LORDOSIS BEHAVIOUR IN MALE, FEMALE AND ANDROGENIZED FEMALE RATS

1976 ◽  
Vol 70 (3) ◽  
pp. 409-420 ◽  
Author(s):  
P. SÖDERSTEN
Keyword(s):  
Testosterone Propionate ◽  
Female Rats ◽  
Male Rats ◽  
High Dose ◽  
Normal Female ◽  
Adult Rats ◽  
Oestradiol Benzoate ◽  
Series Of Experiments ◽  
Lordosis Behaviour ◽  
Dose Dependent

SUMMARY Sex differences in the lordosis response of adult rats to ovarian hormones were studied in a series of experiments. Male rats were less sensitive to oestradiol benzoate (OB, a single injection of 10, 100 or 1000 μg/kg or seven daily injections of 2, 10 or 50 μg/kg) than were female rats. Oestradiol benzoate-primed (10 μg/kg) female, but not male, rats showed dose-dependent responses to progesterone (0·4, 2·0 or 10·0 mg/kg). Male rats responded clearly to progesterone (2 mg/rat) only when primed with a high dose of OB (100 μg/rat). Display of the whole pattern of female sexual behaviour was induced in male rats by treatment with 100 μg OB and 2 mg progesterone. Female rats treated with 1 mg testosterone propionate (TP) on day 4 of life, ovariectomized as adults and tested under the same endocrine conditions as the rats described above, retained behavioural OB sensitivity but responded poorly to progesterone. Evidence is presented that ovarian secretions during development significantly modify the response of neonatally TP-treated and normal female rats to OB in adulthood.

ENZYME ACTIVITY IN KIDNEY, ADRENAL AND GONADAL TISSUE OF RATS TREATED NEONATALLY WITH ANDROGEN OR OESTROGEN

1975 ◽  
Vol 67 (3) ◽  
pp. 317-326 ◽  
Author(s):  
R. GHRAF ◽  
H.-G. HOFF ◽  
E. R. LAX ◽  
H. SCHRIEFERS
Keyword(s):  
Enzyme Activities ◽  
Testosterone Propionate ◽  
Single Injection ◽  
Female Rats ◽  
Male Rats ◽  
Normal Female ◽  
Hormone Metabolism ◽  
Adult Rats ◽  
Fourfold Increase ◽  
Activity Of Enzymes

SUMMARY A single injection of 300 μg oestradiol benzoate (OEB) or 1·25 mg testosterone propionate (TP) on day 1 of life led to significant changes in the activity of enzymes involved in steroid hormone metabolism in kidney, adrenal and gonadal tissues of adult rats. In the kidney, the enzyme activities of male rats reacted to OEB, but not TP, by the development of normal female levels. With one exception the enzyme activities of the kidney of female rats did not respond to either steroid. In the adrenal of both sexes 5α-reductase reacted to OEB, but not TP treatment, by a fourfold increase in activity. In the ovary all the enzymes investigated responded both to OEB and TP treatment by a fall in activity; 20α-hydroxysteroid dehydrogenase activity fell to undetectable levels. In the testis, OEB and TP treatment led to contrasting effects. With the exception of 5α-reductase all the enzymes tested in this organ responded to OEB by a rise in activity. Where TP had any effect, it produced a slight decrease in activity.

scholarly journals Different mechanisms of regulation of nuclear reduced nicotinamide–adenine dinucleotide phosphate-dependent 3-oxo steroid 5α-reductase activity in rat liver, kidney and prostate

1974 ◽  
Vol 142 (2) ◽  
pp. 273-277 ◽  
Author(s):  
Jan-Åke Gustafsson ◽  
Åke Pousette
Keyword(s):  
Testosterone Propionate ◽  
Reductase Activity ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Female Rats ◽  
Male Rats ◽  
Regulatory Mechanisms ◽  
Oestradiol Benzoate ◽  
Liver And Kidney ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Hydroxy Steroid

The regulatory mechanisms involved in the control of the nuclear NADPH-dependent 3-ketosteroid 5α-reductase (5α-reductase) activity were studied in liver, kidney and prostate. The substrate used was [1,2-3H]androst-4-ene-3,17-dione (androstenedione) (for liver and kidney) or [4-14C]androstenedione (for prostate). The hepatic nuclear 5α-reductase activity was greater in female than in male rats, was greater in adult than in prepubertal female rats, increased after castration of male rats, but was not affected by treatment with testosterone propionate or oestradiol benzoate. These regulatory characteristics are in part different from those previously described for the hepatic microsomal 5α-reductase. The renal nuclear metabolism of androstenedione, i.e. 5α reduction and 17β-hydroxy steroid reduction, was relatively unaffected by sex, age, castration and treatment with testosterone propionate. However, treatment of castrated male rats with oestradiol benzoate led to a significant increase in the 5α-reductase activity and a significant decrease in the 17β-hydroxy steroid reductase activity. Finally, the nuclear 5α-reductase activity in prostate was androgen-dependent, decreasing after castration and increasing after treatment with testosterone propionate. In conclusion, the nuclear 5α-reductase activities in liver, kidney and prostate seem to be under the control of distinctly different regulatory mechanisms. The hypothesis is presented that whereas the prostatic nuclear 5α-reductase participates in the formation of a physiologically active androgen, 5α-dihydrotestosterone, this may not be the true function of the nuclear 5α-reductase in liver and kidney. These enzymes might rather serve to protect the androgen target sites in the chromatin from active androgens (e.g. testosterone) by transforming them into less active androgens (e.g. 5α-androstane-3,17-dione and/or 5α-dihydrotestosterone).

EFFECTS OF TESTOSTERONE MEDIATED OR MODULATED BY PITUITARY FACTORS

1975 ◽  
Vol 67 (1) ◽  
pp. 71-79 ◽  
Author(s):  
P. DE MOOR ◽  
M. ADAM-HEYLEN ◽  
H. VAN BAELEN ◽  
G. VERHOEVEN
Keyword(s):  
Body Weight ◽  
Testosterone Propionate ◽  
Total Body Weight ◽  
Seminal Vesicles ◽  
Female Rats ◽  
Male Rats ◽  
Intact Male ◽  
Adult Rats ◽  
Organ Weights ◽  
Total Body

SUMMARY Adult rats of both sexes were either gonadectomized or hypophysectomized and gonadectomized. Three to eight weeks later they were treated for 14 consecutive days with oil or with 75 or 200 μg testosterone propionate (TP) per 100 g body weight. The animals were killed and for each sex the gonadectomized animals were compared with the hypophysectomized-gonadectomized animals as far as their NADPH- and NADH-dependent 3α-hydroxysteroid dehydrogenases (3α-HSD) in renal microsomes, transcortin levels in serum and five organ weights relative to total body weight were concerned. For two of the latter, i.e. the relative kidney and prostatic weights, no significant differences were found. Transcortin levels, relative adrenal weights and renal NADPH-dependent 3α-HSD activities were higher in oil-treated gonadectomized animals than in oil-treated hypophysectomized-gonadectomized animals. The opposite was found for the relative weights of uterus and seminal vesicles and renal NADH-dependent 3α-HSD activities. These differences between gonadectomized and hypophysectomized-gonadectomized animals disappeared after TP treatment as far as transcortin levels were concerned but remained for the five other parameters. After gonadectomy sexual differences subsisted for all parameters studied. But whereas intact male rats had higher NADH-dependent 3α-HSD activities than female rats the opposite was found after gonadectomy. After gonadectomy plus hypophysectomy the between sex differences disappeared as far as transcortin levels were concerned but remained in the other parameters studied.

SENSITIVITY OF ANTERIOR HYPOTHALAMIC AREAS TO GONADAL STEROID IMPLANTATION IN ANDROGENIZED FEMALE RATS

1977 ◽  
Vol 74 (2) ◽  
pp. 315-NP ◽  
Author(s):  
A. DANGUY ◽  
J. L. PASTEELS ◽  
F. ECTORS
Keyword(s):  
Single Injection ◽  
Mammary Glands ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Male Rats ◽  
Control Synthesis ◽  
Normal Female ◽  
Immunofluorescence Studies ◽  
Oestradiol Benzoate ◽  
Stimulation Of

A single injection of 1 mg of a complex of testosterone esters on day 5 of life was used to prepare constantly oestrous rats. Such androgenized female rats were then ovariectomized and submitted to stereotaxical implantation of 1 μg oestradiol benzoate, 5 μg testosterone isobutyrate or, as a control, 10 μg cholesterol in the anterior hypothalamic areas. The effects of the steroids on plasma and pituitary FSH and LH were assessed by radioimmunoassay. As reported previously by us in normal female and male rats, the preoptic–suprachiasmatic area (POA) was able to control synthesis and secretion of both gonadotrophins and did not lose its sensitivity to oestradiol and testosterone in androgenized rats. Evidence for enhanced prolactin secretion in androgenized rats was derived from immunofluorescence studies of the pituitary gland and from histology of the mammary glands. In this respect the condition of the androgenized females was opposite to that of the males. The present work demonstrated that stimulation of prolactin secretion in androgenized female rats resulted from oestrogen action due to permanent oestrus rather than from impairment of hypothalamo-hypophysial relationships. Indeed, prolactin stimulation was suppressed when the androgenized rats were ovariectomized and restored when they were subsequently implanted with oestradiol in the POA.

EFFECTS OF ANTI-OESTROGEN TREATMENT OF NEONATAL MALE RATS ON LORDOSIS BEHAVIOUR AND MOUNTING BEHAVIOUR IN THE ADULT

1978 ◽  
Vol 76 (2) ◽  
pp. 241-249 ◽  
Author(s):  
P. SÖDERSTEN
Keyword(s):  
Testosterone Propionate ◽  
Neonatal Rat ◽  
Male Rats ◽  
Glans Penis ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Oestrogen Treatment ◽  
Oestradiol Benzoate ◽  
Sexual Glands ◽  
Lordosis Behaviour

Male rats were treated daily with 100 μg of the anti-oestrogen ethamoxytriphetol (MER-25) or oil during the first 10 days of life and tested for lordosis behaviour and mounting behaviour as intact adults, after castration and after castration and oestradiol benzoate or testosterone propionate treatment. The MER-25-treated rats showed higher levels of lordosis behaviour than oil-treated rats in all four treatment groups. Under each of these endocrine conditions, except after castration alone, the MER-25-treated rats showed a reduced capacity to ejaculate. Treatment of the neonatal rat with MER-25 reduced body weight in adulthood but did not change the weight of the accessory sexual glands, the testes, the number of cornified papillae on the glans penis or plasma testosterone concentrations during development. The response of the accessory sexual glands and cornified papillae on the glans penis to treatment with oestradiol benzoate or testosterone propionate after castration in adulthood was unaffected by treatment with MER-25. It is suggested that formation of oestrogen in the neonatal male rat brain from testosterone in the circulation inhibits the capacity to show lordosis behaviour and facilitates the capacity to ejaculate in response to gonadal hormone treatment in adulthood.

RELATIONSHIP BETWEEN THE PITUITARY GLAND AND GONADAL STEROIDS: INVOLVEMENT OF A HYPOPHYSIAL FACTOR IN REDUCED α2u-GLOBULIN AND INCREASED TRANSCORTIN CONCENTRATIONS IN RAT SERUM

1978 ◽  
Vol 78 (1) ◽  
pp. 31-38 ◽  
Author(s):  
G. VANDOREN ◽  
H. VAN BAELEN ◽  
G. VERHOEVEN ◽  
P. DE MOOR
Keyword(s):  
Pituitary Gland ◽  
Testosterone Propionate ◽  
Single Injection ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Male Rats ◽  
Rat Serum ◽  
Mediated Effects ◽  
Male And Female Rats ◽  
Oestradiol Benzoate

Evidence is presented that the level of α2u-globulin in the serum of male rats depends, at least in part, on neonatal androgens. After castration of adult animals the concentration of this protein falls but remains measurable, whereas in intact or ovariectomized female rats α2u-globulin cannot be detected. Moreover, α2u-globulin is found in adult male and female rats gonadectomized at birth and treated with a single injection of testosterone propionate immediately thereafter. The mechanism by which neonatal androgens increase the concentration of α2u-globulin has been investigated. Transplantation of a supplementary pituitary gland under the renal capsule of male rats resulted in reduced levels of α2u-globulin and increased levels of transcortin. The changes discussed here were observed only in those animals in which the transplant was functional and they were amplified or reversed by modulators of prolactin secretion such as oestrogens or bromocriptine respectively. The hypothesis is advanced that neonatal androgens stimulate the production of a hypothalamic inhibitory factor that controls the secretion of prolactin, or another hypophysial hormone subjected to similar neuroendocrine control. Measurements in gonadectomized animals and in rats receiving both oestradiol benzoate and bromocriptine indicate that, besides these pituitary-mediated effects, both oestrogens and androgens exert direct effects on the level of α2u-globulin.

scholarly journals Repeated exposure to chlorpyrifos is associated with a dose-dependent chronic neurobehavioral deficit in adult rats

2021 ◽  
Author(s):  
Ana CR Ribeiro ◽  
Elisa H Hawkins ◽  
Fay M Jahr ◽  
Joseph L McClay ◽  
Laxmikant S Deshpande
Keyword(s):  
Molecular Mechanisms ◽  
Low Dose ◽  
Forced Swim Test ◽  
Preference Test ◽  
Complete Recovery ◽  
Male Rats ◽  
High Dose ◽  
Adult Rats ◽  
Dose Dependent

Organophosphate (OP) chemicals include commonly used pesticides and also chemical warfare agents, and mechanistically they are potent inhibitors of the cholinesterase (ChE) enzyme. While a chronic low-dose OP exposure does not produce acute cholinergic crises, epidemiological studies report long-term neuropsychiatric issues including depression and cognitive impairments in OP-exposed individuals. Chlorpyrifos (CPF) is one of the most widely used pesticides worldwide. Multiple laboratory studies have reported on either the long-term behavioral effect of a single, high-dose CPF or studied sub-chronic behavioral effects particularly the motor and cognitive effects of repeated low-dose CPF exposure. However, studies on chronic mood and depression-related morbidities following repeated sub-threshold CPF doses that would mimic occupationally-relevant OP exposures are lacking. Here, adult male rats were injected with CPF (1, 3, 5, or 10 mg/kg/d, s.c.) for 21-days. Dependent on the CPF dose, ChE activity was inhibited approximately 60-80% in the blood and about 20-50% in the hippocampus at 2-days after the end of CPF exposures. Following an 11-week washout period, CPF-treated rats exhibited a dose-dependent increase in signs of anhedonia (sucrose preference test), anxiety (open-field and elevated plus-maze), and despair (forced swim test) despite a complete recovery of ChE activity at this stage. We speculate that both cholinergic and non-cholinergic mechanisms could play a role in the development of chronic OP-related depressive outcomes. The proposed CPF exposure paradigm could provide an ideal model to further study molecular mechanisms underlying cause and effect relationships between environmental OP exposures and the development of chronic behavioral deficits.

Neonatal testosterone potentiates stimulated prolactin secretion in adult oestrogen-primed rats

1986 ◽  
Vol 109 (1) ◽  
pp. 57-60 ◽  
Author(s):  
R. G. Dyer ◽  
S. Mansfield
Keyword(s):  
Testosterone Propionate ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Neonatal Exposure ◽  
Adult Rats ◽  
Blood Samples ◽  
Before And After ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT Blood samples were collected from oestrogen-primed gonadectomized adult rats before and after electrical stimulation of the preoptic part of the hypothalamus. Six groups of rats were used for the experiments. These were (a) males castrated on the first day of life, (b) males castrated after puberty, (c) females ovariectomized after puberty and (d), (e) and (f) females given testosterone propionate at birth (1·25, 0·125 and 0·0125 mg/rat respectively). Neonatal exposure of the female rats to testosterone caused a dose-dependent increase in the amounts of prolactin released to levels significantly (P<0·01) higher than those observed in male animals and in untreated females. The results indicate that although neonatal testosterone inhibits oestrogen-stimulated prolactin secretion in adult rats, the neuroendocrine apparatus controlling secretion of the hormone is capable of being activated to greater effect after exposure to androgens at the time of birth. J. Endocr. (1986) 109, 57–60

THE INFLUENCE OF A SINGLE HIGH DOSE OF OESTRADIOL BENZOATE ON THE ICSH-CONTENT IN THE SERUM OF GONADECTOMIZED MALE AND FEMALE RATS

1965 ◽  
Vol 49 (2) ◽  
pp. 231-238 ◽  
Author(s):  
T. Swelheim
Keyword(s):  
Anterior Pituitary ◽  
Single Injection ◽  
Female Rats ◽  
Male Rats ◽  
Ventral Prostate ◽  
High Dose ◽  
Male And Female ◽  
Single High Dose ◽  
Male And Female Rats ◽  
Oestradiol Benzoate

ABSTRACT A single injection of 50 μg oestradiol benzoate, administered at 11 a.m. to adult female rats which had been spayed 14 days previously and had since been treated with 0.5 μg oestradiol benzoate daily, led to an increase in the ICSH-content of the serum, which was determined 29 hours after the injection. In an identical experimental design a decrease in the ICSH-content of the serum was found in adult male rats. ICSH-determinations were carried out by the ventral prostate assay. A stimulating effect upon the ventral prostate of oestrogen present in the serum used for the above determinations was excluded. At the time when the changes in the serum were established, there were no demonstrable changes in the ICSH-content of the anterior pituitary gland in both sexes. The existence of a fundamental sex difference in the response to a single high dose of oestrogen is suggested.

EFFECTS OF DIHYDROTESTOSTERONE AND OESTRADIOL ON SEXUAL DIFFERENTIATION IN MALE RATS

1980 ◽  
Vol 84 (3) ◽  
pp. 397-407 ◽  
Author(s):  
P. VAN DER SCHOOT
Keyword(s):  
Sexual Differentiation ◽  
Testosterone Propionate ◽  
Neonatal Period ◽  
Combined Treatment ◽  
Female Rats ◽  
Male Rats ◽  
Normal Male ◽  
Oestradiol Benzoate ◽  
The Brain ◽  
Copulatory Behaviour

Adult male rats which had been castrated at birth and treated with the non-aromatizable androgen dihydrotestosterone propionate (DHTP) showed incomplete copulatory behaviour. When tested with oestrous female rats during treatment with testosterone propionate (TP) they readily mounted these females and showed frequent penile intromissions but rarely ejaculated. In a long series of observations the proportion of ejaculating rats in tests of 30 min did not exceed 50%. Neonatally castrated rats treated with DHTP during infancy thus seemed to be capable of ejaculation in adulthood during treatment with TP, but the threshold for the occurrence of the ejaculatory reflex seemed to be higher than in normal male rats. By replacing treatment in adulthood with TP by a combined treatment with DHTP and oestradiol benzoate (OB), the frequency of ejaculation was not increased. It was concluded that the incomplete copulatory behaviour was not due to reduced efficiency of aromatization of androgen within the brain of these rats. The addition of OB to DHTP during the neonatal period of treatment enhanced the frequency of ejaculation in adulthood. The combined treatment of 0·1 mg DHTP on days 1, 3 and 5 with 0·01 mg OB on day 1 made adult copulatory behaviour during treatment with TP indistinguishable from that of rats castrated on day 10 or rats castrated at birth and treated with TP during infancy. It was concluded that the masculine organization of systems and structures involved in the display of male copulatory behaviour occurs under the influence of both non-aromatizable androgen and oestrogen, oestrogen being most likely the substance required to 'organize' the central nervous aspects of the regulation of this behaviour. The absence neonatally of nonaromatizable androgen and/or oestrogen results in specific deficiencies in adult copulatory behaviour as compared with the behaviour of normal male rats.

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