Neuroendocrine control of vitellogenesis In the spiny lobster Panulirus homarus (Linnaeus, 1758)

Fernandez, Rachel (2002) Neuroendocrine control of vitellogenesis In the spiny lobster Panulirus homarus (Linnaeus, 1758). PhD thesis, PGPM, Central Marine Fisheries Research Institute.

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Abstract

The female reproductive system of the spiny lobster Panulirus homarus ( Linnaeus, 1758 ) was investigated histomorphologically and ultrastructurally to study the process of ovarian development and vitellogenesis in detail. The general morphology of the central nervous system was traced out. The neurosecretory cells in the optic ganglia, supraoesophageal ganglion and thoracic ganglia were identified, classified and mapped. The optic ganglia have six types of neurosecretory cells whereas both the supra oesophageal ganglion and the thoracic ganglia have eight neurosecretory cell types. Secretory cycle of the neurosecretory cell types was studied and it was classified into four phases, viz. synthetic phase, vacuolar phase, secretory phase and quiscent phase. Secretory status of the various neurosecretory cell types was studied at different stages of ovarian development. The vitellogenin unit from the haemolymph and the vitellin unit from the ovary was isolated and characterized. The immunodiffusion precipitation studies and the ultrastructural studies reveal that there is exogenous vitellogenin synthesis in Panulirus homarus. The hepatopancreas and the adipose tissue are likely to be the sites of vitellogenin synthesis. Bilateral eyestalk ablation studies conducted on the early and late intermoult stages show simultaneous acceleration of the somatic growth and reproductive processes with higher emphasis for ovarian growth in lobsters ablated in the early intermoult phase and lower activity in those ablated in the late intermoult phase. Ablation in late intermoult phase resulted in faster entry into the premoult stage. Administration ofthe aqueous extracts of supraoesophageal ganglia and the thoracic ganglia from the maturing female lobsters accelerated vitellogenesis when they were injected into the lobsters. Injection of neuroregulators accelerated vitellogenic process in those injected with 5-hydroxytryptamine unlike the dampened effect in lobsters administered with dopamine.

Item Type:Thesis (PhD)
Supervisor(s):Radhakrishnan, E V
Uncontrolled Keywords:Neuroendocrine control; vitellogenesis spiny lobster; Panulirus homarus
Subjects:Fish and Fisheries > Fish physiology
Theses
Crustacean Fisheries > Lobsters
Divisions:CMFRI-Cochin > Marine Capture > Crustacean Fisheries
ID Code:7133
Deposited By:Dr. V Mohan
Deposited On:27 Jan 2011 15:17
Last Modified:20 Jan 2014 13:42

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