple ejaculation occurred only here. Females also were more receptable after fetal digoxin treatment. It is known from the literature that long-term digoxin treatment in adult age influences (reduces) the male sexual activity in humans. In the rat, the opposite effect was observed after fetal treatment. 3. The experiments call attention to the prolonged effect of fetal digoxin exposure caused by the treatment of the mother.

Effect of single neonatal vitamin D3 treatment (hormonal imprinting) on the bone mineralization of adult non-treated and dexamethasone treated rats.

Hormonal imprinting (the first encounter between the hormone and receptor after birth) is needed for the normal development of receptor. Presence of the appropriate hormone in excess, or its absence, as well as presence of hormone-like molecules able to bind to the maturing receptor in this time, can cause faulty imprinting. In this experiment the effect of neonatal treatment with a single dose of 0.05 mg cholecalciferol (vitamin D3) was studied by bone densitometry. The treatment caused significant decrease of body weight in 3-month old females and also significant reduction of bone mineral density (BMD) and bone mineral content (BMC) in males. Dexamethasone treatment of 3-month old rats for 10 days increased BMD in males and BMC in females without affecting body weight. The double treatment (vitamin D neonatally and dexamethasone when adult) decreased the body weight of both sexes and increased BMD in males, and BMC, BMD/bw and BMC/bw in both sexes, related to the control or the only vitamin D treated groups. Considering the hormonal imprinting effect of neonatal vitamin D treatment at glucocorticoid receptorial level in other experiments, similar effects also can be supposed for vitamin D itself, manifested in the changes of bone mineralization.

Effect of neonatal glucocorticoid treatment on bone mineralization of adult nontreated, dexamethasone-treated or vitamin D3-treated rats.

1. Single neonatal dexamethasone (DEX) treatment significantly decreased the body weights of 5-month old male rats. There was no significant difference in females. 2. Bone mineral density (BMD) of neonatally DEX-treated male rats and bone mineral content (BMC) of double DEX-treated (neonatally and in adult age) males were reduced. 3. BMD and BMC calculated to body weight were highly significantly increased after neonatal or double DEX treatment in males. In females only BMC/body weight was elevated after double DEX treatment. 4. Adult vitamin D treatment completely compensated for the changes caused by single or double DEX treatment. 5. The results call attention to the imprinting effects of neonatal glucocorticoid treatment, which were manifested in changes of body weight and bone mineral mass. At the same time the gender-dependence of this phenomenon was demonstrated.

Effect of perinatal synthetic steroid hormone (allylestrenol, diethylstilbestrol) treatment (hormonal imprinting) on the bone mineralization of the adult male and female rat.

Neonatal treatment with allylestrenol or diethylstilbestrol (DES) reduced the bone mineral content (BMC/bw) of the adult (four months old) female rats, without influencing bone mineral density (BMD/bw). In males these neonatal treatments elevated BMC and BMD alike. Ovariectomy alone decreased BMC and BMD alike; however the neonatal hormone treatments did not influence this reduced value. Ovariectomy of two months old animals increased body weight without the influence of neonatal hormone treatments. In adult males, the body weight was reduced significantly by neonatal DES and non-significantly by neonatal allylestrenol treatment. The experiments call attention to the possible human bone-effects of allylestrenol, which was used in the last decades as medication protecting endangered pregnancies.

Effect of contraceptive treatment on thymic glucocorticoid receptors and hepatic microsomal enzyme system of adult rats.

Contraceptive steroid treatment accounted for about a 30 per cent decrease in the number of thymic glucocorticoid receptors of adult rats. Neonatal allylestrenol treatment had no influence on that treatment. The activity of the hepatic microsomal (PSMO) enzyme system was not changed by the contraceptive treatment. It appears that contraceptive treatment may account for overlaps on receptors in adulthood.