Sex steroid levels and Leydig cell ultrastructure of the male common sheath-tail bat, Taphozous georgianus

1989 ◽  
Vol 1 (1) ◽  
pp. 47 ◽  
Author(s):  
SE Jolly ◽  
AW Blackshaw
Keyword(s):  
Leydig Cell ◽  
Seasonal Changes ◽  
Smooth Endoplasmic Reticulum ◽  
Cell Ultrastructure ◽  
Accessory Gland ◽  
Plasma Testosterone ◽  
Reproductive Pattern ◽  
Testosterone Levels ◽  
Accessory Glands ◽  
The Face

Male sheath-tail bats were collected from central Queensland over a 12-month period. Plasma testosterone levels peaked in August, coincident with an increase in the volume of the accessory glands and ampulla/seminal vesicle secretion. Peak spermatogenesis occurred in summer and autumn and declined in the face of maximal testosterone levels in winter. Levels of androstenedione and 5 alpha-dihydrotestosterone were high compared with testosterone levels and showed no significant seasonal changes. Ultrastructural examination of Leydig cell cytoplasm revealed numerous lipid droplets and mitochondria, and an abundant smooth endoplasmic reticulum. There were no seasonal changes in Leydig cell ultrastructure. The anomalous reproductive pattern in this species is consistent with the imposition of a cold-induced winter spermatogenic shutdown, on a framework of continuous spermatogenesis, with spring peaks in testosterone and accessory gland activity.

scholarly journals Evaluation of endocrine testing of Leydig cell function using extractive and recombinant human chorionic gonadotropin and different doses of recombinant human LH in normal men

2008 ◽  
Vol 159 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Anne Cailleux-Bounacer ◽  
Yves Reznik ◽  
Bruno Cauliez ◽  
Jean François Menard ◽  
Céline Duparc ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Leydig Cell ◽  
Cell Function ◽  
Dose Effect ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Plasma Estradiol ◽  
Normal Men ◽  
Dose Dependent ◽  
Leydig Cell Function

BackgroundThe functional testing of endocrine testis uses extractive human chorionic gonadotropin (ehCG). Recombinant human hCG (rhCG), avoiding any contamination, should replace ehCG. Moreover, a functional evaluation with recombinant human LH (rhLH) would be closer to physiology than a pharmacological testing with hCG.MethodsThe study was conducted in normal men. We first evaluated the dose–effect of ehCG on plasma testosterone and estradiol levels, before and after injection of either hCG or vehicle. Secondly, the responses to the optimal dose of ehCG were compared with those of rhCG. Thirdly, we investigated the dose–effect of rhLH, on steroid hormone secretion. LH, testosterone, and estradiol plasma levels were measured after the injection of either rhLH or placebo.ResultsehCG induced dose-dependent increases in plasma estradiol and testosterone levels. They respectively peaked at 24 and 72 h after the injection. The most potent dose of ehCG (5000 IU) induced results similar to those observed with 250 μg (6500 IU) rhCG. By comparison with placebo, rhLH induced a significant and dose-dependent increase in plasma testosterone levels 4 h after the injection. Peak response of testosterone to rhLH and rhCG was significantly correlated. rhLH did not induce significant change in plasma estradiol level.ConclusionsIn normal men, a single i.v. injection of 150 IU rhLH induces a 25% rise in plasma testosterone levels by comparison with placebo. At the moment, the dynamic evaluation using hCG remains the gold standard test to explore the Leydig cell function. The use of 250 μg rhCG avoiding any contamination should be recommended.

A transplantable rat Leydig cell tumour.

1988 ◽  
Vol 119 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Aa. Erichsen ◽  
O. P. F. Clausen ◽  
P. Torjesen ◽  
E. Dahl ◽  
P. Wetteland ◽  
...  
Keyword(s):  
Leydig Cell ◽  
Tumour Growth ◽  
Tumour Size ◽  
Pituitary Hormones ◽  
Cell Tumour ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Leydig Cell Tumour ◽  
Hypophysectomized Rats ◽  
Tumour Weight

Abstract. Growth rate and morphology were studied in a transplantable rat Leydig cell tumour (H-540) grown in intact, castrated and hypophysectomized rats. The plasma levels of pituitary hormones and testosterone were measured in the same rats. The results can be summarized as follows: 1. The growth curves of tumours in intact and castrated rats were S-shaped and very similar during the observation period of three weeks. 2. In hypophysectomized rats, the onset and progression of tumour growth were delayed, compared with intact and castrated rats. 3. The thymidine labelling index as well as the size of the S and G2 phase compartments were decreased in tumours greater than 10 g compared with smaller tumours and tumours grown in hypophysectomized rats. 4. Testosterone concentrations in plasma correlate well with increasing tumour weight up to approximately 10–15 g in intact and castrated rats. 5. Plasma testosterone levels in tumour-bearing hypophysectomized rats were 7-fold higher than those of corresponding intact and castrated rats. 6. In castrated rats, suppression of LH production occurs by very small tumours (< 2 g), whereas FSH levels show a gradual decrease with increasing tumour size. PRL production was independent of castration, tumour weight, and testosterone levels. 7. In spite of no major differences in cell morphology, the morphometric analysis revealed a reduction in tumour cell size and nuclear size in hypophysectomized rats compared with intact and castrated rats. It is concluded that pituitary hormones stimulate tumour growth, but surprisingly appear to reduce the secretion of testosterone from these tumours.

ENDOCRINE TESTICULAR FUNCTION IN VIVO AND IN VITRO IN INFERTILE MEN

1979 ◽  
Vol 90 (3) ◽  
pp. 544-551 ◽  
Author(s):  
E. Nieschlag ◽  
E. J. Wickings ◽  
J. Mauss
Keyword(s):  
Leydig Cell ◽  
Cell Function ◽  
Testicular Tissue ◽  
Plasma Testosterone ◽  
Cell Hyperplasia ◽  
Testosterone Levels ◽  
Infertile Men ◽  
Before And After

ABSTRACT In order to detect any possible Leydig cell dysfunction associated with male infertility, the endocrine capacity of the testes was investigated in vivo and in vitro in 21 infertile men. Plasma testosterone was determined before and after 3 days of hCG stimulation. Testicular tissue obtained by bilateral biopsies was subjected to (1) histological examination, (2) determination of basal testosterone concentration and (3) incubation with hCG. Patients were grouped according to histology. In vitro basal and stimulated testicular testosterone was similar in patients with normal histology, Sertoli-cell-only syndrome and spermatogenic arrest. Tissue from patients with Leydig cell hyperplasia showed 3-fold higher basal testosterone levels and a greater response to hCG. All patients had plasma testosterone levels and responses to hCG in the normal range. There was no significant correlation between the data obtained in vivo and in vitro, indicating that testosterone determinations in peripheral blood do not necessarily reflect the intratesticular situation. There was no evidence for gross abnormality in Leydig cell function accompanying disturbed spermatogenesis.

Seasonal changes in plasma testosterone concentration and mating activity in Border Leicester, Poll Dorset, Romney and Suffolk rams

1983 ◽  
Vol 23 (122) ◽  
pp. 248 ◽  
Author(s):  
MJ D'Occhio ◽  
DE Brooks
Keyword(s):  
Seasonal Changes ◽  
Extended Period ◽  
Field Conditions ◽  
Plasma Testosterone ◽  
Real Relationship ◽  
Mating Activity ◽  
Testosterone Concentration ◽  
Testosterone Levels ◽  
Seasonal Peak ◽  
Precise Time

Seasonal changes in the plasma testosterone profile and mating activity were compared for Border Leicester, Poll Dorset, Romney and Suffolk rams (three of each breed) maintained under field conditions at latitude 35�S. Border Leicester, Romney and Suffolk showed maximum testosterone levels from February to May. Peak mating activity occurred from March to August, but the precise time and duration of the peak differed between the three breeds. A correlation (r = 0.65, P<0 .05) existed between seasonal changes in plasma testosterone and mating activity in Border Leicester but not in Romney or Suffolk. However, in all three breeds, peak testosterone levels preceded peak mating activity by 1-2 months. Poll Dorset rams showed an extended period of high testosterone levels from August to March but no seasonal peak in mating activity. There was no real relationship, in any breed, between plasma testosterone concentration and mating activity for individual rams within any month.

Seasonal variation in the plasma testosterone concentration of reindeer and caribou

1973 ◽  
Vol 51 (6) ◽  
pp. 651-658 ◽  
Author(s):  
P. E. Whitehead ◽  
E. H. McEwan
Keyword(s):  
Seasonal Variation ◽  
Growth Pattern ◽  
Seasonal Changes ◽  
Seasonal Pattern ◽  
Plasma Testosterone ◽  
Endocrine Glands ◽  
Testosterone Concentration ◽  
Testosterone Levels ◽  
Rhythmic Growth ◽  
Two Hybrid

Plasma testosterone levels of reindeer increased from 1 ng/cm3 in August to 30–60 ng/cm3 in mid-September. By late October, when rutting activity had almost ceased, the testosterone concentration had declined to barely detectable levels. The seasonal pattern exhibited by caribou was similar except the peak levels associated with rutting occurred about 1 month later than reindeer. The seasonal changes in plasma testosterone levels of two hybrid calves were studied. Peak testosterone levels of 5 and 3.8 ng/cm3 were attained in late October.The influence of the endocrine glands on antler renewal and casting, and the rhythmic growth pattern exhibited by caribou and reindeer are discussed.

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