Testosterone production by rabbit testis slices

Connell, Gerald M.; Eik‐Nes, Kristen B.

doi:10.1016/s0039-128x(68)80114-x

Cited by 40 publications

(5 citation statements)

References 11 publications

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“…The finding of FSH positive cells among Leydig cells may bear on the findings that FSH acts synergistically on LH-mediated testosterone synthesis in the testis (10)(11)(12) and that FSH increases the number of LH receptors per Leydig cell and Leydig cell sensitivity to LH stimulation (13)(14)(15). Whereas the main target of FSH action is the tubules, administration of FSH antiserum decreased the plasma testosterone levels in rhesus monkeys, suggesting an influence of FSH on the Leydig cell function (35).…”

Section: Jce and M • 1983 Vol57«no4mentioning

confidence: 86%

“…In the rat, FSH specifically binds to seminiferous tubules but not to other tissues or isolated Leydig cells (4). FSH appears to act synergistically with LH on the Leydig cells and permits a higher rate of testosterone synthesis (10)(11)(12). It also increases the number of LH receptors on the Leydig cells and Leydig cell sensitivity to LH stimulation (13)(14)(15).…”

mentioning

confidence: 99%

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Localization of Luteinizing Hormone, Follicle-Stimulating Hormone, Prolactin, and Their Receptors in Human and Rat Testis Using Immunohistochemistry and Radioreceptor Assay*

Wahlström

Huhtaniemi

Hovatta

et al. 1983

The Journal of Clinical Endocrinology & Metabolism

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Immunoperoxidase staining and radioreceptor assay were used to study the localization of LH, FSH, and PRL and their receptors in the human and rat testis. In immunohistochemical staining, the Leydig cells of both species were invariably LH positive and generally FSH negative, but there were some FSH positive cells which were morphologically indistinguishable from the Leydig cells. The tubules were LH negative. The Sertoli cells of both species were FSH positive, whereas the spermatogonia and other germ cells were negative. Positive staining for PRL was seen in rat Leydig cells, whereas the human testes were negative. In keeping with the immunohistochemical findings, LH and FSH receptors were found in the testis of both species, but PRL receptors only in the rat. The finding of FSH positive cells in the interstitial tissue may explain why FSH increases the number of Leydig cell LH receptors and increases the sensitivity and maximum response to LH stimulation. Failure to demonstrate PRL and PRL receptors in the human testis indicates either that very low receptor concentrations are needed to bring about PRL action or that the established testicular effects of PRL are indirect.

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Section: Jce and M • 1983 Vol57«no4mentioning

confidence: 86%

mentioning

confidence: 99%

Localization of Luteinizing Hormone, Follicle-Stimulating Hormone, Prolactin, and Their Receptors in Human and Rat Testis Using Immunohistochemistry and Radioreceptor Assay*

Wahlström

Huhtaniemi

Hovatta

et al. 1983

The Journal of Clinical Endocrinology & Metabolism

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“…The methanolic solutions were utilized as follows: a) 200 /xl were removed for liquid scintillation counting to determine the total radioactivity present in each sample, b) 400 /il were acetylated according to the (12) or Connell and Eik-Nes (13). Reaction products were then chromatographed in an unsaturated system of benzene-ethylacetate (8:2, vol/vol).…”

Section: Isolation Identification and Estimation Of Reaction Productsmentioning

confidence: 99%

Progesterone Metabolism in Normal Human Endometrium During the Menstrual Cycle and in Endometrial Carcinoma

Pollow

Lübbert

Boquoi

et al. 1975

The Journal of Clinical Endocrinology & Metabolism

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Different subcellular fractions (purity checked by electron microscopy and respective marker enzymes) were incubated with 0.1 muCi 14C-progesterone (10 muM) in 0.15 M phosphate buffer at pH 7.4 and 37 C under air for varying periods of time in the presence of NAD(P)H (500 muM). By the preparation of chromic acid oxidation products and acetates, thin-layer chromatography, and crystallisation to constant specific activity, the following metabolites were identified: 20alpha-hydroxypregn-4-en-3-one, 20alpha-hydroxy-5alpha-pregnan-3-one, 20alpha-hydroxy-5beta-pregnan-3-one, 5alpha-pregnane-3,20-dione, and 5beta-pregnane-3,20-dione, indicating the presence of a 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) and 5alpha- and 5beta-reductases. Most of the 20alpha-HSD activity was located in mitochondria (associated mainly with outer membranes) and microsomes. Purified nuclei and cytosol contained 1/6 to 1/18 of the activity of mitochondria and microsomes, respectively. SUBFRACTIONS OF ENDOMETRIAL CELLS ONLY CONTAINED EITHER 5ALPHA- OR 5BETA-REDUCTASE ACTIVITY. 5alpha-reductase activity was mainly associated with microsomes, 5beta-reductase activity was found only in the cytosol. While in normal endometrium specific enzyme activities in subcellular fractions depended on the phase of the cycle, in endometrial carcinoma it depended on the degree of tumour differentiation. The highest values of 5alpha-reductase activity were found in the early proliferative phase. 20alpha-HSD activity was highest in the middle of the secretory phase. The specific activity of the 5alpha-reductase increased with decreasing differentiation of the tumour while the specific activity of the 20alpha-HSD decreased. Kinetic parameters (Km-values, coenzyme requirements and maximum velocities) were determined. The Km-value for progesterone of the 20alpha-HSD in proliferative endometrium was significantly higher than in secretory endometrium, while the Km-values of the 5alpha- and 5beta-reductases were considerably lower during the proliferative than secretory phase.

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“…It has been suggested that nicotines act as a central nervous system stimulant and also interferes with endocrine secretion of gonadotropins (FSH and LH) and prolactin from the pituitary and causes a feedback decrease in testosterone level [27,28]. Nicotine has been reported to have a dose-dependent deleterious effect on the sperm characteristics.…”

Section: Resultsmentioning

confidence: 99%

Effect of Smokeless Tobacco Product, Afzal, on the Reproductive Hormones and Gonadal Pathology of Wistar Rats

Al-Mukhaini

Omar

Eltayeb

et al. 2020

SQU Journal for Science

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Afzal is a common smokeless tobacco product (STP) in Oman, and it is believed to contain toxins that may affect the reproductive hormones and hence reproductive function. This study assessed the effect of Afzal on the gonads of Wistar rats. In order to assess gonad toxicity induced by this STP, an aqueous extract of Afzal was added to drinking water to be administrated orally to Wistar albino rats (n = 72) classified as young (4 weeks old) and adult (20 weeks old) of both genders weighing between 60-80 g and 150-240 g respectively for 8 weeks. The rats were divided into 3 groups; control (received distilled water instead of Afzal extract), low-dose (received 3 mg nicotine/kg body weight/day) and high-dose (received 6 mg nicotine/kg body weight/day). At the termination of the study, the rats were euthanized and their blood samples and ovaries were collected for biochemical and histopathological investigations. Testosterone and estradiol hormones showed a significant decrease (P<0.05( in Afzal-treated groups (low and high doses) compared with the control. Histopathological findings revealed the damaging effects manifested as a reduction in the number of the germ cells with deformed organization and in fatty and fibrous degenerations in testes and ovaries. Afzal was found to have adverse effect on the reproductive hormones and gonadal pathology in Wistar rats of both genders, and hence users of Afzal need to consider the risk associated with its frequent use.

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Testosterone production by rabbit testis slices

Cited by 40 publications

References 11 publications

Localization of Luteinizing Hormone, Follicle-Stimulating Hormone, Prolactin, and Their Receptors in Human and Rat Testis Using Immunohistochemistry and Radioreceptor Assay*

Localization of Luteinizing Hormone, Follicle-Stimulating Hormone, Prolactin, and Their Receptors in Human and Rat Testis Using Immunohistochemistry and Radioreceptor Assay*

Progesterone Metabolism in Normal Human Endometrium During the Menstrual Cycle and in Endometrial Carcinoma

Effect of Smokeless Tobacco Product, Afzal, on the Reproductive Hormones and Gonadal Pathology of Wistar Rats

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