Superfusion in vitro in the study of ovarian steroidogenesis.

A method for the continuous superfusion of porcine corpus luteum tissue is described which readily allows both the introduction of regulatory factors to the incubating tissue, and sampling of the tissue. Oestrogen (principally oestradiol) and progestin (principally progesterone) can be measured for up to 24 h in the superfusate from corpora lutea of all ages, and the secretion of both steroids is stimulated by the addition of luteinizing hormone. The pattern of response of both steroids to a pulse of gonadotrophin was similar in that a rapid transient increase in secretion occurred followed some time later by a secondary and more prolonged response. A second pulse of gonadotrophin introduced 6 h after the first also stimulated steroid secretion, indicating that during superfusion in vitro the porcine corpus luteum does not become refractory to the steroidogenic effect of gonadotrophin.

Metabolism of testosterone by forehead skin of the roebuck (Capreolus capreolus).

Roebucks have a specialized region of skin on the forehead which contains sebaceous and apocrine glands that produce secretions used in territorial marking. These glands enlarge during the breeding season and regress after the rut as the testes regress. The metabolism of testosterone by this forehead skin in vitro was studied in two captive roebucks over the period of glandular enlargement and subsequent regression, and compared with that of dorsal skin. In May, June and July, both areas of skin actively metabolized testosterone and the metabolites detected were androstenedione, androstanedione, dihydrotestosterone, epiandrosterone, androsterone and 5alpha-androstanediols. There were no major differences in testosterone metabolism between the two body sites, although dorsal skin appeared to be more active in total metabolism than forehead skin. There was a peak in the extent of metabolism in June/July, with a subsequent gradual decline to December. The decline in metabolism occurred at a time when the associated glands were still enlarged, which suggests that the availability of androgen to the skin glands is determined not only by the amount of testosterone in the circulation, but also by a decrease in the metabolizing capacity of the tissue.

Effect of fenoprofen on thyroid function tests.

We observed that a few patients taking the anti-inflammatory drug fenoprofen showed increases in total and free T3 serum levels without convincing evidence of an associated thyrotoxicosis. To confirm these findings, two volunteers were given fenoprofen for two weeks. Within this time total T3 levels almost doubled and free T3 levels increased threefold. Administration of fenoprofen did not have any measurable effect on T4 or TSH estimations. Cross-reactivities of fenoprofen and 4'-hydroxyfenoprofen were studied with antisera from various total and free T3 assays. Results show that the metabolite cross-reacts with the antisera from Amerlex total and free T3 assay kits. A lesser degree of interference was observed with the Corning total and free T3 assays. 4'-hydroxyfenoprofen had no effect on an 'in house' total T3 assay. Laboratories should therefore be aware of the possibility that their assay may be subject to interference by fenoprofen or its metabolites while clinicians should be aware of this interference in order that they may avoid unnecessary and harmful treatment.

In vitro metabolism of androgens by mammalian cauda epididymal spermatozoa.

The in vitro metabolism of [3H] testosterone (17beta-hydroxy-4-androsten-3-one), [3H] androstenedione (4-androstene-3,17-dione) and [3H] dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) by cauda epididymal spermatozoa from the rat, rabbit, hamster, guinea-pig and ram, varied between species. There were differences in the androgens utilized, the extent of their conversion and the identities of the metabolites formed. Of the steroid substrates tested rat spermatozoa metabolized testosterone preferentially while spermatozoa from guinea-pig transformed [3H] dehydroepiandrosterone (DHEA) almost exclusively. Rabbit spermatozoa converted all three [3H] androgens while hamster sperm utilized [3H] testosterone and [3H] DHEA. Spermatozoa collected from rams killed at the abattoir metabolized both [3H] androstenedione and [3H] DHEA but this capacity was dramatically reduced in spermatozoa collected from rams subjected to short-term anaesthesea. The results are discussed in relation to the possible direct roles of androgens in sperm physiology.

In vitro metabolism of (3H)-androstenedione in the rat epididymis and vas deferens.

The in vitro metabolism of (3H)-androstenedione in the epididymis and vas deferens of intact and castrated rats was investigated and the metabolites formed were identified by radio gas chromatography. Incubation of slices of caput epididymidis for 2 hr at 34 degrees C metabolised 90% androstenedione. Similar incubations of tissue samples from cauda epididymidis and vas deferens metabolized 60 and 25% of androstenedione respectively. The major metabolites formed in the epididymis were androstanedione (caput: 48%; cauda: 33%) and androsterone (caput: 35%; cauda: 13%). These metabolites appeared in much less concentration in the incubations with vas deferens (about 8% each). In general, conversion to testosterone and dihydrotesterone was low in all the three organs examined. Castration did not significantly alter the metabolic pattern in the caput epididymidis and vas deferens but promoted the formation of androsterone (38%) in the cauda epididymidis. The conversion of androstenedione, a weak androgen to testosterone, dihydrotestosterone and 3 alpha/3 beta-diols in the epididymidis and vas deferens of castrated rats may be of physiological significance. In addition, androsterone appears to be an important androgenic metabolite in the epididymis.