Background: This study investigated the effects of estradiol on plasma calcium and prolactin cells of Heteropneustes fossilis kept in calcium-deficient and normal freshwater. Methods: Fish were deprived of food and divided into groups AD. Group A and B were kept in artificial freshwater with normal electrolytes. Group C and D were maintained in calcium-deficient freshwater. Vehicle was administered to groups A and C. Groups B and D were injected with estradiol. Plasma calcium levels and prolactin cells were studied after 1, 3, 5, 10 and 15 days. Results: Normal-calcium freshwater: In group A calcium levels remained unaffected. In group B, estradiol provoked hypercalcemia from day 3 to 10 although calcium decreased after day 15. Prolactin cells in group B became degranulated after 10day. Nuclear volume increased from day 10 onwards. Calcium-deficient freshwater: Calcium levels in group C decreased from day 1 to 3 thereafter increased from day 5 to 15. Plasma calcium of group D increased from day 3 to 15. In group C prolactin cells exhibited hyperactivity on day 3 and degranulation on day 5. Nuclear volume increased from day 5 onwards. On day 10 and 15 certain cells became degenerated. In group D degranulation of prolactin cells began on day 3 which proceeded to complete degranulation on day 10. Nuclear volume increased from day 5 onwards. Conclusions: Estradiol enhanced prolactin production and increased blood calcium in fooddeprived fishes kept in calcium-deficient medium suggesting that calcium needed for elevation of blood calcium was derived from internal sources.
Adult fish Heteropneustes fossilis were divided into 4 groups –(i) Group A: kept in artificial freshwater and daily injected intraperitoneally with vehicle; (ii) Group B: kept in artificial freshwater and were daily injected intraperitoneally with 0.1 mg/100 g body wt of oProlactin; (iii) Group C: maintained in calcium-deficient freshwater and daily injected intraperitoneally with vehicle; (iv) Group D: kept in calcium-deficient freshwater and daily injected intraperitoneally with 0.1 mg/100 g body wt of oProlactin. Blood samples were taken 2 h after the last injection on 1, 3, 5, 10 and 15 days of the treatment. Plasma calcium levels were analyzed. The corpuscles of Stannius (CS) were fixed for histological studies. Artificial freshwater: The plasma calcium levels of vehicle-injected specimens (group A) remained unaltered throughout the experiment. Following prolactin treatment (group B) the plasma calcium levels progressively increased from day 3 to day 5. The values became normocalcemic at day 10 and day 15. After day 5 following prolactin administration (group B), the nuclear volume of AF-positive cells increased and the cells were seen degranulated. After day 10, there was an increased dilatation of sinusoids and the nuclear volume of AF-positive cells showed further increase. On day 15, these changes were exaggerated. The AFnegative cells of the corpuscles of Stannius of prolactin-treated fish (group B) showed no change in their histological structure and nuclear volume. Calcium-deficient freshwater: The plasma calcium level decreased in vehicle-injected fish (group C) from day 1 to day 3 (as compared to level of the fish kept in artificial freshwater). Thereafter, the level increased from day 5 resulting in hypercalcemia at day 10 and day 15. In prolactin treated fish (group D) the plasma calcium level indicated progressive increase from day 5 to day 15. In the vehicle-injected fish (group C) the AF-positive cells of corpuscles of Stannius showed accumulati
The present study includes the responses of plasma calcium and prolactin cells of a freshwater teleost, Heteropneustes fossilis injected with prolactin and maintained in artificial freshwater or calcium-deficient freshwater. Fish were divided into groups A-D. Groups A and B were kept in artificial freshwater. Groups C and D were maintained in calcium-deficient freshwater. Vehicle was administered to groups A and C. Groups B and D were injected with prolactin. Plasma calcium levels and prolactin cells were studied after 1, 3, 5, 10 and 15 days.In group B, prolactin treatment provoked hypercalcemia from day 3 to day 5; however, the values became normocalcemic at day 10 and day 15.A significant decrease in the nuclear volume of prolactin cells has been noticed in 5 day prolactin treated fish (group B). This response progresses till day 15. Moreover, on day 10 and day 15, depletion in the cytoplasmic granulation has been observed.In vehicle-injected fish (group C) the plasma calcium level decreases from day 1 to day 3 (as compared to level of the fish kept in artificial freshwater). Thereafter, the level records an increase from day 5 resulting in hypercalcemia at day 10 and day 15. In prolactin treated fish (group D) the plasma calcium level shows no change up to day 3 as compared to the vehicle-injected group (group C). From day 5 to day 15, the value indicates progressive increase in plasma calcium level.The prolactin cells of vehicle-injected fish (group C) exhibit hyperactivity on day 3 which is evident by the degranulation, hyperchromaticity of the nuclei and increased nuclear volume. Few cells are seen to degranulate completely after day 5. From day 5 to day 15, the nuclear volume is further increased. Certain cells are seen degenerating on day 10 and day 15.The prolactin cells of prolactin treated fish (group D) have not shown any change till day 5. Between day 10 and day 15 there is a progressive decrease in the nuclear volume. Moreover, vacuolization and degeneration have also been noticed.
Effects of prolactin administration were investigated on plasma calcium, and ultimobranchial gland (UBG) of a freshwater catfish, Heteropneustes fossilis. Fish were divided into groups AD. Group A and B were kept in artificial freshwater with normal electrolytes. Group C and D were maintained in calcium-deficient freshwater. Vehicle was administered to groups A and C. Groups B and D were injected with prolactin. Plasma calcium, inorganic phosphate levels and UBG were studied after 1, 3, 5, 10 and 15 days. Prolactin treatment caused hypercalcemia from day 3 to day 10; however, the values become narmocalcemic at day 10 and day 15. Similarily, from day 5 onwards a progressive increase in the plasma phosphate level has been noticed. UBG cells of prolactin-treated fish (kept in artificial freshwater) exhibit increased nuclear volume and poor staining response (from day 5 to 10). On day 15 few degenerating cells and a decline in nuclear volume have been noticed. In vehicle-injected fish (group C) the plasma calcium level decreases from day 1 to day 3 (as compared to level of the fish kept in artificial freshwater). Thereafter, the level records an increase from day 5 resulting in hypercalcemia at day 10 and day 15. In prolactin treated fish (group D) the plasma calcium level shows no change up to day 3 as compared to the vehicle-injected group (group C). From day 5 to day 15, the value indicates progressive increase in plasma calcium level. The plasma phosphate level of vehicle-injected fish (group C) remains unaltered on day 1. A progressive hypophosphatemia has been observed between day 3 and day 5. Thereafter, the values indicate a tendency to increase. Up to day 3 the plasma phosphate level of prolactin-injected fish (group D) is almost same as compared to that of vehicle-injected specimens (group C). Thereafter, the level indicates a tendency to increase thus resulting in hyperphosphatemia 5 day onwards.
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