Search results

Sort By:

Limit search:

Simultaneous determination of plasma ovarian and thyroid hormones during sexual maturation of the hen (Gallus domesticus)

100%

Sechman A., Rzasa J., Paczoska-Eliasiewicz H., Hrabia A.

Folia Biologica

2000

vol. 48

issue 1-2

7-12

The concentrations of ovarian steroids (estradiol ? E2, progesterone ? P4 and testosterone ? T) and thyroid hormones (thyroxine ? T4 and triiodothyronine ? T3) were determined in blood plasma of the domestic hen during sexual maturation and the initial period of egg lay. Blood samples were collected from Hy-Line pullets at 3 day intervals from days 87 to 144 day of life, i.e. 42 days before and 14 days after the onset of egg lay (OEL). Ovarian and thyroid hormones were measured by RIA methods. During sexual maturation an increase in ovarian steroids in the blood plasma was observed. The maximum E2 and P4 levels were recorded on day 6 and day 3 prior to OEL, respectively. In the case of plasma T level, an increase from 42 to 18 days before OEL followed by a decrease and a renewed increase from day 9 till OEL was observed. The relatively unchanged plasma level of T4 until day 9 before OEL decreased significantly just before the first oviposition while the T3 level gradually decreased between day 42 and day 9 before OEL, and then increased and again decreased from day 3 before till day 3 after OEL. During sexual maturation the following statistically significant coefficients of correlation between ovarian steroids and T3 were found: E2 vs. T3 ? r = -0.551 and P4 vs. T3 ? r = -0.373. There was no significant correlation between T and T3 or between the examined steroids and T4. The data obtained indicate that during sexual maturation of the domestic hen there is a negative relationship between the ovary and the thyroid gland.

Effect of 9-cis retinoic acid (RA) on sex hormone secretion and RA receptor expression in chicken ovarian follicles

88%

Pawlowska K., Sechman A., Suchanek I., Grzegorzewska A., Rzasa J.

Folia Biologica

2008

vol. 56

issue 1-2

65-72

Several lines of evidence indicate that retinoids, derivates of vitamin A, affect reproductive function in birds, however, the mechanism of their action in the ovary is still unknown. Therefore, the present study was designed (i) to show whether in the domestic hen 9-cis retinoic acid (9-cis RA), one of the retinoids, influences steroid secretion in vitro by white and yellow chicken ovarian follicles, and (ii) to detect expression of retinoic acid RXR receptor mRNA in these follicles. The white follicles (small: 1-4 mm, medium: 4-6 mm and large 6-8 mm in diameter) and the three largest yellow preovulatory follicles (F3-F1; 25-37 mm) were isolated from the ovary 3 h before ovulation. The granulosa layer was separated from the theca layer in the preovulatory follicles, which were subsequently divided into 4 equal pieces. The isolated whole white follicles or parts of the granulosa or theca layers were incubated for 24 h at 38oC in Eagle's medium in the following 4 groups: control, ovine LH (oLH; 10 ng/ml), 9-cis RA (100 ng/ml) and 9-cis RA + oLH. After incubation, the medium was collected for estradiol (E2) and progesterone (P4) determination while tissues were saved for protein assay. It was found that 9-cis RA affects steroid secretion from chicken ovarian follicles. It decreased E2 secretion from white follicles and from the theca layer of the two largest (F2 and F1) preovulatory follicles. 9-cis RA had no effect on oLH-stimulated E2 secretion by the white follicles and yellow F2 and F1 follicles, but it diminished E2 secretion by F3 follicles. As regards P4, the effect of 9-cis RA was opposite; it increased P4 secretion from the granulosa layer of all preovulatory follicles. 9-cis RA did not change oLH-stimulated P4 secretion by granulosa layers of F3 and F2 follicles, however, it inhibited oLH-enhanced P4 secretion from the F1 granulosa layer. In a separate experiment, the presence of mRNA encoding RXR was found in the stroma and all follicles of the chicken ovary by means of the RT-PCR technique. The results indicate that retinoids, acting by specific nuclear receptors, are modulators of follicular steroidogenesis in the chicken ovary.

Refine search results

2 Folia Biologica

1 2008

1 2000

2 Rzasa J.

2 Sechman A.

1 Grzegorzewska A.

1 Hrabia A.

1 Paczoska-Eliasiewicz H.

1 Pawlowska K.

1 Suchanek I.

Search results

Simultaneous determination of plasma ovarian and thyroid hormones during sexual maturation of the hen (Gallus domesticus)

Effect of 9-cis retinoic acid (RA) on sex hormone secretion and RA receptor expression in chicken ovarian follicles