Cyclic juvenile hormone biosynthesis in the cockroach, Blattella germanica: effects of ovariectomy and corpus allatum denervation.

نویسندگان

  • M Gadot
  • A S Chiang
  • E L Burns
  • C Schal
چکیده

The corpora allata (CA) of ovariectomized adult Blattella germanica females exhibited delayed but high rates of juvenile hormone biosynthesis in vitro. Using the onset of sexual receptivity as a probe of the degree of CA activation in females, we demonstrated at least one cycle of CA activity in the experimentally synchronized ovariectomized females. Following their activation, the CA exhibited a partial and transient decline in activity, but in contrast to the CA of intact females, this decline was not accompanied by a regression in CA volume. CA of intact and ovariectomized females that were denervated from the brain were activated, but the subsequent decline in CA activity at the end of the cycle was prevented in ovariectomized females. The presence of an egg-case suppressed the reactivation of the inactive CA in intact females but not in CA-denervated females. We conclude that activation of the CA in B. germanica is not dependent upon either the presence of the ovary or intact nervous connections between the CA and the brain. The brain exerts a partial inhibition on CA activity through intact nerves which is relieved (by disinhibition) in the presence of a young ovary but is enhanced and sustained in the presence of the egg-case. Inhibition of the CA also occurs independently of nervous connections with the brain through factors that originate in the mature ovary and affect both CA activity and morphology.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Ovarian Regulation of Cyclic Changes in Size and Activity of Corpus Allatum Cells in Blattella Germanica

The roles of the ovary and egg case in the regulation of the development and activity of the corpora allata were studied in Blattella germanica adult females. The corpora allata of ovariectomized females exhibit a delayed pattern of development and activity compared with intact females. Implantation of a young ovary into ovariectomized females resulted in a faster activation of the corpora alla...

متن کامل

Cyclic Volumetric Changes in Corpus Allatum Cells in Relation to Juvenile Hormone Biosynthesis During Ovarian Cycles in Cockroaches

Development and activity of the corpora allata (CA) were investigated in adult female Blattella germanica and Supella longipalpa. These two cockroach species differ in their reproductive modes, with relatively uninterrupted cycles of oocyte development in S. longipalpa and discrete patterns of oocyte development which are interrupted by pregnancy in B. germmica. During ovarian cycles in both co...

متن کامل

Developmental regulation of juvenile hormone synthesis: ovarian synchronization of volumetric changes of corpus allatum cells in cockroaches.

The corpus allatum (CA) cells of adult Blattella germanica females undergo cyclic volumetric changes in relation to juvenile hormone (JH) synthesis. In intact females the size of CA cells changes synchronously during the gonotrophic cycle, resulting in cyclic JH synthesis. In ovariectomized females volumetric changes among CA cells become asynchronous, resulting in highly variable but high rate...

متن کامل

Farnesoic Acid-stimulated Rates of Juvenile Hormone Biosynthesis during the Gonotrophic Cycle in Blattella Germanica

Juvenile hormone III biosynthesis in vitro by the corpora allata of adult female Bluttellu germanica is precisely correlated with the gonotrophic cycle. Farnesoic acid-stimulated rates of juvenile hormone synthesis are always higher than the corresponding basal rates, and follow the same pattern of cyclic changes during oijcyte maturation. Both basal and farnesoic acid-stimulated rates decline ...

متن کامل

Reproductive Biology of the German Cockroach, Blattella germanica: Juvenile Hormone as a Pleiotropic Master Regulator

Juvenile hormone (JH) exerts major pleiotropic effects on cockroach development and reproduction. The production of JH by the corpora allata (CA) in the adult female German cockroach, Blattella germanica, is dependent upon and modulated by both internal and environmental stimuli. Mating, intake of highquality food, social interactions, and the presence of vitellogenic ovaries facilitate JH synt...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • General and comparative endocrinology

دوره 82 2  شماره 

صفحات  -

تاریخ انتشار 1991