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K. Purvis and V. Hansson

Summary. The levels of testosterone, dihydrotestosterone (DHT), 5α-androstan-3α,17β-diol and androgen-binding protein (ABP) were measured in various segments of the epididymis from adult rats which had been unilaterally orchidectomized for 4 weeks. On the 'intact' side, ABP concentrations were highest in the caput region. The segmental distribution of DHT closely followed that of ABP with the highest concentration in the caput (40 ng/g tissue) and lowest in the cauda (10 ng/g tissue) epididymidis. There was a high degree of correlation (r = 0·98) between the concentration of DHT in the epididymis and ABP levels. 'Castration' completely abolished the DHT gradient. The levels of testosterone and androstanediol were lower than those of DHT; most was present in the corpus epididymidis. The relative differences were reduced after 'castration'. It is concluded that ABP in the rat epididymis is the primary factor for determining the concentration of DHT in the epididymal fluid.

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K. Purvis and I. Egdetveit

Regional differences in the total activities of the epididymal secretory parameter, α-glucosidase, were demonstrated in the 20 000 g supernatants of human epididymal homogenates. A comparison of the enzymic activities in the supernatants and the washings from 12 one centimetre segments of human epididymides indicated an activity peak in segments 3–4 which appeared to be largely intracellular and which presumably reflects the acidic isoenzyme. A second peak in the caudal region, the segmental localization of which was more variable and differed in post-mortem and operation specimens, appeared to be primarily intraluminal. The activities of ornithine decarboxylase (ODC), the rate-limiting enzyme in the polyamine pathway, also exhibited regional differences with higher activities in relatively short segments in both caput and caudal portions. Corresponding alterations were also found in the tissue concentrations of the enzyme products, spermidine and spermine. The increased intracellular activities of ODC and α-glucosidase in the distal caput segments presumably reflect the transition of epithelium from the efferent to the epididymal ducts.

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K. Purvis and N. B. Haynes

Summary. Testosterone levels were significantly higher in males, regardless of sexual experience, exposed to the odour of urine from females than in those exposed to saline or kept in ordinary groups.

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K. J. COOPER, K. PURVIS and N. B. HAYNES

It is established that male proximity can influence the oestrous cycle of the underfed rat even when physical contact between the sexes is prevented; the lengthened cycles characteristic of underfeeding becoming significantly shorter (Cooper & Haynes, 1967; McNeilly, Cooper & Crighton, 1970). More recently, it has been shown that exposure for 15 hr/day to different male rats can elicit a greater and more sustained response from the female than continuous exposure to the same male partner (Purvis, Cooper & Haynes, 1971). This work, however, did not distinguish between two possibilities, namely, whether the stimulating effect of discontinuous association was a result of periodic removal and reintroduction of the stimulus or of regular alteration of the stimulus by the use of different males. The object of the

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K. PURVIS, K. J. COOPER and N. B. HAYNES

Summary.

Continuous pairing of underfed female rats, each with the same male rat under conditions which prevented bodily contact, significantly lowered the frequency of oestrus and increased the number of females which ceased to show cyclic activity when compared to underfed females not exposed to males or to those exposed to different males each day for 15 hr (P<0·01).

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Ø. Magnus, A. Tolefsrud, T. Åbyholm and K. Purvis

Summary. Unwashed human spermatozoa enter columns of 20% albumin in cohorts and not in a continuous stream. Using normospermic ejaculates, a single cohort, representing ∼ 10% of the total number of spermatozoa added, appeared within 1 h of addition. In contrast, when ejaculates from asthenozoospermic men were tested using the same incubation period (1 h), the cohorts contained < 5% of the total. Exposure of ejaculates to 2-deoxyadenosine, a potent stimulator of sperm motility, doubled the number of spermatozoa present in the cohort, but not the average velocity of the group. We suggest that spermatozoa also enter the cervical mucus and pass through the female reproductive tract in cohesive groups.

Keywords: spermatozoa; albumin columns; cohorts; 2-deoxyadenosine; asthenozoospermia; man

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H. Rui, E. Haug, B. Mevåg, Y. Thomassen and K. Purvis

Summary. The effects of a single injection of ovine prolactin on prostatic function were monitored in intact, intact androgenized and castrated-androgenized rats rendered hypoprolactinaemic after 7 days of treatment with a potent dopamine agonist, lisuride. Hypoprolactinaemia was associated with reductions in ventral prostate weight, polyamine levels, lateral lobe zinc and the concentration of the ventral prostate protein prostatein, but an elevation in the level of cytosolic oestradiol binding. Whether these differences attained statistical significance depended on whether the animals were intact, intact-androgenized or castrated-androgenized. With the exception of ventral prostate weight and lateral lobe zinc concentrations, a single injection of prolactin restored or reversed these changes towards control levels within 12 h, which could not be explained by an indirect effect of the hormone on adrenal or testicular function. No effects of lisuride or prolactin were observed with regard to the content of fructose in the coagulating gland or in the degree of prolactin binding to prostatic membranes.

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O. P. F. Clausen, K. Purvis and V. Hansson

Summary. The technique of microflow fluorometry (MFF) was used to identify the proportion of haploid cells (from the tubules) in interstitial cell suspensions. The MFF estimates of the degree of contamination by tubular elements correlated well with the numbers of cells with Leydig cell morphology and those staining positively for 3β-hydroxysteroid dehydrogenase.

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I. J. SHEARER, K. PURVIS, G. JENKIN and N. B. HAYNES

Summary.

A double isotope derivative assay and a simple competitive protein-binding assay were used to measure peripheral plasma progesterone levels during the pig oestrous cycle. In view of the similarity between the results, the more convenient protein-binding method was employed to determine progesterone levels during prepuberty, the oestrous cycle, early and late pregnancy, parturition and lactation. Peripheral plasma oestradiol-17β levels were measured during the oestrous cycle, early pregnancy and around the time of parturition.

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K. Purvis, E. Haug, Y. Thomassen, B. Mevåg and H. Rui

Summary. Mating in the rat was associated with a significant reduction in the tissue concentrations of the presumptive secretory products of the male accessory sex glands: prostatein and the amines, putrescine, spermidine and spermine (ventral prostate lobe), zinc (lateral prostate lobe) and fructose (coagulating gland). The amount of secretory product discharged and the time taken to restore precopulatory levels differed for the different lobes.

Within 12–24 h of the mating period, the activity of ornithine decarboxylase and cytosolic oestrogen binding in the ventral prostate lobe underwent a transient increase which lasted 2–3 days. No change was observed in prolactin binding.

Circulating testosterone concentrations were significantly elevated above control values 12 h after the start of mating but were significantly lower than control values at 24 h. A gradual recovery to concentrations in controls occurred over the next 2–3 days. None of these changes could be explained by alterations in gonadotrophin or prolactin release.