Statistical Studies of the Seasonal Changes in the Pituitary Gland of Rasbora daniconius (Pisces: Cyprinidae)

Bhargava, H. N.; Raizada, Arun

doi:10.2307/1442980

Cited by 5 publications

(4 citation statements)

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“…Gonadotrops increased in number and nuclear diameter during periods of recrudescence. Similar seasonal changes in presumptive gonadotrop activity of cyprinids have been reported previously (Beach, 1959;Bhargava & Raizada, 1973;Nagahama, 1973;Chiba et al, 1978).…”

Section: Discussionsupporting

confidence: 87%

Seasonal changes in the pituitary‐ gonad axis of feral goldfish, Carassius auratus L., from Ontario, Canada

Munkittrick

Leatherland

1984

Journal of Fish Biology

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Apparently healthy, feral goldfish, Carassius auratus L., were collected from a pond in Cambridge, Ontario from March until November 1981, and during April 1982. Based on histological examination, oocyte development was divided into five stages and the reproductive cycle into five periods. The origins of oogonia and the atresia process were examined. The gonadosomatic index (GSI) was found to be an accurate indicator of ovarian activity in the feral population. Based on the GSI, proportion of various oocyte stages and egg size, females older than 2 years appeared to spawn during two periods, May to June and late August; 2-year-old fish spawned in the first period. There was a reduction in the density, abundance and nuclear diameter of presumptive pituitary gonadotrops in early August, after the completion of ovarian development and before the completion of spawning.

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Section: Discussionsupporting

confidence: 87%

Seasonal changes in the pituitary‐ gonad axis of feral goldfish, Carassius auratus L., from Ontario, Canada

Munkittrick

Leatherland

1984

Journal of Fish Biology

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“…Originally, researchers theorized that seasonal variations in GH contributed to the growth cycle observed (Pickford 1957;Gross et al 1965;Gerking 1966;Adelrnan 1977;Kayes 1977;Brett 1979). Due to the lack of radioimmunoassays, several studies utilized indirect assessments of the pituitary GH content concluding that pituitary GH content varied on a seasonal basis (Scruggs 1951;Swift and Pickford 1965;Bhargava and Raizada 1973;Kaul and Vollrath 1974). Subsequent development of radioimmunoassays has provided evidence that seasonal variations in blood GH levels do occur in fish (Marchant and Peter 1986).…”

mentioning

confidence: 99%

A Mammalian Growth Hormone‐Releasing Hormone Increases Serum Growth Hormone Levels and Somatic Growth at Suboptimal Temperatures in Tilapia

Kelly

Kohler

Grau

1996

J World Aquaculture Soc

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The effects of a mammalian growth hormone‐releasing hormone (GHRH), PrebGRF(1–78)OH (bGHRH), on growth and serum growth hormone (GH) levels were investigated in tilapias Oreochromis mossambicus andO. niloticus × O. aureus. Fish were injected intramuscularly or implanted intramuscularly (Silastic or cholesterol implants) with distilled water, 0.1 μg/kg bGHRH, 1.0 μg/kg bGHRH, 10.0 μg/kg bGHRH, or 100.0 μg/kg bGHRH and compared to untreated controls, fish implanted with 60 mg/kg 17α‐methyltestosterone (MT), or a combination of bGHRH concentrations plus either MT, 0.01 μg/kg of a thyroid hormone (T3), or 0.01 μg/kg of a glucocorticoid (DEX). The bGHRH increased serum GH levels in tilapia maintained at suboptimal temperatures (18 C). Serum GH levels were highest (5.3–0.45 ng/mL) for fish injected with 10.0 μg/kg bGHRH. Fish implanted with a Silastic implant containing 10.0 μg/kg bGHRH had significantly higher (4.35–0.35 ng/mL) serum GH levels than those with an equivalent dosage in a cholesterol implant. The addition of MT, thyroid hormones, and glucocorticoids did not increase serum GH levels above those obtained for fish receiving bGHRH alone. Tilapia reared at suboptimal temperatures and implanted with 10.0 μg/kg and 100.0 μg/kg bGHRH had significantly greater increases in weight and length than control fish. Fish implanted with bGHRH, MT or bGHRH plus MT had significantly higher moisture and protein content, while fat and ash contents were significantly lower than controls or sham‐implanted fish. Fish implanted with bGHRH or bGHRH plus MT had significantly higher gonadosomatic indices than fish implanted with MT alone, shams or non‐treated controls. This study demonstrates that a mammalian GHRH stimulates release of GH, promotes somatic and gonadal growth and may affect reproductive performance in tilapia.

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“…The factors inducing these cycles of activity may be mainly hormonal. The growth hormone has been shown to exhibit a circadian rhythm in the blood of fish (Leatherland et QZ., 1974) and a seasonal cycle of production in the pituitary (Swift & Pickford, 1965;Bhargava & Rhizada, 1973). Other hormones including corticosteroids, oestrogens, androgens, insulin and thyroxine have also been implicated in growth control (Daughaday et QZ., 1975).…”

Section: Discussionmentioning

confidence: 99%

Rhythmic growth activity in fish scales

Ottaway

1978

Journal of Fish Biology

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Changes in the growth of fish are reflected in the rate of growth of their scales. This produces the rings used in ageing temporate species. A technique has been devised for measuring the rate at which [14C] glycine is incorporated into isolated scales in vitro.This method has been used to investigate various rhythmic activities in fish growth. The results show that the amino acid is incorporated into at least two types of cell and that deposition in the scale occurs with at least two different rhythms with very different frequencies.

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Statistical Studies of the Seasonal Changes in the Pituitary Gland of Rasbora daniconius (Pisces: Cyprinidae)

Cited by 5 publications

References 0 publications

Seasonal changes in the pituitary‐ gonad axis of feral goldfish, Carassius auratus L., from Ontario, Canada

Seasonal changes in the pituitary‐ gonad axis of feral goldfish, Carassius auratus L., from Ontario, Canada

A Mammalian Growth Hormone‐Releasing Hormone Increases Serum Growth Hormone Levels and Somatic Growth at Suboptimal Temperatures in Tilapia

Rhythmic growth activity in fish scales

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