Relations entre le cycle hormonal cérébral et l'évolution ovocytaire chez Perinereis cultrifera grube (annélide polychète)

Patterns of cerebral endocrine activity innereis diversicolor (annelida: Polychaeta)

“…This result, in contrast to that above, is doubtless a reflection of a key event taking place at this stage of the life cycle. Similar findings have been reported with respect to regeneration in N. diversicolor (Golding, 1967b) and Platynereis dumerilii (Hofmann, 1976), and maturation in Perinereis cultrifera (Porchet, 1970).…”

“…In N. diversicolor, the first stage has been said to be characterized by the refractory character of the oocytes to hormone deprivation (Clark and Ruston, 1963). However, our observations demonstrate that oocytes less than 60 pm in diameter degenerate following decerebration of the animal (although this is preceded by an initial phase of accelerated growth), as they do in Nereis grubei (Schroeder, 1971), Perinereis cultrifera (Porchet, 1970), and, probably, Platynereis dumerilii (Hauenschild, 1964).…”

“…N. grubei and P. cultrifera), a third stage can be distinguished, during which accelerated but normal development is possible (Porchet, 1970;Schroeder, 1971). In contrast, acceleration of oocyte growth in N. diversicolor, which can be obtained until oocytes reach 150 (Jt.…”

The activation of gamete migration, maturation and spawning inPectinaria gouldii

“…In the nereids, the stimulus is provided by a Downloaded by [Purdue University] at 09:43 12 April 2015 hormone derived from the cerebral (supraesophageal) ganglion which inhibits or regulates gamete formation in the coelom. Evidence from brain implants made into decerebrated females of Perinereis indicates that a decrease in the inhibitory or 'juvenile' hormone secreted by the cerebral ganglion occurs as gamete maturation continues [ 13]. These and other experiments have led to the hypothesis [14] that a single neurosecretory substance inhibits oogenesis at high concentrations, but permits and is necessary for normal oocyte development at lower concentrations.…”

DEVELOPMENT OF THE NUCLEAR STRUCTURE AND METABOLISM DURING OOGENESIS OFPERINEREIS CULTRIFERA(ANNELIDA, POLYCHAETA)

“…In the laboratory, the oocyte diameter of each animal was determined by measuring several oocytes obtained by coelomic puncture [13]. Oogenesis can be subdivided into 4 stages: previtellogenesis (20-40 J.Lm), vitellogenesis (60-100 J.Lm), development of cortical alveoli (130-180 J.Lm) and maturity (220-240 J.Lm).…”