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Biomedical subjects

P Eneroth

Publications and source records attributed to P Eneroth.

At least 289 records · Page 16Linked to original sources
PubMed1980

Toluene-induced activation of certain hypothalamic and median eminence catecholamine nerve terminal systems of the male rat and its effects on anterior pituitary hormone secretion.

Subacute exposure to high concentrations (500--1000 ppm) of toluene vapour led to an increase of noradrenaline levels in the subependymal layer of the median eminence (SEL) and to an increase of noradrenaline turnover within the subependymal layer, the paraventricular hypothalamic nucleus and the anterior periventricular hypothalamic nucleus (PV I). Increased dopamine levels in the lateral palisade zone of the median eminence (LPZ) and increased catecholamine turnover within the medial palisade zone (MPZ) were also produced. Measurement of the anterior pituitary hormone secretion showed a significant increase of FSH and delayed increase of corticosterone secretion following toluene exposure.

Animals↗
PubMed1980

Effects of acrylonitrile on rat liver cytochrome P-450, benzo(a)pyrene metabolism and serum hormone levels.

Intraperitoneal injections of acrylonitrile (AN), 33 mg/kg, into male rats daily for 3 consecutive days resulted in a 20% decrease in the liver microsomal content of cytochrome P-450. The in vitro formation of 9-hydroxy and 9,10-dihydrodiol metabolites of benzo(a)pyrene in liver microsomes was inhibited. Serum corticosterone levels were markedly decreased (30% of th values for control animals) demonstrating a disturbed pituitary-adrenal axis. A central effect of AN is supported by the finding that prolactin concentrations fell by approximately 60% in exposed animals. AN also induced a doubling FSH levels, whereas LH concentrations were the same as in the control animals. These results suggest an impaired spermatogenesis in the exposed animals.

Acrylonitrile↗
PubMed1980

Bacterial flora in semen before and after doxycycline treatment of infertile couples.

A group of men under investigation for infertility have been studied with regard to findings of aerobic and anaerobic bacteria in their ejaculates before and after medication. The group consisted of 27 men who received doxycycline concomitantly with their partners according to a fixed treatment schedule. Prior to medication 23 men delivered ejaculates which demonstrated bacterial growth. A total of 53 isolates were obtained. Following doxycycline treatment a significant number of men had a reduction in the number of isolates. The reduction was mainly confined to peptococci and propionibacteria. Of the 9 men whose partners subsequently conceived, 6 harboured peptococci and/or propionibacteria in their semen before but not after treatment. It is concluded that these results warrant more extensive studies of the possible part played by peptococci and propionibacteria in genital-tract infections in the male partners of infertile unions.

Bacteria↗
PubMed1980

Neonatal treatment with antioestrogen increases the diurnal rhythmicity in the sexual behaviour of adult male rats.

Male rats were given daily injections of the antioestrogen ethamoxytriphetol (MER-25, 100 microgram/day) or oil during the first 10 days of life. Rats treated with MER-25 showed a more pronounced diurnal rhythm in both mounting behaviour and lordosis behaviour than did oil-treated rats when tested as intact adults and after castration together with treatment with testosterone- or oestradiol-filled constant release implants. Serum levels of androgen varied markedly in samples obtained at four different times of the light : darkness (LD) cycle in both neonatal treatment groups and no significant LD-dependent pattern was obvious. Castration and treatment with testosterone implants produced stable androgen levels which showed little individual variation and did not vary with the LD cycle. The results supported the hypothesis that perinatal androgen stimulation affects the development of sexual behaviour in rats primarily by decreasing the diurnal rhythmicity of the behaviour of the adult.

Androgens↗
PubMed1980

Effects of hypothalamic deafferentation at different levels on metabolism of hepatic steroids in rats.

The metabolism of 4-[4-14C]androstene-3,17-dione in the microsomal fraction of livers from male and female rats was investigated after hypothalamic deafferentation at two levels. It was found that frontal deafferentation at the retrochiasmatic level caused a complete 'feminization' of hepatic steroid metabolism in the male rat but was without effect in the female animal. Transection rostral to the suprachiasmatic nuclei was without effect in both sexes. A complete transition from male to female hepatic steroid metabolism after retrochiasmatic deafferentation was reached on day 4 after the operation and persisted for at least 10 weeks. The present results, taken together with previous investigations, indicate that the release of a 'feminizing' factor from the pituitary gland of the male rat is inhibited by a factor produced in, or transported through, the periventricular anterior hypothalamic region including the suprachiasmatic area. No effect on the hepatic steroid metabolism was observed after binding of the rats suggesting that a diurnal rhythm is not essential to this control mechanism.

Androstenedione↗
PubMed1980

Episodic fluctuations in concentrations of androgen in serum of male rats: possible relationship to sexual behaviour.

Serum levels of androgen were higher during the late part of the light phase of the light : darkness (LD) cycle than during the late part of the dark phase during three consecutive days in intact male rats. The serum concentration of androgen in blood samples obtained at hourly intervals from individual male rats fluctuated markedly with occasionally as much as a tenfold difference between the highest and lowest values. Evidence was presented that endogenous pulses in the concentrations of androgen in serum of male rats occur during the late part of the light phase and the early and middle parts of the dark phase of the LD cycle. Induction of sexual behaviour by injections of testosterone in castrated rats depended on the time of injection, and the period of maximum behavioural sensitivity to testosterone coincided with the time of the LD cycle when pulses in androgen levels in serum normally occurred in intact rats. Injection of testosterone produced extremely high concentrations of androgen in serum within 0.5 h of injection but these levels declined rapidly thereafter. Testosterone implants, which produced low levels of androgen that did not vary with the LD cycle, were considerably more potent than testosterone injections in stimulating sexual behaviour in castrated rats.

Animals↗
PubMed1980

Changes in serum hormone levels during labor induced by oral PGE2 or oxytocin infusion.

The hormonal changes in maternal serum during parturition induced by amniotomy and oxytocin (OXY) infusion or oral prostaglandin E2 (PGE2) medication have been compared in 68 patients (33 women in the PGE2 group, 35 in the oxytocin group). The effect of PGE2 differed from that of oxytocin. Thus the prostaglandin elicited increases in total estriol (p < 0.001) and decreases in prolactin (p < 0.01), TSH (p < 0.05) and HPL (p < 0.05) from the basal level to that immediately before parturition. Maternal serum cortisol levels rose to the same extent in both treatment groups (p < 0.001). The significant (p < 0.05) increase occurred earlier among women receiving PGE2 (two hours into therapy), even though labor pain was experienced later in this group. The serum estriol elevation in these patients was significant three hours after start of therapy (p < 0.05). A similar time course was noted for the decrease of serum prolactin in PGE2 treated patients. The drop in maternal serum levels of HPL and TSH in the PGE2 group was significant only immediately prior to partus. Neither PGE2 nor oxytocin induced changes in maternal serum levels of HCG or alpha-fetoprotein or estradiol. Oxytocin but not PGE2 lead to a decrease in maternal serum progesterone concentrations; this was significant (p < 0.05--p < 0.01) only late in labor. Mixed umbilical serum levels of the hormones mentioned above were the same regardless of method of induction. Hence the increased maternal estriol concentrations during PGE2 treatment were not reflected in fetal blood. It is suggested that increases in maternal estriol levels during PGE2 medication are due to effects on the maternal enterohepatic circulation rather than on the fetoplacental unit. Irrespective of maternal treatment umbilical serum from female newborns contained statistically higher (p < 0.05) levels of estradiol and HCG than serum from male children.

Administration, Oral↗
PubMed1980

[Surgical management of pituitary adenomas with preservation of pituitary function (author's transl)].

Tumors of the pituitary gland comprise a large group of the intracranial tumors. As in all tumor surgery, early diagnosis is essential for the best outcome of treatment. However, the non-functioning adenomas are often diagnosed in their later stages of development as a result of the complexity of symptoms due to a mass lesion. In contrast, hormone-secreting adenomas give early symptoms which can be supported by reliable diagnostic laboratory findings and involve the production of growth hormone, prolactin and ACTH respectively. Using the transantro-sphenoidal route, our results of surgical removal of small tumors have been excellent, and microadenomas have been treated with preservation of normal pituitary function. However, an increasing size of the tumor considerably reduces the possibility of cure.

Adenoma↗
PubMed1980

Mecamylamine induced blockade of nicotine induced inhibition of gonadotrophin and TSH secretion and of nicotine induced increases of catecholamine turnover in the rat hypothalamus.

Nicotine treatment of normal male rats and of ovariectomized female rats results in increases of dopamine (DA), noradrenaline (NA) and adrenaline (A) turnover in the hypothalamus, especially within the median eminence. These effects may in part mediate the inhibition of gonadotrophin and TSH secretion produced by nicotine.

Animals↗
PubMed1979

Acute effects of zimelidine and alaproclate, two inhibitors of serotonin uptake, on neuroendocrine function.

The accumulation of 14C-5-hydroxytryptamine in human platelets in vitro and plasma levels of a number of hypophyseal hormones and cortisol in healthy male volunteers were determined after acute oral administration of zimelidine and alaproclate, two selective inhibitors of serotonin (5-HT) uptake. Alaproclate (100 mg) significantly inhibited the accumulation of 14C-5-HT by 42% at 90 minutes but showed no significant effect at 4 hours. At 200 mg the decrease in the accumulation was 55% after 90 minutes and 31% after 4 hours. Zimelidine (200 mg) caused a 72% decrease at 90 minutes and 73% at 4 hours. Plasma levels of prolactin, growth hormone, luteinizing hormone, follicle stimulating hormone, and thyroid stimulating hormone remained unchanged after zimelidine and alaproclate, and the levels were comparable to those after placebo. A physiological decline of plasma cortisol levels was noted in the morning during the test period of 4 hours, but there were slight differences in the secretory pattern after the different drugs used.

Adult↗
PubMed1979

Central control of lactogenic receptors in liver membranes: effect of hypothalamic deafferentation.

The regulation by the central nervous system of a lactogenic receptor, present in the rat liver, was studied. The receptor, which is present in very low concentration or absent in the male rat, can be induced by anterior hypothalamic deafferentation, resulting in a typically female level of the receptor in lesioned male animals. Our observations indicate an important role of the brain in regulation of peripheral lactogenic receptors.

Afferent Pathways↗
PubMed1979

Treatment with a single vaginal suppository containing 15-methyl PGF2 alpha methyl ester at expected time of menstruation.

Termination of early pregnancy, by vaginal administration of prostaglandin analogues, one to three weeks after the first missed menstrual period, has advantages and disadvantages in comparison with vacuum aspiration. Some of these may be reduced if the patient is treated earlier. In the present study the effect and safety of one vaginal administration of 2.5 to 3 mg 15-methyl-PGF2 alpha methyl ester around the expected time of menstruation was evaluated in 16 women exposed to the risk of pregnancy. The overall number of treatment cycles was 35 and pregnancy was confirmed by plasma beta-HCG in eight. The treatment resulted in bleeding in all the pregnant cycles while in the nonpregnant ones it only provoked spotting and bleeding did not begin until the expected time of menstruation. Treatment with 2.5 mg 15-methyl-PGF2 alpha methyl ester resulted in complete abortion in one of three women. If the dose was increased to 3 mg all five treated women aborted. In nonpregnant patients no changes in the levels of estradiol-17 beta or progesterone at any time during the 24-hour observation period were found. Serum cortisol and prolactin but not TSH levels started to increase two hours after the start of treatment and reached a maximum after five hours. The increase coincided with the onset of uterine pain. Ovulatory cycles as judged from basal body temperature occurred in the first menstrual cycle following treatment in all nonpregnant patients. Although possible to use as a "once a month treatment" it seems preferable since the dose is the same, to postpone treatment until menstruation is delayed for a week or more.

Abortion, Induced↗
PubMed1979

Reduction of androstenedione by skin in vitro and serum levels of gonadotrophins and androgens in men with hypospadias.

The reduction of 4-[1,2-3H]androstene-3,17-dione (androstenedione) in vitro by scrotal skin was measured in samples from nine men (16--34 years old) with hypospadias and from ten male control subjects. The reduction of androstenedione was also studied in axillary and upper arm skin of seven control subjects. Androstenedione was reduced to material with chromatographic characteristics of 5 alpha-androstane-3,17-dione and to 3 alpha- and 3 beta-hydroxy-5 alpha-androstan-17-one. No difference in 5 alpha-reductase activity (defined as the sum of these three metabolites formed) was found in scrotal skin from hypospadic and control men. The mean concentration of 5 alpha-dihydrotestosterone in serum from men with hypospadias was lower than that in serum from control subjects (P less than 0.01). The mean ratio of the serum concentrations of testosterone and 5 alpha-dihydrotestosterone was higher in hypospadic men than in control subjects (P less than 0.05). No differences between the two groups were found in the mean serum concentrations of LH, FSH, prolactin, dehydroepiandrosterone, androstenedione, testosterone or testosterone-binding globulin.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1979

A sexually dimorphic rhythm in oestradiol-activated lordosis behaviour in the rat.

Ovariectomized rats exposed to constant plasma levels of oestradiol showed a daily rhythm in lordosis behaviour, with high levels of lordosis occurring during the dark portion of the daily light: darkness cycle and low levels during the light period. Similarly treated male rats failed to show a rhythm in lordosis behaviour. However, neonatal castration permitted the expression of the lordosis rhythm in male rats; conversely, an injection of 1.25 mg testosterone propionate on day 4 of life abolished the rhythm in female rats. Pinealectomy, adrenalectomy or depletion of brain 5-hydroxytryptamine levels did not affect the periodicity in lordosis behaviour but lesions in the suprachiasmatic nuclei of the hypothalamus disrupted the rhythm. It is suggested that the daily rhythm in lordosis behaviour participates in the control of the termination of heat in the female rat and that the perinatal hormone milieu may exert permanent effects on periodic functions.

Animals↗