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Biomedical subjects

L Martini

Publications and source records attributed to L Martini.

At least 217 records · Page 12Linked to original sources
PubMed1977

Neuroendocrine effects of a non-steroidal compound of testicular origin.

The effects of the compound (+)-1,4-diphenylbutane-2,3-diol (DPB, synthetized in the testes) on gonadotropin secretion have been studied in castrated male rats. DPB, when injected subcutaneously, does not modify serum levels of LH and FSH. On the contrary, the local implantation of DPB in the median eminence of the hypothalamus results in a significant elevation of serum FSH. It is suggested that DPB may play a physiological role in the control of FSH release.

Animals↗
PubMed1977

Metabolism of testosterone in the anterior pituitary gland and the central nervous system of the European starling (Sturnus vulgaris).

The metabolism of testosterone was studied in vitro in anterior pituitary, hypothalamic and hyperstriatal tissues taken from male European starlings in the autumn. In all the tissues studied, testosterone was converted into 5alpha-androstan-17beta-ol-3-one (5alpha-DHT), 5beta-androstan-17beta-ol-3-one (5beta-DHT), 5beta-androstane-3alpha,17beta-diol (5beta-THT), 5beta-androstane-3,-17-dione and androst-4-ene-3,17-dione. The 5alpha-DHT was produced in significantly greater amounts by the pituitary gland than by the hypothalamus and hyperstriatum. The amount of 5alpha-DHT produced, however, was very low in comparison with the amounts of 5beta-reduced metabolites. The amount of 5beta-reductase was also higher in the pituitary gland than in the two nervous tissues. The ratios between the production of 5beta-DHT, 5beta-THT and 5beta-androstane-3,17-dione were, however, different in the three tissues: 5beta-DHT was produced in the greatest quantities by the hyperstriatum, while the production of 5beta-THT, 5beta-androstane-3,17-dione and androst-4-ene-3,17-dione was greatest in pituitary tissue. The role of 5alpha- and 5beta-reduced metabolites in the pituitary gland and in the brain of birds is unknown, but some possibilities arising from the present results are discussed.

Androstane-3,17-diol↗
PubMed1976

Lack of detectable secretion of ACTH from pituitary homografts of pars intermedia.

Hypophysectomized rats bearing grafts of the pars intermedia (PI) in the kidney capsule for 20 days did not show adrenal weights significantly different from those of hypophysectomized controls. Plasma corticosterone was undetectable in the grafted rats, even after the injection of lysine-vasopressin or histamine. On the other hand, MSH activity was present in measueable amounts, independent of the drug administered, in the plasma of the grafted rats. These results suggest that PI transplants do not have the ability to release ACTH, even though it has been previously reported that they contain this hormone.

Adrenal Glands↗
PubMed1975

Influence of the estrous cycle and prostaglandins on utero-ovarian vein blood flow in the rat.

The blood flow rate in the utero-ovarian vein (UOV) has been measured in adult female rats during the different phases of the estrous cycle. It was observed that the blood flow rate in the UOV is high at proestrus and at estrus and low during diestrus days 1 and 2. The intravenous injection of 10 mug PGF2alpha or PGE2 diminishes the blood flow rate in the UOV. The efficacy of the two PGs in reducing blood flow is different in the various phases of the estrous cycle, being maximal during the day of estrus.

Animals↗
PubMed1975

Anti-implantation effect of prostaglandins in the rat.

PGF2alpha and PGE2 have been instilled in small amounts (5mug) into the uterine horns of pregnant rats at different intervals following mating. Unilateral as well as bilateral injections have been used. Three parameters have been taken into consideration at laparotomy performed on the 13th day of pregnancy: a) the number of implantation sites; b) the number of viable fetuses; and c) the number of corpora lutea present on the ovarian surface. Both PGs proved able to inhibit implantation, to affect the development of embryos and to exert some luteolytic activity when given between D-1 and D-6 of pregnancy.

Animals↗