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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
Steroids 1978 Jun
PMID:In vitro metabolism of androgens by mammalian cauda epididymal spermatozoa. 15 59

Spermatozoa obtained from the cauda epididymidis possess twice the ability to take up sterol sulfates in vitro when compared to sermatozoa obtained from the caput. This would suggest that a modification of the membrane composition of the spermatozoa occurs during passage through the epididymis. Free sterols are taken up in a similar pattern. Radioautographic studies reveal that, for sterol sulfates, this uptake occurs selectively in the regions of the head and mid-piece of the spermatozoa whereas the free sterols are distributed evenly throughout the length of the spermatozoa. The binding of sterol sulfates to spermatozoa appears to involve sites that are unsaturable. The possibility exists that sterol sulfates, previously implicated in membrane stabilization, may play a similar role in spermatozoa.
Steroids 1979 Jul
PMID:The binding of sterol sulfates to hamster spermatozoa. 48 38

The epididymis of adult rats metabolizes 3H 5alpha-androstane-3alpah,17beta-diol (3alpha-diol) by experiments in vitro. After incubation of tissue slices at 37 degrees C for 2 hours, 2% of the radioactivity was found in the water-soluble fraction whereas 98% was found to be ether soluble (free steroids). Further investigation of the free steroids showed the following to be present: 3alpha-diol 39.9%, DHT (17beta-hydroxy-5alpha-androstan-3-one) 33.7%, androsterone (3alpha-hydroxy-5alpha-androstan-17-one) 9.2%, 3beta-diol (5alpha-androstane-3beta,17beta-diol) 2.6%, 5alpha-A-dione (5alpha-androstan-3,17-dione) 1.1%, delta 16-3alpha-ol (5alpha-androst-16-en-3alpha-ol) 1.0%, delta16-3beta-ol (5alpha-androst-16-en-3beta-ol) 2.6%, delta 16-3-one (5alpha-androst-16-en-3-one) 2.9%, and polar compounds 3.3%. When segments of the epididymis (caput and cauda) were incubated in the same way, qualitatively similar metabolites were formed but a greater amount of 3alpha-diol was metabolized by the cauda epididymis. This increase was mainly accounted for by an increased formation of delta 16 compounds (14.3% in cauda, 4.3% in caput). This is most probably due to the presence of larger numbers of mature spermatozoa, which, as we have previously shown, form delta16 steroids from 3alpha-diol and DHT (5).
Steroids 1977 Oct
PMID:Androgen metabolism by rat epididymis. Metabolic conversion of 3H 5alpha-androstane-3alpha,17beta-diol, in vitro. 60 59

Spermatozoa from bovine ejaculates and cauda epiditymidis were incubated with either tritiated 17 beta-hydroxy-5 alpha-androstane-3-one (DHT) or 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol). Examination of the medium incubations demonstrated metabolic conversion of both DHT and 3 alpha-diol when these steriods were incubated with ejaculated sperm. In addition to this interconversion, the following metabolities were identified: 5 alpha-androstane-3 beta, 17 beta-diol, (3 beta-diol), androsterone and 5 alpha-androstane-3, 17-dione (5 alpha-A-dione). Incubations with cauda spermatozoa showed similar metabolic patterns. Androgen binding was exhibited by both sperm types. Examination of the washed cauda sperm pellet, following incubations with 3 alpha-diol showed that the incubated steroid was the most abundantly bound. DHT and 5 alpha-androst-16-en-3 alpha-ol (delta 16-3 alpha-ol1 were also detected. The major part of the radioactivity bound in the sperm pellet was identified as DHT when this steroid was used as the substrate; the remaining radioactivity consisted of 3 alpha-diol and delta 16-3 alpha-ol. Investigations of ejaculated sperm pellets gave similar results apart from the additional identification of 5 alpha-androst-16-en-3 one (delta 16-3-one) and 5 alpha-androst-16-en-3 beta-ol (delta 16-3 beta-ol (delta 16-3 beta-ol).
Steroids 1978 Mar
PMID:Uptake and metabolism of androgens by bovine spermatozoa. 66 70

Marked variations in the 3beta-hydroxysterol content of hamster spermatozoa were observed as they progress through the epididymis. Cholesterol is the major sterol of caputal spermatozoa while the concentration of precursors of cholesterol was higher than that of cholesterol in caudal spermatozoa. One of these precursors has been identified as desmosterol. A second sterol has now been identified as 5alpha-cholestra-7,24-dien-3beta-ol by GLC-MS and by NMR. Its concentration is approximately 3-fold higher than that of cholesterol. This 3beta-hydroxysterol is also found in epididymal tissue.
Steroids 1978 Dec
PMID:5alpha-Cholesta-7,24-dien-3beta-ol as a major sterol of the male hamster reproductive tract. 73 99

The ability to form androgen conjugates and the hormone dependency of the conjugating enzymes have been studied in the rat epididymis. Following the in vitro incubation of 3H-testosterone with epididymal slices from intact and castrated rats, the radioactivity recovered was partitioned between water and ether. Examination of the water soluble radioactivity demonstrated the presence of glucuronides and sulfates. The total radioactivity in the conjugate fraction was the same for both intact and castrated animals. However, castrated rats showed a 3-fold increase in the glucuronide fraction with a corresponding decrease in the formation of sulfates. Characterization of the ether soluble radioactivity after solvolysis of the conjugate fraction from castrated animals, showed DHT (17beta-hydroxy-5alpha-androstan-3-one) and 3alpha-diol (5alpha-andro-stane-3alpha, 17beta-diol) to be the main metabolites. After beta-glucuronidase hydrolysis of the same, only 3alpha-diol could be demonstrated at a significant level, although traces of DHT and delta16 compounds were present. Corresponding hydrolysis of the water phase from incubation of epididymis from intact rats, demonstrated a marked quantitative difference. Here approximately 40% of the conjugated aglycones consisted of delta16 compounds, whilst only about 12% was comprised of 3alpha-diol. The preferential conjugation of DHT and 3alpha-diol to a sulfate radical was demonstrated in both intact and castrated rats. Since the conjugated delta16 compounds were detected only in the epididymis from intact animals, it is possible that these are formed by the spermatozoa.
Steroids 1976 May
PMID:Androgen metabolism by rat epididymis. 4. The formation of conjugates. 94 Nov 82

Cholesteryl sulfate is a component of human seminal plasma (avg. 445 mug%) and spermatozoa (15 mug/10 (9) cells) and represents more than 85% of the sterol sulfate fraction. This conjugate is avidly bound by spermatozoa when compared to other steroids or steroid sulfates. Autoradiographic localization of CS associated with the spermatozoa revealed a greater accumulation of the radioactivity in the acrosomal region in many, but not all, of those cells examined. Semen is not a site of metabolism of the sterol sulfate but the enzyme, sterol sulfatase, is present in the human female reproductive tract. This cleavage enzyme was detected in Graafian follicles and the activity in the endometrium was ten-fold that found in the Fallopian tube. These findings lead to the proposal that cholesteryl sulfate, an amphipathic molecule ideally suited for interaction with membrane components and implicated in erythrocyte membrane stabilization, may be involved in membrane modifications of the spermatozoa during the process of fertilization.
Steroids 1976 Feb
PMID:Cholesteryl sulfate and sterol sulfatase in the human reproductive tract. 127 89

Metabolism of testosterone and estradiol by primary spermatocytes, spermatids and spermatozoa of 6 fertile men, 6 men infertile due to immobile sperm, 8 men who had vasovasostomy, and 11 men who had vasoepididymostomy because of obstruction, was studies by thin layer chromatography. Germ cells were collected at 3-month intervals after surgery, and separated by Percoll gradients. Results were reported as percentages of total counts in substrates and products. Germ cells of normal and post-operative subjects converted testosterone primarily to androstenedione, and their spermatids also formed dihydrotestosterone and androstanediols. Spermatozoa and spermatids also formed estrone from estradiol. Spermatozoa from infertile men primarily produced dihydrotestosterone from testosterone.
Steroids 1991 Oct
PMID:Steroid metabolism by germ cells and spermatozoa in men after vasoepididymostomy. 180 55

Freshly ejaculated spermatozoa from monkey and human were washed and incubated with tritium labelled androgens or estradiol to study the pattern of spermatozoa steroid metabolism. When equal concentrations of steroid substrates were used for incubation, monkey and human spermatozoa showed very similar pattern of steroid conversion. Spermatozoa from both species converted testosterone mainly to androstenedione, but reverse conversion of androstenedione to testosterone was negligible. Estradiol-17 beta was converted mainly to estrone. The close similarity between the spermatozoa of monkey and men in their steroid metabolic pattern indicates that the rhesus monkey could be an useful animal model to study the effect of drugs on the metabolic pattern of human spermatozoa.
Steroids 1983 May
PMID:Steroid metabolism by monkey and human spermatozoa. 665 92

Progesterone can initiate the mammalian sperm acrosome reaction in vitro, and studies on the effect of progesterone and several other steroids have demonstrated an increased calcium influx following binding to the sperm membrane. We have previously presented data indicating the presence of a GABA transport protein in human spermatozoa. In this study, we have examined the uptake of radiolabelled GABA into human spermatozoa in the presence of progesterone, other steroids known to elevate intracellular calcium, and steroids known to be ineffective as stimulators of calcium influx. The results demonstrate a twofold increase in GABA uptake following preincubation with progesterone or steroids known to stimulate calcium influx. Steroids with minor effects on calcium influx were less effective as stimulators of GABA uptake.
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PMID:Progesterone stimulates GABA uptake in human spermatozoa. 880 96


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