Thymulin (Serum Thymic Factor) Modulation of Porcine Granulosa Cell Responsiveness to Gonadotropins In Vitro

Ledwitz-Rigby, Florence; Scheid, P.

doi:10.1007/978-1-4612-3200-1_61

Cited by 7 publications

(7 citation statements)

References 15 publications

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“…Although Meishan boar testis responded to hCG with increases of testosterone concentrations, thymulin treatment had no effect in augmenting the hCG stimulation of testosterone increases in vitro. There was an increase in testosterone, but not DHEA+DHEASO 4 , concentrations from testis treated with hCG plus thymulin from White composite boars, which is similar to the report of thymulin synergizing with hCG in stimulating granulosa increases of progesterone concentrations in vitro (Ledwitz-Rigby and Scheid, 1991).…”

Section: Discussionsupporting

confidence: 86%

“…rodents (Ledwitz-Rigby and Scheid, 1991;Wise, 1998), but no information is available on effects of thymic peptides in vitro or in vivo using farm animals.…”

Section: Discussionmentioning

confidence: 99%

“…Thymulin, a peptide produced by thymic epithelial cells, can affect many endocrine systems (Bach and Dardenne, 1989;Dardenne and Savino, 1994). Ovarian responses to thymulin include a thymulin-augmented gonadotropic increase in granulosa maturation and progesterone secretion (Ledwitz-Rigby and Scheid, 1991) and an increase in ovarian weights and ovulation rates (Hinojosa and Rosas, 1996), but little is known about the effects of thymulin on testicular function. In vitro testicular steroidogenic activity from Meishan boars that have increased gonadotropins compared to boars of European origin may be a more sensitive model for thymulin augmentation of LH stimulation of testicular steroidogenesis.…”

Section: Introductionmentioning

confidence: 99%

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Effects of the thymic peptide thymulin on in vitro and in vivo testicular steroid concentrations in white composite and Meishan boars.

Wise

Ford²

1999

Journal of Animal Science

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Immuno-peptides may have positive or negative effects on gonadal steroidogenesis, but few have been tested outside of rodent species or in vivo. In Exp. 1, thymulin, a secreted nonapeptide of the thymus, was incubated (1, 10, 100, or 1,000 ng/mL) with testicular minces (sampled at 3, 6, or 12 h) from Chinese Meishan boars of high gonadotropin/testicular steroidogenic function (n = 8) and White composite boars of European origin (n = 8 ) to test the hypothesis that thymulin could augment hCG stimulation of testicular androgen concentrations. Thymulin alone had few effects on androgen concentrations (testosterone, dehydroepiandrosterone+dehydroepiandrosterone sulfate [DHEA+DHEASO4]) in Meishan boar testicular incubates. In minces from White composites incubated with thymulin, testosterone concentrations were generally below control values (P<.05), but DHEA+DHEASO4 concentrations were unaffected. Thymulin had no effect on estrone concentrations in testicular incubates of White composite boars but stimulated estrone concentrations in Meishan testicular incubates. Thymulin plus hCG increased testosterone (3 and 6 h of incubation; P<.05) but not DHEA+DHEASO4 concentrations in White composite testicular incubates. Thymulin plus hCG did not alter androgen or estrogen concentrations from control values in Meishan testicular incubates. In Exp.2 with a protocol similar to that of Exp. 1 for testicular minces from White composite boars (n = 30), thymulin increased testosterone concentrations during the early incubation period (1 to 3 h; P<.05) and depressed testosterone concentrations at later times (6 h; P<.05). Thymulin synergized with hCG in stimulating increases in testosterone and DHEA+DHEASO4 concentrations (P<.05) but had no effect on estrone concentrations in vitro. Thymulin was tested in vivo in boars from three genetic lines selected for high, medium, or normal circulating LH concentrations (Meishan, select White composites, and control White composites, respectively). Injection of thymulin i.v. (4.4, 44.4, or 444.4 ng/kg BW) generally increased circulating testosterone concentrations (2 to 3 h later; P<.01), but the response was dependent on the boar's general circulating LH concentrations and dose of thymulin. Overall results from these studies support the hypothesis of a thymulin augmentation of LH stimulation of androgen increases in vitro and in vivo in the testis of boars.

show abstract

Section: Discussionsupporting

confidence: 86%

“…rodents (Ledwitz-Rigby and Scheid, 1991;Wise, 1998), but no information is available on effects of thymic peptides in vitro or in vivo using farm animals.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of the thymic peptide thymulin on in vitro and in vivo testicular steroid concentrations in white composite and Meishan boars.

Wise

Ford²

1999

Journal of Animal Science

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“…In turn, as the injection of thymulin to Tx-10 animals resulted in normal onset of puberty and serum oestradiol concentrations, we suggest that thymulin is one of the peptides used by the thymus in its participation in the regulation of ovarian function. In this regard, there is evidence that thymulin increases ovarian aromatase activity (Ledwitz-Rigby & Scheid 1990), in addition to secretion of LH by the pituitary (Zaidi et al 1988).…”

Section: Discussionmentioning

confidence: 99%

Effects of infantile thymectomy on ovarian functions and gonadotrophin-induced ovulation in prepubertal mice: role of thymulin

García¹,

Hinojosa²,

Domı́nguez³

et al. 2000

Journal of Endocrinology

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The effects of thymectomy performed on 10-day-old (Tx-10) mice on spontaneous puberty and the ovulatory response induced by gonadotrophin treatment were analysed, together with the effects of thymulin replacement from 10 days of age. Infantile thymectomy induced a delay of puberty, a decrease in serum 17 -oestradiol concentration and a reduced total number of follicles. Injection of thymulin (12 ng/g body weight) to Tx-10 mice resulted in an earlier onset of puberty, a decrease in the weights of ovaries and uterus, and an increase in serum 17 -oestradiol concentrations. In control and Tx-10 mice, treatment with pregnant mare serum gonadotrophin (PMSG) (5 IU) at 25 days of age resulted in ovulation and the numbers of ova shed by ovulating animals were similar. When the animals were injected with 1 IU PMSG ovulation did not occur. In Tx-10 mice, both 1 and 5 IU PMSG increased the number of follicles to values similar to those observed in the controls. In Tx-10 mice the sequential injection of PMSG (1 IU) and human chorionic gonadotrophin (hCG) (3 IU) resulted in ovulation, but the number of ova shed was lower than in controls. When these animals were injected daily with thymulin, an increase in the number of ova shed and serum 17 -oestradiol concentrations was observed. The uterine weight of Tx-10 mice was always significantly reduced in response to gonadotrophin treatment. Thymulin injection in PMSG-hCG-treated Tx-10 mice provoked a significant increase in uterine weight. The results suggest that the presence of the thymus after the neonatal period is necessary to normal ovarian development and function. The increase in gonadotrophin-induced ovarian response produced by thymulin replacement indicates that this peptide has a role in this process as one of the connecting signals between thymus and ovaries.

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“…In vitro studies show that in both, male and female gonads, thymulin modulates steroidogenesis (Ledwitz-Rigby and Scheid, 1990;Wise, 1998). In in vitro conditions, the addition of thymulin to pituitary tissue obtained from adult male rats stimulates the release of luteinizing hormone (LH) in a dose-related way; similar to the responses obtained by adding gonadotropin-releasing hormone (GnRH) (Zaidi et al, 1988;Hadley et al, 1997).…”

Section: Introductionmentioning

confidence: 89%

Effects of thymulin and GnRH on the release of gonadotropins by in vitro pituitary cells obtained from rats in each day of estrous cycle

Hinojosa¹,

García²,

Domı́nguez³

et al. 2004

Life Sciences

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Thymulin (Serum Thymic Factor) Modulation of Porcine Granulosa Cell Responsiveness to Gonadotropins In Vitro

Cited by 7 publications

References 15 publications

Effects of the thymic peptide thymulin on in vitro and in vivo testicular steroid concentrations in white composite and Meishan boars.

Effects of the thymic peptide thymulin on in vitro and in vivo testicular steroid concentrations in white composite and Meishan boars.

Effects of infantile thymectomy on ovarian functions and gonadotrophin-induced ovulation in prepubertal mice: role of thymulin

Effects of thymulin and GnRH on the release of gonadotropins by in vitro pituitary cells obtained from rats in each day of estrous cycle

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