Change in the relative importance of oestrone and oestradiol synthesis by the rat ovary between fetal and prepubertal stages

Weniger, J.-P.; Zeis, A

doi:10.1530/jrf.0.0810479

Cited by 6 publications

(3 citation statements)

References 12 publications

(19 reference statements)

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“…Production of E 2 by the ovary was low and was not affected by either the gonadotropin treatment in vivo or the subsequent short-time incubation in vitro with gonadotropins. This is consistent with previous studies in which perinatal rat ovaries below the age of 11 days did not respond to gonadotropins with production of E 2 [21,42]. However, aromatase activity has been shown in cultured ovaries in the presence of androgen precursors even at the age of 4-5 days [18,40,43], and the activity increases during the first two postnatal weeks [44].…”

Section: Discussionsupporting

confidence: 92%

Development of Luteinizing Hormone Action in the Perinatal Rat Ovary1

Sokka

Hämäläinen

Kaipia

et al. 1996

Biology of Reproduction

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The expression of LH receptor (LHR) mRNA was studied in fetal rat gonads using polymerase chain reaction multiplication of reverse-transcribed mRNA. A primer pair corresponding to the extracellular domain of the receptor revealed the expression of LHR mRNA in fetal ovaries and testes as early as embryonic Day 13.5, the earliest age studied. The localization of LHR mRNA was examined in the perinatal rat ovary using in situ hybridization with two antisense probes, one encoding the extracellular and the other encoding the transmembrane domains of LHR. At the age of 4 days, only the extracellular LHR probe gave specific signal over ovarian stromal and follicular cells, excluding the ova. Three days later, similar distribution of specific hybridization was observed with both probes. In the 10- and 30-day-old rat ovaries, clear expression of LHR mRNA was found to be with both probes in theca cells. Gonadotropin-stimulated production of cAMP was studied in cultures of dispersed perinatal rat ovarian cells. When 5-day-old ovarian cells were cultured for 3 days in vitro and then stimulated by either hCG (0.1 mg/L) or FSH (1 mg/L) for 6 h, cAMP production was enhanced only in cells stimulated by FSH. In a similar experiment with 7-day-old ovarian cells, cAMP production was stimulated by both FSH and hCG. Stimulation with hCG (0.1 mg/L) during the 3-day culture caused homologous desensitization of cAMP production, but stimulation with FSH (0.1 mg/L) had no such effect. The desensitization of the LHR was also investigated by treating neonatal rats in vivo with a high dose of hCG (600 IU/kg BW s.c. as a single injection on Day 7) or with a dosage of recombinant human (rec) FSH on Days 3-9 (0.3 IU s.c twice daily). Thereafter, at the age of 10 days, the ovaries were incubated either with recFSH (200 IU/L) or hCG (CR-121; 0.1 mg/L) for 1 h. Homologous desensitization of cAMP production by hCG was observed, but the FSH-mediated cAMP production was not affected. The hCG-induced steroidogenesis (progesterone and testosterone production) was not desensitized. In conclusion, these findings indicate that 1) the expression of the mRNA encoding the extracellular domain of LHR, i.e., truncated receptor, occurs in fetal rat gonads as early as embryonic Day 13.5; 2) the expression of the truncated LHR mRNA occurs uniformly in the differentiating ovarian cells before the appearance of the functional theca cell layer; 3) full-length LHR message appears in the developing ovary concomitantly with appearance of differentiated theca cells; 4) homologous desensitization of cAMP output by hCG, without steroidogenic desensitization, is present in perinatal rat ovaries; and 5) no FSH-evoked desensitization of cAMP production occurs in perinatal ovaries.

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Section: Discussionsupporting

confidence: 92%

Development of Luteinizing Hormone Action in the Perinatal Rat Ovary1

Sokka

Hämäläinen

Kaipia

et al. 1996

Biology of Reproduction

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“…In none of 3 successive studies could stimulation of aromatase activity by FSH be demon¬ strated unequivocally (Weniger et al, 1985;Weniger & Zeis, 1987b, 1988b. Nor did George & Ojeda (1987) notice any augmentation of aromatase activity in 19-22-day-old fetal rat ovaries treated with FSH.…”

Section: Action Of Fsh and Campmentioning

confidence: 94%

“…However, this hypothesis loses strength because chick embryo ovaries cultured under the same conditions as used in the fetal rat ovary produced mainly oestradiol (Weniger et al, 1983). It can be dismissed in view of the results obtained when culturing fetal rat ovaries in Medium 199, in which synthesis was almost exclusively of oestrone (Weniger & Zeis, 1987b). This result was confirmed independently by Picon et al (1985), who found that oestrone production was 12-fold that of oestradiol.…”

Section: Introductionmentioning

confidence: 97%