COMPARISON OF THE EFFECT OF NEONATAL ADMINISTRATION OF TESTOSTERONE AND DIHYDROTESTOSTERONE IN THE FEMALE RAT

SUMMARY Groups of neonatal female rats were treated once daily for the first 5 days of life with oil, 1 μg testosterone propionate, or 10 μg of one of the following androgens; androstenedione-enol-propionate, 19-hydroxytestosterone propionate, 5α-dihydrotestosterone propionate, 5α-androstanedioneenol-propionate, androsterone propionate, 5α,3α-androstenediol dipropionate, 5α,3β-androstanediol dipropionate. A final group was given 100 μg 5α,3β-androstanediol dipropionate as a single injection on day 1 of life. Only those androgens which are aromatizable were effective in preventing cyclicity whilst the 5α-reduced androgens were ineffective or only partially effective. All treatments significantly increased the ano-genital distance compared with oil-treated control animals. There were no clear relationships between aromatization and the effects on suppressing sexual behaviour after oestrogen and progesterone treatment. The results are discussed in terms of the role of aromatization in the hormonal control of hypothalamic differentiation.

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Mechanisms for altered reproductive function in female rats following neonatal administration of raloxifene

Acta Endocrinologica ◽

10.1530/eje.0.1500397 ◽

2004 ◽

pp. 397-403 ◽

Cited By ~ 4

Author(s):

M Tena-Sempere ◽

ML Barreiro ◽

E Aguilar ◽

L Pinilla

Keyword(s):

Mrna Expression ◽

Estrogenic Activity ◽

Reproductive Function ◽

Female Rats ◽

Female Rat ◽

Lhrh Agonist ◽

Neonatal Administration ◽

Lh Secretion

OBJECTIVE: Raloxifene is a non-steroidal selective estrogen receptor modulator (SERM) that mimics estrogenic activity on bone density and blood lipid concentration without uterotropic actions. Previous data from our laboratory indicated that, as is the case for estrogen, neonatal administration of raloxifene disturbed normal differentiation of the hypothalamic circuitries governing the gonadotropic axis. In contrast, raloxifene did not act in the same way as estrogen does on the neuronal systems controlling sexual receptivity in the female rat. At present, however, the mechanisms for these organizing effects of raloxifene are not completely elucidated. DESIGN AND METHODS: To analyze this phenomenon, female rats were injected daily with raloxifene (50, 100, 250 or 500 microg/rat per day) between days 1 and 5 of age. On day 23, hypothalamic gonadotropin-releasing hormone (LHRH) mRNA expression was assessed, and pituitary and plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were measured in basal and LHRH-stimulated conditions. In addition, LH and FSH responses to ovariectomy were evaluated in raloxifene-treated females. Finally, we monitored the ability of neonatal administration of a potent LHRH agonist ([d-Ala(6),d-Gly(10)]-LHRH ethylamide; 0.01 microg/kg per 12 h on days 1-5) to counteract the effects of raloxifene. RESULTS: Our analyses demonstrated that prepubertal rats (23-day-old females) treated neonatally with raloxifene showed decreased hypothalamic LHRH mRNA expression levels, reduced pituitary content of LH and FSH, reduced basal and LHRH-stimulated LH secretion in vivo and in vitro, and decreased response to ovariectomy. In addition, adult females treated neonatally with raloxifene showed anovulation and reduced serum LH levels; these effects were not prevented by the simultaneous administration of a LHRH agonist. CONCLUSION: In conclusion, our data demonstrate that neonatal administration of raloxifene can disrupt the programming of hypothalamic-pituitary-ovarian axis function. Reduced LH secretion, under basal and LHRH-stimulated conditions and after ovariectomy, is probably related to decreased LHRH expression, reduced pituitary LH content and/or decreased pituitary responsiveness to hypothalamic LHRH.

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Effects of Hop (Humulus lupulus L.) and Sesame (Sesamum indicum L.) enriched diet on xenobiotic-metabolizing enzymes in female rat livers

Planta Medica ◽

10.1055/s-0028-1083956 ◽

2008 ◽

Vol 74 (09) ◽

Author(s):

H Martin ◽

H Figard-Fabre ◽

N Chernine ◽

A Berthelot ◽

L Richert ◽

...

Keyword(s):

Sesamum Indicum ◽

Humulus Lupulus ◽

Female Rat ◽

Metabolizing Enzymes ◽

Xenobiotic Metabolizing Enzymes ◽

Humulus Lupulus L ◽

Rat Livers

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Novel mechanism of action of a traditional chinese herbal formula in an intact aged female rat model of menopause

Planta Medica ◽

10.1055/s-0035-1556199 ◽

2015 ◽

Vol 81 (11) ◽

Cited By ~ 1

Author(s):

H Ma ◽

Y Lu ◽

D Liu ◽

S Wicks ◽

GB Mahady

Keyword(s):

Mechanism Of Action ◽

Rat Model ◽

Female Rat ◽

Herbal Formula ◽

Chinese Herbal Formula ◽

Chinese Herbal

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OXYDATION DES ANABOLIKUMS 1-METHYL-ANDROST-1-EN-17β-OL-3-ON MIT WASSERSTOFFTRANSFER AUF ÖSTRON

Acta Endocrinologica ◽

10.1530/acta.0.0670517 ◽

1971 ◽

Vol 67 (3) ◽

pp. 517-530 ◽

Cited By ~ 1

Author(s):

Martin Wenzel

Keyword(s):

Rat Liver ◽

Anabolic Steroid ◽

Female Rats ◽

Male Rats ◽

Female Rat ◽

Liver Slices ◽

Androgen Effects ◽

Biochemical Difference

ABSTRACT With the aid of metenolon-17α-T a tritium-transfer to oestrone in rat liver slices was demonstrated. This tritium-transfer from metenolon17α-T to oestrone yielding tritium-labelled oestradiol had a higher efficiency in male than in female rat liver. Correspondingly in the presence of metenolon the relation of oestrone to oestradiol is changed more in male than in female rat liver. Looking for biochemical differences between the anabolic steroid metenolon and testosterone the oxydation at C17 was measured in different organs of the rat using 17α-T-labelled steroids. The highest oxydation rate was found for both steroids in the liver. In the sexual organs of male rats the oxydation rate of testosterone was 50–10 times higher than that of the anabolic steroid. This difference was less in sexual organs of female rats. This result of a greater biochemical difference between both steroids in males than in females leads to the question, whether the dissociation between the anabolic and the androgen effects is higher in males than in females.

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GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

Acta Endocrinologica ◽

10.1530/acta.0.0580600 ◽

1968 ◽

Vol 58 (4) ◽

pp. 600-612 ◽

Cited By ~ 1

Author(s):

Robert Boyd ◽

Donald C. Johnson

Keyword(s):

Ascorbic Acid ◽

Testosterone Propionate ◽

Female Rats ◽

Female Rat ◽

Feedback Effects ◽

Male And Female ◽

Prostate Weight ◽

Male And Female Rats ◽

Males And Females ◽

Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

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