Endocrine factors, related

A number of endocrine factors have been linked to the incidence of breast cancer.5,6 Many of these relate to the total duration of menstrual life. Early menarche (prior to age 12) and late menopause (after age 55) increase a women s breast cancer risk. Similarly, investigators have reported that bilateral oophorectomy prior to age 35 reduces the relative risk of developing breast cancer. Nulliparity and a late age at first birth (greater than or equal to 30 years) have been reported to increase the lifetime risk of developing breast cancer twofold. 

It is well recognised that the growth rate can be affected by numerous intrinsic and extrinsic factors related to the host, such as host species or strain (733), host nutrition, endocrine status or environmental conditions (e.g. temperature), as well as the worm burden present. 

Powers, C.J., McLeskey, S.W., and Wellstein, A. 2000. Fibroblast growth factors, their receptors and signalling. Endocrine Related Cancer 1(3), 165-197. 

Not the least of the factors for consideration in evaluating a possible risk pertains to the characteristics of those persons exposed. A hazard does not become an actuality until there is a risk of human exposure. Consequently, in evaluating the risk, you must take into account those who are or might be exposed, not only in terms of numbers but also in relation to the realities of individual variation and predisposition. These considerations can be difficult in a political environment that demands equality. However, it should be recognized that not all persons are equal either in their predisposition towards an adverse response to a toxic assault or in the severity of their response to that assault. Differences in response can occur, for example, by reason of age, sex, and physical fitness. A classic example exists in the manufacture and processing of female endocrine hormones in which a woman, and particularly a pregnant woman, may be more at risk than a man under the same circumstances. Less dramatic, but... 

Rosmond R, Eriksson E, Bjorntorp P. Personality disorders in relation to anthropometric, endocrine and metabolic factors. J Endocrinol Invest 1999 22 279-288. 

JH III is sufficient to induce pheromone biosynthesis in starved I. pini and D. jeffreyi, suggesting a relatively simple endocrine regulation. However, starved I. paraconfusus cannot be induced to synthesize pheromone by JH III, despite the fact that HMG-R expression rises with JH III treatment. Pheromone biosynthesis in I. paraconfusus requires feeding (Seybold et al., 2000 Tillman et al., in preparation). Since HMG-R expression is apparently regulated similarly in both species, I. paraconfusus must require an additional signal in order to activate pheromone biosynthesis. The necessary factors are likely to act post-transcriptionally or post-translationally on HMG-R. These studies show that extending information from one species to another must be done with caution, as even closely related bark beetles seem to have very different regulatory schema. 

Turnbull, A.V. and Rivier, C. 1997. Corticotropin-releasing factor (CRF) and endocrine responses to stress CRF receptors, binding protein, and related peptides. Proc Soc Exp Biol Med 215 1. 

In many species, xenobiotic metabolism exhibits circadian and seasonal cycles. In wild populations, these cycles may be related to many factors including day length, diet, breeding cycles, and temperature. Since most laboratory animals are kept under controlled environmental conditions, they do not display seasonal changes in metabolism. However, they do exhibit circadian rhythms in activity and endocrine function... 

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