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At least 1,081 records · Page 60Linked to original sources

PubMed1981

Effects of steroid blockers on LH-induced ovulation in the domestic fowl, Gallus domesticus.

The spontaneous ovulation of hens was suppressed by daily injection of PMSG. The LH injected to overcome the block was accompanied by one of 4 compounds known to inhibit steroidogenesis at different sites in the biosynthetic pathway. A dose of 300 mg aminoglutethimide phosphate, which inhibits the conversion of cholesterol to 20 alpha-hydroxycholesterol, blocked the LH-induced ovulation and prevented the normal rise in plasma progesterone. Metyrapone, an inhibitor of 11 beta-hydroxylase, and SC 12937 and AY 9944, inhibitors of cholesterol synthesis, did not prevent ovulation or the progesterone rise induced by exogenous LH. Administration of progesterone overcame the inhibitory effect of aminoglutethimide, and it is suggested that progesterone is involved in the ovulatory process of the fowl.

Aminoglutethimide↗

PubMed1982

Proteolytic enzymes and gonadal hormones of the ovarian follicle wall during ovulation in the domestic fowl (Gallus domesticus).

There were no significant changes in the activities of collagenase, acid and neutral protease up to ovulation. Neutral protease activity increased significantly in the post-ovulatory follicle obtained immediately after ovulation. Acid protease and collagenase showed an increasing activity with time after ovulation. The progesterone concentration of the follicle wall rose 3 h before ovulation, peaked 1 h before ovulation and remained high until ovulation. Plasma progesterone values were high but decreased before those in the follicle. Follicular progesterone concentrations decreased markedly soon after rupture, but oestradiol values then increased.

Animals↗

PubMed1982

Distribution of blood flow in the ovary of domestic fowl (Gallus domesticus) and changes after prostaglandin F-2 alpha treatment.

Radioactive microspheres (14Ce- and 46Sc-labelled) were used to show that the 5 major pre-ovulatory follicles receive about half of the ovarian blood flow. A progressive increase in the blood flow to these pre-ovulatory follicles during their maturation was observed. Blood flow to the post-ovulatory follicles was low. The administration of PGF-2 alpha was followed by a consistent decrease in blood flow to the major pre-ovulatory follicles.

Animals↗

PubMed1984

Effects of gonadotrophins, sex steroids and adenohypophysectomy on the activities of proteolytic enzymes in the ovarian follicle wall of the domestic fowl (Gallus domesticus).

LH and progesterone added to cultures of the follicle wall of hens increased the total activity of neutral and acid proteases and collagenase and the increase was greater for follicle tissues from the stigma region. Adenohypohysectomy of hens resulted in the decreased activities of neutral and acid proteases and collagenase in the first and second largest follicles.

Animals↗

PubMed1985

Effects of gonadotrophins on progesterone production by isolated granulosa cells of the adenohypophysectomized domestic fowl (Gallus domesticus).

Ovine LH and ovine FSH stimulated progesterone production in granulosa cells isolated from the F1, F2 and F3 follicles of hypophysectomized and control (sham-operation) hens when they were collected 6 h after operation, but the steroidogenic response to LH was greater for granulosa cells from hypophysectomized hens. At 15 h after operation progesterone production by granulosa cells was stimulated by LH in all 3 follicle types of control hens, but only in the F1 follicles of hypophysectomized hens. The response to FSH at 15 h was similar for control and hypophysectomized hens. The time after hypophysectomy therefore appears to affect the LH-stimulated progesterone production by granulosa cells of the F2 and F3 follicles.

Animals↗

PubMed1987

Regulation of the length of the fertile period in the domestic fowl by numbers of oviducal spermatozoa, as reflected by those trapped in laid eggs.

The numbers of spermatozoa trapped in the vitelline membrane of laid eggs were counted after staining with the fluorochrome 2,4-diamidino-2-phenylindole. In a group of 24 hens inseminated with different numbers of spermatozoa to produce different lengths of fertile periods, the numbers of spermatozoa in successive eggs from each hen decreased logarithmically with respect to days following insemination. A relationship could be described between the numbers of spermatozoa per unit area of membrane of an egg and the probability of that egg being fertile. After insemination the number of spermatozoa on successively-laid eggs appears to become reduced until a critical value is reached, after which the hen will lay infertile eggs. By estimating the day on which the critical value was achieved, the actual length of the fertile period could be predicted. It is suggested that the numbers of spermatozoa trapped in the vitelline membrane of laid eggs represent those which surround the ovum at the time of fertilization.

Animals↗

PubMed1992

Induction of immunity to spermatozoa in male domestic fowl and effects on fertility.

Male fowl were immunized intravenously (i.v.) or intramuscularly (i.m.) with spermatozoa to assess the effects of immunity to spermatozoa on fertility. Histological and immunofluorescence evaluations of testis and ductus deferens tissues after 24 weeks of immunizations revealed immune cell infiltration and immunoglobulin associated with spermatozoa. The long-term immunization regimen resulted in significant antisperm antibody titres in the immunized groups. When semen from i.v.-immunized males was used to inseminate females, fertility over 7 days was reduced (P less than 0.05). A subsequent experiment using a 10-week i.v. immunization scheme also led to high antisperm titres. Spermatozoa from these males were characterized by lower fertility and duration of fertility than those of controls (P less than 0.05). As in mammals, a reduction in fertility may result from exposure of avian males to sperm antigens.

Animals↗

PubMed1995

Differential sensitivity of ovarian follicles to gonadotrophin stimulation in broiler and layer lines of domestic fowl.

Differences in the reproductive potential of female broiler parent and layer fowl are related to differences in the recruitment of follicles to the preovulatory hierarchy. Broiler and laying hens were fed ad libitum or a restricted diet during rearing and ad libitum after sexual maturity. The sensitivity of thecal tissue, from ovarian follicles of different sizes, from layer and broiler fowl to stimulation by pregnant mares' serum gonadotrophin (PMSG) was determined to test the hypothesis that differences in egg production are associated with changes in the sensitivity of ovarian follicles to stimulation by gonadotrophin. The activity of ornithine decarboxylase 0.5-4 h after injection of 200 iu PMSG kg-1 body mass was assessed in thecal tissue from small white follicles 2-3 and 5-6 mm in diameter and in the smallest preovulatory yellow follicle. Basal activity was similar in layers and broiler breeders. PMSG-stimulated ornithine decarboxylase activity in follicles of 5-6 mm diameter was greater in broiler breeders than in layers. There was no difference between the lines in PMSG-stimulated ornithine decarboxylase activity in follicles of 2-3 mm diameter or in small yellow follicles. It was concluded that the low egg production and high prevalence of eggs with defective shells in broiler parents compared with layers may be related to the increased sensitivity of follicles to endogenous gonadotrophins at the critical stage of recruitment to the preovulatory hierarchy.

Animal Nutritional Physiological Phenomena↗

PubMed1990