TESTOSTERONE AND OESTRADIOL SUPPRESSION OF LH AND FSH IN ADULT MALE RATS: DURATION OF CASTRATION, DURATION OF TREATMENT AND COMBINED TREATMENT

1973 ◽  
Vol 73 (1) ◽  
pp. 11-21 ◽  
Author(s):  
R. S. Swerdloff ◽  
P. C. Walsh
Keyword(s):  
Adult Male ◽  
Testosterone Propionate ◽  
Combined Treatment ◽  
Male Rats ◽  
Low Doses ◽  
Duration Of Treatment ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Hypothalamic Pituitary Axis ◽  
Androgen Effect

ABSTRACT The effects of androgens and oestrogens on serum LH and FSH in castrated rats were evaluated with regard to the modifying influences of duration of castration, duration of treatment and combined oestrogen-androgen effect. Serum LH was not greatly influenced by these variables. In contrast, serum FSH was shown to be more resistant to suppression by both steroids after at least five days of castration, requiring a longer duration of treatment to be suppressed to intact levels. Combined treatment of submaximally suppressive doses of testosterone propionate and oestradiol benzoate resulted in no additive effect on lowering serum FSH. Low doses of both androgens and oestrogens resulted in elevated levels of serum LH and FSH, suggesting that the adult male hypothalamic-pituitary axis may be responsive to positive feedback. In all studies, testosterone preferentially suppressed serum LH as compared to serum FSH. In contrast, oestradiol administration produced parallel inhibition of both LH and FSH. It is emphasized that neither oestrogen nor androgen alone, nor in combination, resulted in preferential inhibition of serum FSH over LH.

EFFECTS OF TESTOSTERONE PROPIONATE, 5α-DIHYDROTESTOSTERONE PROPIONATE AND OESTRADIOL BENZOATE ON SERUM LEVELS OF LH AND FSH IN THE CASTRATED ADULT MALE RAT

1974 ◽  
Vol 77 (4) ◽  
pp. 643-654 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes ◽  
J. H. Aafjes ◽  
F. J. M. Vels ◽  
H. J. van der Molen
Keyword(s):  
Adult Male ◽  
Testosterone Propionate ◽  
Serum Levels ◽  
Seminal Vesicles ◽  
Male Rats ◽  
Male Rat ◽  
Low Doses ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Adult Male Rat

ABSTRACT The influence of treatment with various doses of testosterone propionate, 5α-dihydrotestosterone propionate or oestradiol benzoate on serum levels of LH and FSH (measured by radioimmunoassay) and on weights of ventral prostates and seminal vesicles was investigated in castrated, adult, male rats. For depression of the high, castrate levels of serum gonadotrophins with either of these steroid esters, the inhibition curves were different for LH and for FSH. Serum LH was kept at levels encountered in intact, adult, male rats by lower doses of steroid ester than was serum FSH. Oestradiol benzoate was the most potent suppressor of the serum gonadotrophins among the steroid esters tested, testosterone propionate the least. Treatment with low doses of oestradiol benzoate, however, resulted in serum FSH levels significantly above those of castrates treated with vehicle only. Finally, administration of a synthetic LH-releasing factor to testosterone propionate, 5α-dihydrotestosterone propionate or oestradiol benzoate treated, castrated, adult, male rats resulted in a further release of both LH and FSH. The latter effect was more pronounced in oestradiol benzoate treated castrates than in testosterone propionate or 5α-dihydrotestosterone propionate treated castrates.

Reproductive toxicity of DDT in adult male rats

2001 ◽  
Vol 20 (8) ◽  
pp. 393-397 ◽  
Author(s):  
K Ben Rhouma ◽  
O Tébourbi ◽  
R Krichah ◽  
M Sakly
Keyword(s):  
Adult Male ◽  
Pesticide Exposure ◽  
Reproductive Toxicity ◽  
Male Rats ◽  
Male Rat ◽  
Seminiferous Tubules ◽  
Serum Lh ◽  
Testicular Weight ◽  
Hypothalamic Pituitary Axis ◽  
Dose Dependent

The reproductive toxicity of DDT was investigated in adult male rats exposed to 50 and 100 mg/kg body weight (b.wt) day 1 for 10 successive days. Compared with control animals, administration of DDT led to a dose-dependent reduction of testicular weight and the number as well as the percentage of motile spermatozoa in the epididymis. Testicular histological observationsrevealed alsoamarkedloss of gametes in the lumen of seminiferous tubules. In DDT treated rats, the seminal vesicles weights dropped significantly, resulting from a decrease of testosterone production by testes, whereas serum LH and FSH increased after pesticide exposure. This increase of gonadotrophin levels may be related to an impairment of the negative feedback exerted by the steroid on the hypothalamic–pituitary axis. It is concluded that DDT induced adverse effects on male rat fertility by acting directly on the testes and altering the neuroendocrinefunction.

SERUM LH AND FSH LEVELS FOLLOWING INTRAVENOUS INJECTION OF A GONADOTROPHIN RELEASING PRINCIPLE IN NORMAL AND GONADECTOMIZED ADULT MALE RATS TREATED WITH OESTRADIOL-17β OR 5α-DIHYDROTESTOSTERONE

1976 ◽  
Vol 83 (3) ◽  
pp. 493-505 ◽  
Author(s):  
H. L. Verjans ◽  
K. B. Eik-Nes
Keyword(s):  
Intravenous Injection ◽  
Adult Male ◽  
Response Pattern ◽  
Sesame Oil ◽  
Male Rats ◽  
Intact Control ◽  
Serum Lh ◽  
Hypothalamic Pituitary Axis ◽  
Pre Treatment ◽  
Higher Doses

ABSTRACT Effect of intravenous administration of a synthetic gonadotrophin releasing factor (GnRF) on circulating LH and FSH concentrations was investigated in normal and gonadectomized, adult male rats injected subcutaneously each day during seven days with various doses of oestradiol-17β or 5α-dihydrotestosterone in sesame oil. Higher increase in serum LH and FSH levels subsequent to intravenously administered GnRF was observed in castrated control animals than in intact control animals, though this increment was not of significant nature for serum FSH. Pre-treatment of normal and gonadectomized rats with oestradiol-17β resulted in an augmented response of serum LH and FSH concentrations to GnRF iv. Pre-treatment of normal and gonadectomized rats with 5α-dihydrotestosterone diminished serum LH and FSH response following administration of the same amount of GnRF. For these steroids to affect the response pattern of serum LH and FSH to GnRF iv, higher doses were required in normal than in gonadectomized animals. The data indicate that oestrogen and androgen may act at different sites in the male hypothalamic-pituitary axis with respect to regulation of pituitary gonadotrophins.

Testosterone metabolites do not participate in the control of hypothalamic LH-releasing hormone

1986 ◽  
Vol 109 (2) ◽  
pp. 291-296 ◽  
Author(s):  
M. Zanisi ◽  
F. Celotti ◽  
P. Ferraboschi ◽  
M. Motta
Keyword(s):  
Testosterone Propionate ◽  
Male Rats ◽  
Free Form ◽  
Releasing Hormone ◽  
Specific Radioimmunoassay ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Testosterone Metabolites ◽  
Lh Releasing Hormone

ABSTRACT To determine whether the ability of testosterone to increase intrahypothalamic LH-releasing hormone (LHRH) in orchidectomized rats might be explained by the conversion of the hormone into either its 5α-reduced or oestrogenic metabolites, testosterone, 5α-androstan-17β-ol-3-one (DHT), 5α-androstane-3α, 17β-diol (3α-diol) and 5α-androstane-3β,17β-diol (3β-diol) (2 mg/rat per day for 6 days) and oestradiol (0·1, 0·5, 1·0 and 5·0 μg/rat per day for 6 days) were injected into castrated male rats. After 6 days the rats were killed and serum LH levels and intrahypothalamic LHRH stores measured using specific radioimmunoassay procedures. Testosterone and its 5α-reduced metabolites were used in either the free alcohol or the propionate form (dipropionates in the case of the diols); oestradiol was used as oestradiol-17β or in the benzoate form. Treatment with testosterone, DHT, 3α-diol and 3β-diol resulted in a significant decrease in serum LH levels; all the 5α-reduced testosterone derivatives were more effective than testosterone in this respect. Testosterone and DHT propionates suppressed LH release following orchidectomy totally; 3α-diol and 3β-diol dipropionates were less effective. Testosterone increased intrahypothalamic LHRH stores, this effect being much higher after testosterone propionate, i.e. when intrahypothalamic LHRH stores were restored to pre-castration levels. None of the 5α-reduced steroids was capable of modifying the low intrahypothalamic levels of LHRH found following orchidectomy; only 3α-diol dipropionate exhibited some activity, but this was much lower than that of testosterone propionate. Oestradiol-17β was totally ineffective in decreasing serum LH in orchidectomized animals; in contrast, oestradiol benzoate progressively decreased serum LH. Oestradiol in the free form was unable to increase LHRH stores, as was oestradiol benzoate except at the highest dose. The results suggest that the effect exerted by testosterone on hypothalamic LHRH is due to the hormone as such and does not involve its conversion into either 5α-reduced or oestrogenic metabolites. J. Endocr. (1986) 109, 291–296

The in-vitro transformation of [3H]dehydroepiandrosterone into its principal metabolites in the adrenal cortex of adult castrated male rats and following steroid treatment

1989 ◽  
Vol 121 (3) ◽  
pp. 419-424 ◽  
Author(s):  
M. Canonaco ◽  
S. Andò ◽  
A. Valenti ◽  
R. Tavolaro ◽  
M. L. Panno ◽  
...  
Keyword(s):  
Adrenal Gland ◽  
Adult Male ◽  
Testosterone Propionate ◽  
Reductase Activity ◽  
Male Rats ◽  
Adrenal Androgen ◽  
Oestradiol Benzoate ◽  
Rat Adrenals ◽  
Low Testosterone

ABSTRACT The adrenal gland of castrated adult male rats metabolized [3H]dehydroepiandrosterone in vitro to Δ4-androsten-3,17-dione (4AD), testosterone, dihydrotestosterone (DHT) and 5α-androstane-3,17-dione (5αAD). Despite the low testosterone values, DHT and 5αAD were higher 30 and especially 60 days after castration, with raised 4AD:testosterone and decreased testosterone:DHT ratios. The 5α-reductase activity thus appears to increase with time after castration. Fourteen days after castration, 4AD was the only metabolite that was raised compared with intact animals, and testosterone was comparable in sham-operated and castrated rats. The administration of testosterone propionate to castrated rats restored testosterone values to those of intact rat adrenals, whereas 4AD values were greater. The administration of dihydrotestosterone propionate also yielded higher levels of 4AD, in the presence of a lower testosterone value. After administration of oestradiol benzoate, 4AD values were lower especially compared with the other hormone-treated groups, and there was an unexpectedly high testosterone value. These data indicate that the adrenal gland contributes to the production of androgens, as previously noted by Andò, Canonaco, Beraldi et al. (1988) who showed increased plasma 4AD and testosterone levels in adult male rats 30 days after castration. Furthermore, adrenal androgen production in castrated animals is differentially regulated by sex steroids. Journal of Endocrinology (1989) 121, 419–424

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.

scholarly journals Altered sexual differentiation of hepatic uridine diphosphate glucuronyltransferase by neonatal hormone treatment in rats

1979 ◽  
Vol 180 (2) ◽  
pp. 313-318 ◽  
Author(s):  
Coral A. Lamartiniere ◽  
Cindy S. Dieringer ◽  
Etsuko Kita ◽  
George W. Lucier
Keyword(s):  
Enzyme Activity ◽  
Adult Male ◽  
Sexual Differentiation ◽  
Reproductive Tract ◽  
Testosterone Propionate ◽  
Hormone Treatment ◽  
Male Rats ◽  
Ventral Prostate ◽  
Uridine Diphosphate ◽  
Neonatal Administration

The hepatic microsomal enzyme UDP-glucuronyltransferase undergoes a complex developmental pattern in which enzyme activity is first detectable on the 18th day of gestation in rats. Prepubertal activities are similar for males and females. However, postpubertal sexual differentiation of enzyme activity occurs in which male activities are twice those of females. Neonatal administration of testosterone propionate or diethylstilboestrol to intact animals resulted in lowered UDP-glucuronyltransferase activity in liver microsomal fractions of adult male rats, whereas no changes were observed in the adult females and prepubertal male and female animals. Neonatal administration of testosterone propionate and diethylstilboestrol adversely affected male reproductive-tract development as evidenced by decreased weights of testes, seminal vesicles and ventral prostate. Diethylstilboestrol also markedly decreased spermatogenesis. Hypophysectomy of adult male rats resulted in negative modulation of microsomal UDP-glucuronyltransferase and prevented the sexual differentiation of enzyme activity. In contrast hypophysectomy had no effect on female UDP-glucuronyltransferase activity. A pituitary transplant under the kidney capsule was not capable of reversing the enzyme effects of hypophysectomy, therefore suggesting that the male pituitary factor(s) responsible for positive modulation of UDP-glucuronyltransferase might be under hypothalamic control in the form of a releasing factor. Neonatal testosterone propionate and diethylstilboestrol administration apparently interfered with the normal sequence of postpubertal UDP-glucuronyltransferase sexual differentiation.

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).

Mechanism delineating differential effect of an antiestrogen, tamoxifen, on the serum LH and FSH in adult male rats

2006 ◽  
Vol 29 (6) ◽  
pp. 485-496 ◽  
Author(s):  
N. Balasinor ◽  
P. Parte ◽  
M. K. Gill-Sharma ◽  
J. Kini ◽  
H. S. Juneja
Keyword(s):  
Adult Male ◽  
Differential Effect ◽  
Male Rats ◽  
Serum Lh

EFFECTS OF 17β-HYDROXY-4-ANDROSTEN-19-OL-3-ONE (19-HYDROXYTESTOSTERONE) AND 5α-ANDROSTAN-17β-OL-3-ONE (DIHYDROTESTOSTERONE) ON ASPECTS OF SEXUAL BEHAVIOUR IN CASTRATED MALE RATS

1974 ◽  
Vol 61 (1) ◽  
pp. 105-115 ◽  
Author(s):  
R. F. PARROTT
Keyword(s):  
Adult Male ◽  
Sexual Behaviour ◽  
Testosterone Propionate ◽  
Male Rats ◽  
Organ Weights ◽  
Refractory Periods ◽  
Peripheral Effect ◽  
Rate Of Decline ◽  
The Brain ◽  
Experienced Adult

SUMMARY The ability of 19-hydroxytestosterone propionate (150 μg/day) to maintain sexual behaviour, accessory organ weights and the number of penile spines in experienced adult male rats in the 5 weeks after castration was compared with intact males and castrated animals receiving testosterone propionate (75 μg/day) or oil treatment. In a second experiment a group of male rats receiving dihydrotestosterone propionate (150 μg/day) was also included. 19-Hydroxytestosterone did not maintain ejaculatory performance but animals that ejaculated had refractory periods similar to those in intact and testosterone-treated groups. Dihydrotestosterone, however, slowed the rate of decline of ejaculatory performance but the refractory periods were comparable to those in castrated controls. The former action of dihydrotestosterone was attributed to its stimulatory effect on peripheral structures, especially the penile spines. 19-Hydroxytestosterone was shown to have no peripheral effect at doses up to 1800 μg every other day. The results are discussed in terms of a theory of testosterone action involving aromatization in the brain and 5α-reduction peripherally.

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