These studies examined the role of perinatal androgen
in the development of neuroendocrine and behavioral
characteristics of gray-tailed voles, Microtus
canicaudus. When mature, females exhibited alternating
vaginal smear patterns or persistent vaginal
cornification; estrogen and progesterone concentrations
were not correlated with vaginal smear patterns. Corpora
lutea were not observed in...
In the wild, when an animal is exposed to predators or harsh conditions, the stress
response is often associated with fleeing behaviors, which are seen as increased
locomotor behavior. Handling-stress procedures and intracerebroventricular (icy)
injection of corticotropin-releasing factor (CRF) have both been shown to cause an
increase in locomotor activity...
In addition to the well-characterized genomic mechanism of steroid action that uses
intracellular receptors, steroid hormones also signal through nongenomic processes
that use membrane receptors. A membrane receptor for corticosterone (CORT) has
been described in brains of the roughskin newt (Taricha granulosa). This receptor is
believed to be a G-protein...
One hypothesis proposed to explain how the endocrine
system controls reproductive cycles in seasonally breeding
animals is that the hypothalamus undergoes seasonal
changes in sensitivity to negative feedback by gonadal
steroids. The result is seasonal changes in the secretion
of luteinizing hormone-releasing hormone (LHRH) and
gonadotropin secretion. The present experiments...