Correlation between ultrastructure and biochemical changes in the testis of the American grey squirrel, Sciurus carolinensis, during the reproductive cycle

Pudney, Jeffrey; Lacy, Dennis

doi:10.1530/jrf.0.0490005

Cited by 31 publications

(13 citation statements)

References 18 publications

(21 reference statements)

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“…Only in Miniopterus, apparently, do the accessory glands invo lute over winter. The present study has confirmed the category II pattern of Leydig cell and accessory gland activity in Miniopterus demonstrating involuted second ary sex glands in association with low steroid synthetic Leydig cell support [as expressed by the abundance of lipid: Christensen, 1975: Neaves, 1975: Pudney and Lacy, 1977 throughout much of the year. A similar ultrastruc tural profile has been described for regressed Leydig cells in Myotis lucifugus fWimsatt andParks.…”

Section: Discussionsupporting

confidence: 82%

Reproductive Biology of the Male Bent-Winged Bat, <i>Miniopterus schreibersii</i> (Vespertilionidae) in Southeast South Australia

Krutzsch¹,

Crichton²

1990

Cells Tissues Organs

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The seasonal chronology of the events of the reproductive cycle, and changes in the structure and function of the primary and accessory organs of the male bent-winged bat Miniopterus schreibersii, were studied at latitude 37° S in temperate southeastern Australia. The testicular cycle commenced in late spring (November), and sperm appeared in the seminiferous tubules and epididymides in early fall (March). The cycle of the accessory sex gland complex generally paralleled the testicular cycle, reaching maximum hypertrophy at the time of insemination in late fall (April/May). Thereafter, the primary and secondary sex glands (except the ampullary gland) involuted as the animals entered winter torpor. However, a cauda epididymidal store of sperm persisted until late spring, and sperm were often observed, as well, in the ampullary gland duct and alveoli throughout winter. This study has confirmed that male Miniopterus differs from other vespertilionids in that accessory gland activity declines following the fall breeding in keeping with the fact that unlike in other vespertilionids insemination ovulation and conception are concurrent events in the fall in this species. The reduced secretory status of the Leydig cells and exceptionally low levels of circulating androgens throughout the year, in combination with the presence of viable epididymidal sperm for most of gestation, are all interesting features of this reproductive cycle.

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Section: Discussionsupporting

confidence: 82%

Reproductive Biology of the Male Bent-Winged Bat, <i>Miniopterus schreibersii</i> (Vespertilionidae) in Southeast South Australia

Krutzsch¹,

Crichton²

1990

Cells Tissues Organs

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“…At the testicular level the reduced 20a-hydroxysteroid dehydrogenase activity is probably due to the decrease in the relative volume of tubular tissue in relation to interstitial tissue in the regressed testis, since this enzyme is considered to reside mostly in the tubular compartment (van der Molen & Rommerts, 1981). Pudney & Lacy (1977) studied seasonal changes in the in-vitro metabolism of radiolabelled pregnenolone and progesterone in interstitial and tubular tissue isolated from the testes of the grey squirrel (Sciurus carolinensis) and found a decrease in the activity of 17a-hydroxylase and C17_20 lyase in both testicular compartments and an increase in the 20a-hydroxysteroid dehydrogenase activity in the interstitium of the regressed testis.…”

Section: Discussionmentioning

confidence: 99%

“…These studies are also not necessarily comparable, since the material of Pudney & Lacy (1977) consisted of animals that had attained sexual maturity before seasonal regression. It has been proposed that 20a-hydroxysteroid dehydrogenase could regulate androgen synthesis by competing with 17a-hydroxylase and C, 7_20 lyase for common substrates as well as by producing 20a-dihydropregnenolone, 20a-dihydroprogesterone and 17a-hydroxy,20a-dihydroprogesterone which are known inhibitors of 17a-hydroxylase and C17_20 lyase in the human and rat testis (Shikita & Tamaoki, 1965: Fan, Oshima, Troen & Troen, 1974Hosaka, Oshima & Troen, 1980).…”

Section: Discussionmentioning

confidence: 99%

Photoperiod-induced changes in the testicular metabolism of [14-14C]17 -hydroxyprogesterone in the bank vole (Clethrionomys glareolus)

Teräväinen¹,

Tähkä²

1985

Reproduction

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Summary. Minces of the testes of bank voles, born and reared in a long (18L:6D) photoperiod until weaning (18\p=n-\22days of age) and subjected thereafter to a short (6L: 18D, Group S) or a long (18L:6D, Group L) photoperiod for 6\p=n-\9weeks, were incubated with [4-14C]17\g=a\-hydroxyprogesterone in the presence of cofactors (NADP/ NADPH, 1\m=.\3 mmol/l) for 1 h at 37\s=deg\C.The radioactive metabolites were characterized and identified by thin-layer chromatography with derivative formation and chromatography to constant specific activity and isotope ratio. In Group L virtually all of the substrate was utilized and it was readily converted to androgens (48% of the radioactivity recovered) such as androstenedione and testosterone. The only pregnane metabolite identified was 17\g=a\-hydroxy,20\g=a\-dihydroxyprogesterone(43\m=.\3%). In Group S there was a decreased production of 1 7 \ g = a \ -h y d r o x y , 2 0 \ g = a \ -d i h y d r o p r o g e s t e r o n e and androgens (25\m=.\4% and 10\m=.\4%respectively) and a substantial portion of the substrate was not metabolized (38\m=.\8%). The main androgen metabolites identified, androst-4\x=req-\ ene-3\g=b\,17\g=b\-diol and 5\g=a\-androstane-3,17-dione are hormonally quite inert steroids. No androstenedione or testosterone was found. The results indicate that exposure to short photoperiod induces a decrease in the testicular C17-C20 lyase and 20\g=a\-hydroxysteroid dehydrogenase.

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“…The occurence of reduced agranular reticulum has been correlated with a reduction in androgen synthesis as observed in rock hyrax and grey squirrel (Neaves, 1973;Pudney and Lacy, 1977).…”

Section: Testismentioning

confidence: 94%

Ultrastructural changes in Leydig cells and cauda epididymal spermatozoa induced byAzadirachta indica leaves in albino rats

Aladakatti¹,

Ahamed²

2005

Phytother. Res.

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The effects of Azadirachta indica leaves (500 mg/kg body weight, orally/day), testosterone (0.25 mg/kg body weight/day, intramuscularly) and a combination of these two were investigated as to whether Azadirachta indica leaves affect the morphology of Leydig cells and epididymal sperm and their organelles at the ultrastructural level. Azadirachta indica treated rats showed atrophic seminiferous tubules with widening intercellular spaces. Leydig cells exhibited characteristics of degeneration such as indented nuclei; the commencement of degeneration was evident from less chromatin; the reduced amount of a marked decrease in organelle content and scarcity of other cell types of the interstitium in highly vacuolated cytoplasm, which were seem from both light and electron microscopic observations. The number of Leydig cells and their nuclear diameter were reduced significantly. Pathological changes in the spermatozoa of the cauda epididymis were observed and the spermatozoa retained cytoplasmic droplets. It is suggested that regression of Leydig cells and the absence of interstitium cell types indicates an androgen deficiency, which affects the spermatozoa in the epididymis by disturbing the internal epididymal milieu. The antiandrogenic and antispermatogenic properties of Azadirachta indica leaves appear to lead to a reduced fertilizing ability of the sperm.

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Correlation between ultrastructure and biochemical changes in the testis of the American grey squirrel, Sciurus carolinensis, during the reproductive cycle

Cited by 31 publications

References 18 publications

Reproductive Biology of the Male Bent-Winged Bat, <i>Miniopterus schreibersii</i> (Vespertilionidae) in Southeast South Australia

Reproductive Biology of the Male Bent-Winged Bat, <i>Miniopterus schreibersii</i> (Vespertilionidae) in Southeast South Australia

Photoperiod-induced changes in the testicular metabolism of [14-14C]17 -hydroxyprogesterone in the bank vole (Clethrionomys glareolus)

Ultrastructural changes in Leydig cells and cauda epididymal spermatozoa induced byAzadirachta indica leaves in albino rats

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