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Biomedical subjects

B Robinzon

Publications and source records attributed to B Robinzon.

At least 73 records · Page 4Linked to original sources
PubMed1986

The gonadotropic-axis involvement in the course of the filial following response in the domestic fowl chick.

The detachment process of the domestic chick from its mother, or any other imprinting object occurs between the sixth and tenth week after hatching. The present study (Experiment I), examines whether the detachment process parallels endocrine events that precede prepuberty. Immediately upon hatching, groups of heavy strain chicks were imprinted to a colored foam rubber ball for 72 hours. The bond between these chicks and the imprinting object was then tested, and plasma LH and testosterone were assayed once a week until the chicks were 10 weeks of age; the sexual development of chicks of the same strain was studied at the same time. At the outset of the detachment period (5-7 weeks) an increase in plasma testosterone and a decrease in plasma LH was found. In addition, the comb and testes showed a definite weight increase while the bursa of Fabricius showed a significant decline in weight. In Experiment II, the beginning of the detachment process was induced by injecting 3 to 4 week old chicks with testosterone-propionate, estradiol-benzoate and 5 alpha-dihydrotestosterone. Our evidence therefore appears to demonstrate that testosterone and its metabolites induce the detachment process by the same mechanism used to stimulate sexual behavior in juvenile chicks.

Animals↗
PubMed1986

Induction of precocious development of reproductive function in cockerels by tamoxifen administration.

To examine the effects of tamoxifen, a known estrogen antagonist in the chicken, two groups of cockerels were injected every other day from hatching until 7 weeks of age with 1 and 10 mg tamoxifen/kg body weight (BW), respectively. A third group was injected with 1 mg tamoxifen/kg BW every 3 days from 5 to 10 weeks of age. All groups treated with tamoxifen had increased testes weight, but BW and pituitary weights did not differ from controls. In contrast to controls, seminiferous epithelium of testes from treated cockerels showed spermatogenesis up to the spermatid elongation stage. We suggest that the antiestrogen effect of tamoxifen increased circulating LH, which stimulated testes growth and precocious spermatogenesis.

Animals↗
PubMed1984

An improved method for obtaining semen from Muscovy drakes and some of its quantitative and qualitative characteristics.

An improved method for obtaining semen from the Muscovy drake using an "artificial vagina" was developed and employed on a commercial scale. With such a procedure, the ejaculate volume was 1.12 +/- .85 ml, semen concentration was 1.35 +/- .43 X 10(9) cells/ml with 8.6 +/- 6.3% abnormal sperm cells. Average spermatozoal motility was graded as 3.59 +/- .93 on a scale of 0 to 5 and the initial pH was found to be 7.30 +/- .23 within 5 min of ejaculation.

Animals↗
PubMed1984

The effect of supplementation of daylight with artificial light from various sources and at two intensities on the egg production of two lines of geese.

Three light sources: Cool-White (C), Vita-Lite (V), and tungsten (T), each at two intensities (20 or 50 lx), were used to supplement light to 16 hr in a 24-hr cycle for geese maintained in open-shed pens. Two lines of mixed breeds of geese, white and grey, were used and egg production was followed from the 27th week of age through 6 months of the laying period. A significant increase in egg production was found under the C light illumination. At 20 lx, egg production was significantly higher than at 50 lx. No difference in egg production was found between the two lines of geese; however, significant interactions were found between light sources, intensities, and geese lines, as exhibited by different patterns of egg production. Light intensity had the greatest effect until peak egg production had been reached; thereafter, egg production was influenced mainly by the light source.

Animals↗
PubMed1984

The effect of clomiphene-citrate on broody turkey hens.

The effect of clomiphene-citrate (CC) on broody turkey hens was examined in three experiments. Turkey hens were categorized as broody if found in the laying nest during 6 successive checks per day, if they were reluctant to leave the nest for a period of 24 hr or more, if they had ruffled feathers, and if their cloacal orifices were contracted so as to prevent vaginal exposure by abdominal massage during artificial insemination. In each experiment, 20 hens, selected as broody from commercial breeding flocks, were treated; half were treated with CC at a dosage of 6 mg/kg body weight/day (per os) for 5 consecutive days, and the rest (control) received parallel treatment with a placebo (CaCO3). In all experiments, the CC administration alleviated brooding behavior and increased egg production.

Animals↗
PubMed1983

The involvement of gonads and gonadal steroids in the regulation of food intake, body weight and adiposity in the white Leghorn cock.

The effects of long-term injections of testosterone propionate (TP), diethylstilbestrol (DES) and TP+DES simultaneously to castrated and sham-operated White Leghorn cocks on feeding, weight gain, obesity, blood lipids and weight of various glands were studied. DES induced marked adiposity while TP reduced carcass fat content. Injections of TP+DES induced only moderate obesity. The responses of the castrated cocks to TP or DES were not always parallel to those of the sham-operated ones. In sham-operated cocks, TP induced permanent hypophagia and emaciation while in castrated cocks, although alleviating adiposity, it did not reduce the rate of weight gain and induced only a transient hypophagia. DES induced permanent hyperphagia and accelerated weight gain in sham-operated cocks while in those castrated, it induced only transient hyperphagia which later on changed into hypophagia. Although the latter cocks did not gain more weight than those castrated with no steroids supplementation, they were much more obese and had a fat content similar to that of the sham-operated ones treated with DES. The castration was found to alleviate the depressing effect of TP on adenohypophyseal and thyroidal weights. The results may suggest: (1) In the White Leghorn cocks, DES increases lipogenesis and food intake while TP results in the contrary. (2) Castration should not be considered as a lack of gonadal steroids only.

Adipose Tissue↗
PubMed1983

Intraventricular glucose administration inhibits feeding in satiated but not in 24 hours food deprived cocks.

Injection of 5 microliter isotonic glucose into the third ventricle above the basal hypothalamus but not in the posterior hypothalamus-anterior midbrain, suppressed feeding in satiated cocks. This suppression of food intake was less dramatic when glucose was injected after 5 hr of food deprivation and was eliminated if 24 hr of food deprivation preceded the glucose administration. An involvement of a glucostatic mechanism in the regulation of feeding in the chicken is suggested.

Animals↗
PubMed1983

Pharmacological disruption of broodiness in White Rock domestic fowls.

The administration of bromocriptine (CB154) to broody hens (Gallus domesticus) impaired resumption of lay. Resumption of lay was stimulated in broody birds treated with clomiphene citrate (an anti-oestrogen) alone or following CB154 administration. The increased oviposition rate following a single intramuscular injection (21 mg) of clomiphene was long lasting, persisting for at least 16 weeks after treatment. Treatment of broody hens with clomiphene consistently improved (by 4%) the hatchability of the fertile eggs subsequently laid.

Animals↗
PubMed1982

Adenohypophyseal cytology of chemically and surgically thyroidectomized cockerels.

Reproductive traits and histology of the adenohypophysis were studied in adult White Leghorn cockerels after surgical thyroidectomy or .1% propylthiouracil (PTU) food supplementation. Both treatments caused hypothyroidism as judged by a marked reduction in plasma thyroxine levels, a decrease in resting metabolic rate values, an increase in liver and adipose tissue weights, and a marked elevation in the alcianophilic cell population in the adenohypophysis. Both the PTU-treated and thyroidectomized birds demonstrated reduced testes and comb weights. However, although thyroidectomy was found to increase the number of PAS-positive cells in the adenohypophysis, the PTU treatment reduced them. This phenomena is discussed.

Animals↗
PubMed1976

The drinking response of the chicken to peripheral and central administration of angiotensin II.

Intravenous injection of Ang II (val5 angiotensin II amide) elicited an immediate drinking response in the domestic fowl which lasted at least 20 minutes. The minimal dosage needed was 300 mug. Intracranial injection of 10 mug Ang II through cannulas implanted in the anterior diencephalon caused a significant increase in water intake. The minimal intracranial dosage of Ang II which evoked drinking was 2.5 mug. Intracranial injection of isotonic KCl inhibited the drinking response induced by intravenously injected Ang II when administered simultaneously. This suggests that drinking caused by both intravenous or intracranial injection of Ang II is activated through identical brain regions. The positive drinking response of the chicken is repeated concecutive intracranial injections of Ang II declined from the first injection through the following ones.

Angiotensin II↗
PubMed1976

Involvement of the medial hypothalamus and the septal area in the control of food intake and body weight in geese.

Intracranial injections of 6-OHDA were used to destroy the following brain areas of male geese: bilateral VMH-mamillary (BL-VMH), unilateral VMH (UL-VMH), septal area, and bilateral hypothalamic areas located dorsal, lateral, caudal and rostral to the VMH. The brain damage was nonspecific, destroying cell bodies as well as axons. The effects of these lesions were determined on food intake, body weight, abdominal adipose tissue, liver weight and fat content, and on selected endocrine gland weights. The highest food intake, obesity and liver weight and its fat content were exhibited by the BL-VMH lesioned geese. The UL-VMH and the septal lesioned geese showed moderate increase in food intake, which eventually decreased in the UL-VMH but remained constant in the septal lesioned ones. The liver fat content of the latter groups of geese was higher than the controls. No differences were found between the controls and the group of geese lesioned in the various hypothalamic areas - excluding the VMH - in all parameters measured. While no significant differences were found in pituitary, thyroid and adrenal weights among all groups of geese, a decrease in testes weight was noted in the lesioned groups of geese as compared to the controls. The interrelationships between body weight, food intake, adiposity and liver weight are discussed.

Adipose Tissue↗
PubMed1975

The relation between monosodium glutamate inducing brain damage, and body weight, food intake, semen production and endocrine criteria in the fowl.

Various dosages of monosodium glutamate (M.S.G.) were injected to 5 day old male chicks. Body weights, food intake, rate of obesity, semen production, some endocrine criteria and brain pathology were studied til 235 days post injection. All M.S.G. treated birds showed brain damage in the rotundus nuclei, and in the area located dorsolaterally to the ventromedial hypothalamic nuclei (V.M.H.). In some of the M.S.G. treated birds, additional brain regions were damaged, i.e. V.M.H., mammillary nuclei, dorsomedial anterior nuclei, ovoid nuclei, subrotundus nuclei, archistriatum and lateral forebrain bundles. Some of the M.S.G. treated birds showed marked abdominal fat deposition or low spermatozoan motility. It was impossible to attribute these changes to the dosage of M.S.G. injected. No significant differences were found in these parameters between the treated birds and the saline injected ones. When the M.S.G. treated birds were categorized on the basis of brain damage in specific sites, the following was observed: 1) Birds with V.M.H. damage accumulated significant larger amounts of fat in the abdominal adipose tissue than the rest of the M.S.G. treated birds. 2) Those M.S.G. treated birds, showing brain damage in their mammillary nuclei, produced semen of a very low spermatozoan motility rate as compared to the rest of the M.S.G. treated birds and the controls.

Adipose Tissue↗