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Biomedical subjects

A Demoulin

Publications and source records attributed to A Demoulin.

84 records · Page 5Linked to original sources
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[Male infertility].

In 2/3 of infertility problems, the male partner is, partially or entirely, responsible. His investigation starts with a careful history and is followed by a thorough physical examination. Then, comes the spermogram. In addition to an assessment of the number, motility, and morphology of spermatozoids, this examination must involve a spermocytogram, tests of anti-spermatozoid immunity, and a bacteriological analysis. The biological study of the seminal plasma is also of considerable value. Electron microscopy of sperm is valuable in asthenospermic men. A genetic and hormonal investigation is, nowadays, almost mandatory in all cases. Testicular biopsy with cryopreservation of testicular tissue and demonstration of a possible varicocele can also, in selected cases, be of great help. The overall strategy will be decided on the basis of the whole investigation.

Humans↗
PubMedDate not supplied

Prolactin (PRL) inhibiting substance in seminal plasma of infertile patients. Preliminary results.

The role of PRL in the control of the mechanisms of regulation of testicular function is still unclear. Indeed, hyperprolactinemia is usually associated with male hypofertility. Several studies have demonstrated that human seminal plasma (HSP) contains radioimmunoassayble PRL and than testis and prostate possess membrane receptors for PRL (Charreau et al. 1977; Aragona et al. 1977). Recently Demoulin and Franchimont have observed, in HSP, the presence of a substance capable of inhibiting PRL secretion by isolated rat pituitary cells (Demoulin et al. 1978). They abbreviated it SPIF (seminal plasma PRL inhibiting factor). The inhibition of PRL secretion was significant for concentrations equal to or higher than 4.2 l of HSP/ml of culture medium. This non steroidal substance is thermostable and trypsin resistant; the molecular weight is less than 10,000 Daltons. In this work, we have compared the SPIF activity with basal levels of LH, FSH, PRL, Testosterone and, after stimulation, in the serum of patients affected with various fertility problems.

Adult↗
PubMedDate not supplied

Influence of Danazol on gonadotropin secretion and synthesis by rat pituitary cells in cultures. Comparison with gonadal steroids.

Increasing concentrations of estradiol, testosterone, progesterone (1.10(-10) to 1.10(-7] and Danazol (1.10(-9) to 1.10(-6) M) have been added to male rat pituitary cells maintained in monolayer cultures for a preincubation period of three days followed by a six hour incubation with or without GnRH (1.10(-8) M). Concentrations of LH and FSH have been assessed in the culture media and in the cells at the end of the experiments allowing an estimation of the influence of these steroids on gonadotropin release and synthesis. In these experimental conditions, estradiol does not modify basal and GnRH induced FSH release and synthesis but reduces the GnRH-induced response of LH. Testosterone and progesterone stimulate synthesis of FSH but inhibit synthesis and secretion of LH in the presence of GnRH. These results have been compared with those of literature. Danazol, in the same experimental conditions, stimulates synthesis of gonadotropins and simultaneously inhibits their release induced by the presence of GnRH. We conclude that Danazol is able to act at the pituitary level as testosterone which is in good agreement with its androgenic properties.

Animals↗
PubMedDate not supplied

[Inhibin: new gonadal hormone (author's transl)].

There are many convincing arguments to accept the existence of inhibin. This hormone is produced inside the seminiferous tubules by the Sertoli cells in males and by the granulosa cells of the follicule in females. The biological, immunological and chemical characteristics of testicular and ovarian inhibin are identical so that it could be speculated the same molecule is secreted by both organs. This hormone is not a knownsteroid but is a protein substance. Thus, its biological activity is destroyed by trypsin and pepsin digestion and by heating at 60 degrees for 30 minutes. Furthermore, immunization with inhibin from rete testis fluid induces antibodies capable of neutralizing endogenous inhibin of adult male and female rats. This polypeptide hormone is not identical neither to ABP nor to a fragment of gonadotrophins. The molecular weight is not yet exactly defined and the possibility exists that two forms of inhibin are present in RTF: one of high (greater than 10,000 Daltons) and the other of low molecular weight. The high M.W. species could be a polymer or alternatively the combination of native inhibin and a carrier substance or unique precursor molecule. Inhibin preparations selectively depress the synthesis and the release of FSH in pituitary cell culture. The threshold dose to affect the LH production is higher than that active on FSH secretion. Furthermore, they reduce LH-RH content of hypothalamus maintained in organ culture. In animals, inhibin induced effects are depending on both hypothalamus and pituitary actions according to the functions of these two structures. In that sense, apparently contradictory results are obtained in short and long term castrated animals. Inhibin does not modify TSH, GH and prolactin in vivo and in vitro. This substance displays an inhibition on the synthesis of DNA in the testis of pubertal male rats and depresses the maturation of follicle in female.

Animals↗
PubMedDate not supplied

[Origin and sites of action of inhibin (author's transl)].

Mice testis in organ culture (31 degrees C) produce a steroid free substance which inhibits FSH secretion by rat pituitary cells. Histologically, Sterloti cells alone remain normal after a few days in culture. A hypothalamic action of inhibin is demonstrated in vitro. The intraglandular content in LHRH is inversely related to the amount of inhibin present in the culture medium. In the testis, DNA synthesis is depended of inhibin. This is demonstrated by studies of the incorporation of tritiated thymidine in testicular DNA in vivo and in vitro. In conclusion, inhibin is produced by Sertoli cells and acts not only at this pituitary level but also on the hypothalamus and the testis.

Animals↗