The action of gonadotropic hormones upon rabbit testis in vitro

Hall, Peter F.; Eik‐Nes, Kristen B.

doi:10.1016/0006-3002(62)90105-1

Cited by 125 publications

(46 citation statements)

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“…That the interstitial cell stimula ting hormone (ICSH) also willpromote de ncvo synthesis of testosterone in vitro (7) and in vivo (10) has been demonstrated by our group. This effect of ICSH on the testicular tissus is specific, since the administration of other pituitary hormones will not affect the secretion of testosterone in vivo (10).…”

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confidence: 92%

“…When large doses of follicle stimulating hormone (FSH) preparations are given to anesthetized dogs, the secretion of testosterone will, however, increase (10). This effect of FSH preparations is also seen in vitro (7). It appears possible that the small amount of ICSH activity found in the FSH preparations** used is unusually potent inpromoting testosterone secretion.…”

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confidence: 97%

“…1), the stimulatory effect of PMS is abo-Kristen B. Eik-Nes lished. De nove synthesis of proteins may therefore be an important aspect in the mechanism of action of the gonadotrophins on the testis in vivo (7). Of considerable interest is the fact that many of the pituitary hormones may promote increased production of enzymatic proteins in order to affect their target cells (13,14,15).…”

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confidence: 99%

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Factors Influencing the Secretion of Testosterone in the Anesthetized Dog

Eik‐Nes

1965

Folia Endocrinol

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Factors Influencing the Secretion of Testosterone in the Anesthetized Dog

Eik‐Nes

1965

Folia Endocrinol

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“…It has been shown that protein synthesis is involved in stimulation by lutropin of testosterone production in rat testis Leydig cells (Hall & Eik-Nes, 1962;Cooke et al, 1975b;Mendelson et al, 1975). After maximal stimulation of testosterone synthesis in rat testis Leydig cells by lutropin, addition of cycloheximide decreases testosterone production to control values.…”

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Regulation of the synthesis of lutropin-induced protein in rat testis Leydig cells

Janszen

Cooke

Driel

et al. 1978

Biochemical Journal

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The mechanism of action of lutropin on the stimulation of the synthesis of a specific lutropin-induced protein in rat testis Leydig cells was investigated. Lutropin-induced protein has a mol.wt. ofapprox. 21000 and is detected by labelling the Leydig-cell proteins with [35S]methionine, followed by separation by polyacrylamide-gel electrophoresis and radioautography of the dried gel. The incorporation of 35S into lutropin-induced protein was used as an estimate for the synthesis of the protein. Incubation of Leydig cells with dibutyryl cyclic AMP or cholera toxin also resulted in the stimulation of synthesis of the protein. Synthesis of lutropin-induced protein, when maximally stimulated with 100ng of lutropin/m!, could not be stimulated further by addition of dibutyryl cyclic AMP. Addition of 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, further increased synthesis ofthe protein in the presence ofa submaximal dose of lutropin (lOng/ml) but not in the absence of lutropin or with maximal amounts oflutropin (100 and 1000 ng/ ml). Actinomycin D prevented the effect oflutropin on the stimulation oflutropin-induced protein synthesis when added immediately or 1 h after the start of the incubation, but not when added after 5-6h. This is interpreted as reflecting that, after induction of mRNA coding for lutropin-induced protein, lutropin had no influence on the synthesis of the protein in the presence of actinomycin D. Synthesis of the protein was also stimulated in vivo by injection of choriogonadotropin into rats 1 day after hypophysectomy, and the time course of this stimulation of lutropin-induced protein synthesis in vivo was similar to that obtained by incubating Leydig cells in vitro with lutropin. From these results it is concluded that stimulation of lutropin-induced protein synthesis by lutropin is most probably mediated by cyclic AMP and involves synthesis of mRNA.

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“…Studies of Halkerston et al [4] and Constantopoulus et al [5] dealt with the localisation and purification of the adrenal side chain cleavage enzyme, while Hall et al [6] and Toren and collaborators [7] investigated a similar reaction in testicular tissue. Tamoki et al [S] studied the cholesterol side chain cleavage reaction in ovarian tissue, while Ichii et al [9] and Hall et al [lo] presented detailed information about these enzymes using bovine corpora lutea.…”

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The Cholesterol Side Chain Cleavage Enzymes in Immature Rat Ovary

Sulimovici

Boyd

1968

European Journal of Biochemistry

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Cholesterol side chain cleavage reaction has been studied in ovaries of immature female rats pretreated with pregnant mare serum gonadotrophin and human chorionic gonadotrophin. The cleavage enzymes were found to be in the mitochondria and to have the characteristics of a mixed function oxidase requiring NADPH and oxygen. Using [4-14C]cholesterol as substrate the main product obtained was progesterone while pregnenolone and 2Qa-hydroxypregn-4-en-3-one, were formed in smaller amounts. This shows that ovarian mitochondria contains a d5-3P-hydroxysteroid-dehydrogenase, a A 5-614-5 isomerase and a 2 0~h y d r o x y steroid dehydrogenase. The proposed intermediates in cholesterol side chain cleavage (20a-hydroxy cholesterol and 20a, 22~-clihyciroxy cholesterol) were not detected.Mitochondria1 production of progesterone in the presence of NADPH was further stimulated by succinate while fumarate was without effect. I n the presence of NADPH, NADH was found to be inhibitory while NAD' gave rise to an increase in pregnenolone, the overall reaction being unaffected. Excess of NADPH causes an accumulation of pregnenolone and slightly decreases the overall reaction. The action of reduced glutathione (GSH) and ascorbic acid-like reducing agents of physiological occurrence has been studied. It was found that GSH in small amounts stimulates and in larger amounts inhibits the side chain cleavage reaction. Ascorbic acid in physiological amounts produced an inhibitory effect.The action of adenosine 3',5'-cyclic-monophosphoric acid (3'5'AMP) and other nucleotides (AMP, ADP, ATP) was tested. 3'5'AMP markedly stimulates the conversion of cholesterol to pregnenolone and decreases the synthesis of progesterone. The action of AMP shows some similarities with that of 3'5'AMP but the action of ADP and ATP was found to be different.There is a considerable amount of experimental evidence to support the contention that most of the steroid hormones are formed in steroidogenic tissue from cholesterol, and that pregnenolone occupies a central place in the formation of

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The action of gonadotropic hormones upon rabbit testis in vitro

Cited by 125 publications

References 19 publications

Factors Influencing the Secretion of Testosterone in the Anesthetized Dog

Factors Influencing the Secretion of Testosterone in the Anesthetized Dog

Regulation of the synthesis of lutropin-induced protein in rat testis Leydig cells

The Cholesterol Side Chain Cleavage Enzymes in Immature Rat Ovary

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