PubMed Health⌕ Search

Biomedical subjects

A Pousette

Publications and source records attributed to A Pousette.

132 records · Page 8Linked to original sources
PubMed1974

Different mechanisms of regulation of nuclear reduced nicotinamide-adenine dinucleotide phosphate-dependent 3-oxo steroid 5alpha-reductase activity in rat liver, kidney and prostate.

The regulatory mechanisms involved in the control of the nuclear NADPH-dependent 3-ketosteroid 5alpha-reductase (5alpha-reductase) activity were studied in liver, kidney and prostate. The substrate used was [1,2-(3)H]androst-4-ene-3,17-dione (androstenedione) (for liver and kidney) or [4-(14)C]androstenedione (for prostate). The hepatic nuclear 5alpha-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 5alpha-reductase. The renal nuclear metabolism of androstenedione, i.e. 5alpha reduction and 17beta-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 5alpha-reductase activity and a significant decrease in the 17beta-hydroxy steroid reductase activity. Finally, the nuclear 5alpha-reductase activity in prostate was androgen-dependent, decreasing after castration and increasing after treatment with testosterone propionate. In conclusion, the nuclear 5alpha-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 5alpha-reductase participates in the formation of a physiologically active androgen, 5alpha-dihydrotestosterone, this may not be the true function of the nuclear 5alpha-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. 5alpha-androstane-3,17-dione and/or 5alpha-dihydrotestosterone).

Journal Article↗
PubMedDate not supplied

Hormone levels in male ice hockey players during the night after a 26-hour cup tournament.

Pituitary hormones, adrenal and testicular steroids and steroid-binding proteins were analysed in 4 active ice hockey players and in 3 spectators, matched for physical fitness, during the night after a 26-hour cup tournament. The examined period included the last match of three matches. Unconjugated adrenal steroids (cortisol, 4-androstene-3,17-dione [A-4] and dehydroepiandrosterone [DHA]) and prolactin were increased in players immediately following the match, but were normalized within 3-4 h. After that similar nocturnal patterns were observed in players and spectators. The time-courses for DHA sulphate, albumin and sex hormone binding globulin (SHBG) were identical in players and spectators. Serum testosterone (T), 17 alpha-hydroxyprogesterone (17OHP) and LH levels had time-courses with a nadir between 20.00 and 24.00 h and maximum values in the morning; however, this pattern was less pronounced in players. The results illustrate the rapid normalization of adrenocortical activity after physical stress and further support the view that interference with pituitary LH secretion may be the main mechanism responsible for the observed changes in testicular steroids.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Morphology of seminal and swim-up spermatozoa and the outcome of in vitro fertilization and embryo transfer.

Tubal infertility was treated by in vitro fertilization-embryo transfer (IVF-ET) in 112 couples. Twenty-eight pregnancies were obtained in 140 treatment cycles. Couples are accepted for treatment in our IVF-ET programme if previous semen samples fulfil the inclusion criteria: ejaculate volume greater than 1.5 ml, concentration of spermatozoa greater than 15 x 10(6) ml-1, greater than 40% motile spermatozoa, and greater than 25% spermatozoa with normal morphology. In order to determine to which extent IVF-ET treatment results are influenced by sperm morphology, within this selected group of patients, we have retrospectively analysed the data from both original semen samples and swim-up preparations. The sperm morphology was not related to the outcome of treatment in terms of fertilization (ovum cleavage rate), early embryo development, or pregnancy. Nor was any relationship detected between early embryo development or pregnancy and the degree of improvement in morphology resulting from the swim-up procedure. However, if improvement in morphology by swim-up was high, ovum cleavage rate was low. Sperm morphology within the limits set by our inclusion criteria could not predict the outcome of IVF-ET treatment. It is further concluded that the presence of abnormal spermatozoa at the site of fertilization may be without harm if only the number of normal sperms is high enough.

Embryo Transfer↗