Inhibition of progesterone synthesis in placenta by administration of dexamethasone to pregnant rats

Heller, Claudia L.; Nicola, Alejandro F. De

doi:10.1016/0022-4731(83)90160-7

Cited by 9 publications

(5 citation statements)

References 23 publications

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“…However, the detailed mechanism through which the pituitary can inhibit luteal function has not been clearly demonstrated. ACTH has been reported to interrupt pregnancy in rats (Yang et al, 1969) and Hellar & de Nicola (1983) (Kato et al, 1982). The progesterone antiserum was raised against lla-hydroxyprogesterone conjugated to BSA, and cross-reacted 58% with 1 la-hydroxyprogesterone, 12% with 11 ß-hydroxyprogesterone, 11% with 5a-3,20-pregnanedione, 3% with deoxycorticosterone, 2-5% with 20a-dihydroprogesterone, 1-7% with 17a-hydroxyprogesterone, and <1% with other progestagens, oestrogens, andro¬ gens and corticoids.…”

Section: Introductionmentioning

confidence: 99%

“…(Châtelain et al, 1980), pro¬ gesterone secretion was increased after adrenalectomy. Since ACTH stimulates the production of adrenocorticosteroids, and since corticosteroids inhibit progesterone production in the rat placenta (Hellar & de Nicola, 1983), it is likely that ACTH exerts its inhibitory effects through the produc¬ tion of corticosteroids. This concept would fit with the present results that corticosterone treat¬ ments inhibited the adrenalectomy-induced rises in progesterone secretion in rats with 1 conceptus (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Inhibitory effects of adrenocorticotrophin or corticosterone on progesterone secretion during mid-pregnancy in rats

Katô

Nanjo²,

Numa³

et al. 1988

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Inhibitory effects of adrenocorticotrophin or corticosterone on progesterone secretion during mid-pregnancy in rats

Katô

Nanjo²,

Numa³

et al. 1988

Reproduction

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“…Serum P4 was determined by RIA [44] after extraction o f the samples with n-hexane. as already published [45]. Results were expressed in ng/ml serum.…”

Section: Determination O F Serum Hormonesmentioning

confidence: 99%

Antagonism by Progesterone of Diethylstilbestrol-lnduced Pituitary Tumorigenesis in Fischer 344 Rats: Effects on Sex Steroid Receptors and Tyrosine Hydroxylase mRNA

Piroli

Grillo²,

Ferrini³

et al. 1996

Neuroendocrinology

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It is known that chronic exposure of F₃₄₄ rats to diethylstilbestrol (DES) induces prolactin (PRL)-secreting pituitary tumors composed of proliferating mammotropic cells. In the present work, we studied the effects of progesterone (P4) on several parameters stimulated in the pituitary tumors (DES-T), such as nuclear estrogen receptors (NE₂R), cytosolic progestin receptors (CP4R) and serum PRL. Additionally, we have measured in hypothalamus the mRNA levels for tyrosine hydroxylase (TH), the rate-limiting enzyme for synthesis of dopamine, the main PRL-inhibitory factor. We found that pellet implantation of P₄ during 1 month significantly reduced weight, ligand binding to NE₂R and CP4R and serum PRL in the tumorous glands. Reductions in sex steroid receptor binding were due to changes in Bmax without changes in K_d, as observed after Scatchard plot analysis. Receptor binding data, therefore, suggests a pituitary site of action of P₄. TH mRNA expression was studied in tuberoinfundibular dopaminergic (TIDA) neurons by in situ hybridization techniques employing a ³⁵S-labeled oligonucleotide probe. Mean number of grains/cell decreased significantly in DES-T, an effect partly reversed by P4 treatment. Frequency histograms were constructed by plotting the number of cells versus the number of grains/cell and examined by χ² test and analysis of residuals. We found that DES-T presented significantly more cells with less grains whereas in control glands, P4-treated rats and DES-T receiving P4, cells with a higher grain number prevailed. These results suggest that in addition to a direct pituitary effect, P4 may also antagonize DES-induced tumorigenesis acting on mRNA for TH and presumably on the activity of TIDA neurons of the hypothalamus. The use of DES-T as a model for hyperprolactinemia may allow further assessment of P4 effects in pituitary adenomas in humans.

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“…The stress of restraint during early pregnancy decreases the average size of litters in rats (Euker & Riegle, 1973;Herrenkohl, 1979;Wiebold, Stanfield, Becker & Hillers, 1986) and serum progesterone concentrations in mice (Wiebold et al 1986). Involvement of the pituitary-adrenal axis in the maintenance of preg¬ nancy has also been demonstrated in several species (Velardo, 1957;Yang, Yang & Lin, 1969;Christian, 1971;Kittinger, Gutierrez-Cernosek, Cernosek & Pasley, 1980;Rosa & Wagner, 1981;Hellar & de Nicola, 1983). Recently, Kato, Nanjo, Numa et al (1988) demonstrated that adrenocorticotrophin (ACTH) and corticosterone inhibit progesterone secretion during mid-pregnancy in rats.…”

Section: Introductionmentioning

confidence: 93%

Different mechanisms for the inhibition of progesterone secretion by ACTH and corticosterone in pregnant rats

Sugino

Tamura²,

Nakamura³

et al. 1991

Journal of Endocrinology

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The present study investigated possible sites through which ACTH or corticosterone inhibit progesterone secretion in pregnant rats, and the role of placental factors in blocking the inhibitory effect. The number of conceptuses was adjusted to one (IC group) or more than ten (FC group) on day 7 of pregnancy by aspirating the desired number. Serum concentrations of progesterone, testosterone and oestradiol were significantly (P less than 0.01) lower on day 15 in the 1C group than in the FC group. Corpora lutea (CL) obtained on day 15 were incubated for 6 h with corticosterone or ACTH. Corticosterone (1 mumol/l) significantly (P less than 0.05) inhibited progesterone secretion in the 1C group but not in the FC group. The inhibitory effect of corticosterone in the 1C group was completely blocked by co-addition of 1 mumol testosterone/l or 1 mumol oestradiol/l but not by 1 mumol dihydrotestosterone/l. ACTH (1 microgram/l-1 mg/l) had no direct effect on progesterone secretion in either the 1C or the FC groups, although ACTH apparently decreases progesterone secretion in vivo. Placentae obtained from rats of the FC group on day 15 were incubated for 24 h with or without ACTH (1 mg/l). The supernatant after placental incubation without ACTH significantly (P less than 0.01) increased progesterone secretion by the CL in both the 1C and FC groups, and also eliminated the inhibitory effect of corticosterone in the 1C group. The supernatant after placental incubation with ACTH also increased progesterone secretion in the FC group as effectively as the supernatant from the control incubation, but it had no effect in the 1C group.(ABSTRACT TRUNCATED AT 250 WORDS)

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Inhibition of progesterone synthesis in placenta by administration of dexamethasone to pregnant rats

Cited by 9 publications

References 23 publications

Inhibitory effects of adrenocorticotrophin or corticosterone on progesterone secretion during mid-pregnancy in rats

Inhibitory effects of adrenocorticotrophin or corticosterone on progesterone secretion during mid-pregnancy in rats

Antagonism by Progesterone of Diethylstilbestrol-lnduced Pituitary Tumorigenesis in Fischer 344 Rats: Effects on Sex Steroid Receptors and Tyrosine Hydroxylase mRNA

Different mechanisms for the inhibition of progesterone secretion by ACTH and corticosterone in pregnant rats

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