SOME ANTIGONADOTROPHIC EFFECTS OF MELATONIN-FREE BOVINE PINEAL EXTRACTS IN RATS

1974 ◽  
Vol 76 (3) ◽  
pp. 438-448 ◽  
Author(s):  
Richard J. Orts ◽  
Bryant Benson ◽  
Byron F. Cook
Keyword(s):  
Gel Filtration ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Reproductive Parameters ◽  
Castrate Male ◽  
Serum Luteinizing Hormone ◽  
Bovine Pineal Extracts ◽  
Modifying Effect ◽  
Pineal Extracts

ABSTRACT Studies were made to determine if a substance other than melatonin was present in bovine pineal gland extracts which possessed properties inhibitory to some gonadotrophin-dependent reproductive parameters in rats. Bovine pineal extracts were partially purified by organic solvent extraction or by ultrafiltration and gel-filtration to exclude melatonin. When administered to rats, the extracts inhibited compensatory ovarian hypertrophy, delayed vaginal opening time and reduced the incidence of constant oestrus. Either of the melatonin-free extracts reduced significantly the concentration of serum luteinizing hormone (LH) in long-term castrate male rats. The data suggest that some substance other than melatonin present in bovine pineal glands has a modifying effect on the reproductive parameters observed probably due to its inhibitory effect on LH.

scholarly journals Dietary ascorbic acid lowers the concentration of soluble copper in the small intestinal lumen of rats

1994 ◽  
Vol 71 (5) ◽  
pp. 701-707 ◽  
Author(s):  
G. J. Van Den Berg ◽  
S. YU ◽  
A. G. Lemmens ◽  
A. C. Beynen
Keyword(s):  
Ascorbic Acid ◽  
Small Intestine ◽  
Liquid Phase ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Intestinal Lumen ◽  
Distal Intestine ◽  
Small Intestinal ◽  
Ascorbic Acid Supplementation

We tested the hypothesis that ascorbic acid in the diet of rats lowers the concentration of soluble Cu in the small intestine, causing a decrease in apparent Cu absorption. Male rats were fed on diets adequate in Cu (5 mg Cu/kg) without or with 10 g ascorbic acid/kg. The diet with ascorbic acid was fed for either 6 or 42 d. Ascorbic acid depressed tissue Cu concentrations after a feeding period of 42, but not after 6 d. Dietary ascorbic acid lowered apparent Cu absorption after 6, but not after 42 d. The lowering of tissue Cu concentrations after long-term ascorbic acid feeding may have increased the efficiency of Cu absorption, and thus counteracted the inhibitory effect of ascorbic acid. Dietary ascorbic acid caused a significant decrease in the Cu concentrations in the liquid phase of both the proximal and distal parts of the small intestinal lumen. This effect was due to both a decrease in the amount of Cu in the liquid digesta and an increase in the volume of the liquid phase; only the latter effect for the distal intestine was statistically significant. We conclude that ascorbic acid supplementation lowers Cu absorption by decreasing the concentration of soluble Cu in the small intestine.

ANTIFERTILITY PROPERTIES OF BOVINE PINEAL EXTRACTS: REDUCTION OF OVULATION AND PRE-OVULATORY LUTEINIZING HORMONE IN THE RAT

1977 ◽  
Vol 85 (2) ◽  
pp. 225-234 ◽  
Author(s):  
R. J. Orts ◽  
K. M. Kocan ◽  
R. P. Johnson
Keyword(s):  
Luteinizing Hormone ◽  
Female Rats ◽  
Low Molecular Weight ◽  
Moderate Reduction ◽  
Serum Lh ◽  
Bovine Pineal Extracts ◽  
Modifying Effect ◽  
The Mean ◽  
Pineal Extracts ◽  
Lh Secretion

ABSTRACT Bovine pineal glands were extracted with acetic acid and partially purified on Sephadex G-25. Three fractions, F3, F4 and F5, were each administered to cycling female rats for 4, 2 or 1 day prior to ovulation to determine their effects on fertility, ovulation and the pro-oestrous surge of luteinizing hormone (LH). The incidence of pregnancy and the mean number of foetuses were reduced in animals after treatment with F3 or F4 but not in those treated with F5. Each of the F3 and F4 fractions significantly reduced the mean number of ova shed and the pre-ovulatory concentration of serum LH. The F5 fraction caused a moderate reduction of the pro-oestrous rise of serum LH but had no significant effect on ovulation. The data suggest that fertility in rats can be reduced by more than one substance of low molecular weight present in bovine pineal extracts through a modifying effect on LH secretion and subsequent ovulation.

Decreased tolerance to ethanol-induced hypothermia in long-term castrate male rats

1993 ◽  
Vol 46 (2) ◽  
pp. 309-314 ◽  
Author(s):  
Robert F. McGivern ◽  
Ted Melcer ◽  
Christine L. Melchior
Keyword(s):  
Male Rats ◽  
Induced Hypothermia ◽  
Castrate Male ◽  
Tolerance To Ethanol

scholarly journals Lead and iron absorption from rat small intestine: the effect of dietary Fe deficiency

1978 ◽  
Vol 40 (2) ◽  
pp. 253-260 ◽  
Author(s):  
I. K. Robertson ◽  
M. Worwood
Keyword(s):  
Small Intestine ◽  
Rat Liver ◽  
Ferrous Sulphate ◽  
Gel Filtration ◽  
Male Rats ◽  
Adult Rat ◽  
Iron Deficient ◽  
Liver Ferritin ◽  
The Relationship

1. When lead is administered in drinking-water iron-deficient rats retain more Pb than Fe-replete rats (Six & Goyer, 1972; Klauder & Petering, 1975). In the present study the relationship between the absorption of Pb and Fe was investigated.2. Adult male rats were transferred to a milk-based diet fed with or without supplementary Fe (180 mg Fe/kg as ferrous sulphate). After 7–9 d the absorption of duodenally-administered203Pb and59Fe was measured as uptake of radioactivity from the gastrointestinal tract after 90 min.59Fe absorption was increased in rats given the unsupplemented diet for 7 d and was further increased in rats kept on the diet for up to 7 weeks.203Pb absorption was not consistently increased by either short- or long-term Fe deprivation.3. Much of the203Pb in homogenates of the upper small intestine was bound to soluble protein of which up to 85% was dialysable. In contrast little59Fe was dialysable. Only a small proportion of the soluble musosal Pb was associated with ferritin during gel-filtration chromatography although203Pb precipitated together with carrier rat-liver ferritin with an antibody to rat-liver ferritin.4. There appeared to be no direct relationship between the transfer of Fe and Pb across the small intestine of the adult rat.

EFFECT OF CYPROTERONE ACETATE ON ANDROGEN-DEPENDENT SYNTHESIS OF α2u GLOBULIN IN RATS

1976 ◽  
Vol 70 (2) ◽  
pp. 189-195 ◽  
Author(s):  
A. K. ROY
Keyword(s):  
Cyproterone Acetate ◽  
Inhibitory Effect ◽  
Term Treatment ◽  
Mature Male ◽  
Male Rats ◽  
Male Rat ◽  
Long Term Treatment ◽  
Androgenic Regulation ◽  
Primary Induction

SUMMARY Cyproterone acetate (CA, 2·5 mg/100 g body wt) inhibited androgenic induction of α2u globulin in spayed rats. In mature male rats, which normally produce α2u globulin, ten daily injections of CA did not inhibit synthesis of this protein. Long-term treatment of mature male rats (two injections every week for 12 weeks) showed only slight inhibition of α2u synthesis after 10 weeks of CA treatment. CA also failed to compete with 5α-dihydrotestosterone for the cytosol androgen-binding protein of male rat liver. The inhibitory effect of CA on the primary induction of α2u globulin in the spayed rat and its lack of effect on continued synthesis of this protein in maximally induced mature male rats are consistent with the hypothesis of a two-step mechanism for androgenic regulation of α2u synthesis, an initial CA-sensitive step followed later by a CA-insensitive step.

Perinatal exposure to insecticide fipronil: effects on the reproductive system in male rats

2017 ◽  
Vol 29 (6) ◽  
pp. 1130 ◽  
Author(s):  
Aline L. de Barros ◽  
Julie H. Bae ◽  
Cibele S. Borges ◽  
Josiane L. Rosa ◽  
Marilia M. Cavariani ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Sperm Quality ◽  
Expression Patterns ◽  
Male Rats ◽  
Perinatal Exposure ◽  
Reproductive Parameters ◽  
Sperm Production ◽  
Long Term Effects ◽  
Pregnant Rats

Fipronil is an insecticide widely used in agriculture, veterinary medicine and public health that has recently been listed as a potential endocrine disrupter. In the present study we evaluated the effects of perinatal exposure to fipronil during the period of sexual brain differentiation and its later repercussions on reproductive parameters in male rats. Pregnant rats were exposed (via gavage) to fipronil (0.03, 0.3 or 3 mg kg–1) from Gestational Day 15 until Postnatal Day 7. Fipronil exposure did not compromise the onset of puberty. In adulthood, there was no effect on organ weight or sperm production. Furthermore, there were no adverse effects on the number of Sertoli cells per seminiferous tubule, testicular and epididymal histomorphometry or histopathology or expression patterns of androgen receptor in the testis. Similarly, no changes were observed in the sexual behaviour or hormone levels. However, in rats exposed to fipronil, changes in sperm motility were observed, with a decrease in motile spermatozoa and an increase in non-mobile spermatozoa, which can compromise sperm quality in these rats. Perinatal exposure to fipronil has long-term effects on sperm parameters, and the epididymis can be a target organ. Additional studies should be undertaken to identify the mechanisms by which fipronil affects sperm motility.

Perinatal exposure to parasiticide ivermectin: long-term effects on reproductive parameters of adult male rats

2011 ◽  
Vol 93 (2) ◽  
pp. 345-351
Author(s):  
Eduardo Wladimir Avilés Terneux ◽  
Davi Abeid Pontes ◽  
Carla Dal Bianco Fernandez ◽  
Arielle Cristina Arena ◽  
Elaine Manoela Porto ◽  
...  
Keyword(s):  
Adult Male ◽  
Male Rats ◽  
Perinatal Exposure ◽  
Reproductive Parameters ◽  
Long Term Effects

EFFECT OF ADRENALECTOMY OR CASTRATION ON THE INHIBITION OF GONADOTROPHIN SECRETION INDUCED BY HYPERPROLACTINAEMIA IN THE ADULT MALE RAT

1980 ◽  
Vol 85 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. S. McNEILLY ◽  
R. M. SHARPE ◽  
H. M. FRASER
Keyword(s):  
Adult Male ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Male Rat ◽  
Gonadotrophin Secretion ◽  
Adult Male Rat ◽  
Pituitary Glands ◽  
Lh Rh ◽  
Lh Releasing Hormone

SUMMARY To investigate the role of adrenal and gonadal steroids in the long-term suppression of gonadotrophin secretion induced by prolactin the effects of adrenalectomy or castration on the serum and pituitary levels of LH, FSH and prolactin and the hypothalamic content of LH releasing hormone (LH-RH) have been studied in adult male rats with hyper prolactinaemia produced by the transplantation of pituitary glands under the kidney capsule. Levels of LH and FSH in serum were significantly suppressed in all intact pituitary-grafted rats. Adrenalectomy on the day of pituitary implantation or 20 days later did not affect this suppression. However, castration on days 0,28 or 49 after pituitary grafting resulted in a rise in levels of FSH in serum indistinguishable from that in control rats. While the rise in levels of LH after castration on day 0 was the same as the controls, this increase was significantly reduced 2 days after castration on days 28 and 49 after pituitary grafting. Castration resulted in an increase in the pituitary content of LH and a reduction in the hypothalamic content of LH-RH but no change in the pituitary content of FSH. Hyperprolactinaemia did not appear to affect these responses. The present results showed clearly that the gonad but not the adrenal must be present for prolactin to exert an inhibitory effect on gonadotrophin secretion.

Effects of oestradiol benzoate (OeB) and human chorionic gonadotrophin (hCG) on the testes and accessory sex glands of the rat

1981 ◽  
Vol 96 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Mridula Chowdhury ◽  
Robert Tcholakian ◽  
Emil Steinberger
Keyword(s):  
Treated Group ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Control Group ◽  
Intact Male ◽  
Intact Control ◽  
Testosterone Levels ◽  
Oestradiol Benzoate ◽  
Direct Inhibitory Effect

Abstract. It has been suggested that treatment of intact male rats with oestradiol benzoate (OeB) causes an interference with testosterone (T) production by the testes by a direct inhibitory effect on steroidogenesis. To test this hypothesis, different doses (5, 10 or 25 IU) of hCG were administered concomitantly with 50 μg of OeB to adult intact or hypophysectomized male rats. The testicular and plasma testosterone, and serum hCG levels were determined. The sex accessory weights were recorded. In the intact OeB-treated group of animals, hCG stimulated both the secondary sex organs and plasma testosterone levels above the intact control group. However, in hypophysectomized animals, although plasma testosterone levels increased above that of intact controls, their secondary sex organ weights did not. Moreover, inspite of high circulating hCG levels, the testicular testosterone content and concentration remained suppressed in OeB-treated animals. The reason for such dichotomy of hCG action on OeB-treated animals is not clear at present.

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