Effect of passive immunization against leptin on ovarian follicular development in prepubertal mice.

Leptin has been demonstrated to be essential for reproduction. However, all the relevant studies reported to date have investigated either the effect of a complete absence of leptin both centrally and peripherally, or excess leptin administration. The aim of this present study was to investigate the effect of reducing peripheral leptin concentrations on ovarian follicular development in prepubertal animals via administration of an anti-leptin antibody.

An Investigation of Hair Cortisol Concentration Across Body Sites and within Hair Shaft.

Cortisol concentrations in hair collected from young male and female adults were assayed and compared for differences along shaft length and between body sites. No significant differences were found between hair shaft sites, supporting a model of the hair shaft as "alive" and responsive to environmental demand in terms of cortisol production. Hair taken from forearms had significantly higher concentrations of cortisol than hair from lower legs, suggesting a localized hair cortisol response and verifying previous findings.

Diurnal Variation in Peripheral (Hair) vs Central (Saliva) HPA Axis Cortisol Concentrations.

Cortisol concentrations in hair and saliva collected from male and female adults over a 15-hour period were compared for differences in overall level and cyclic pattern. Typical diurnal fluctuations were noted for both salivary and hair cortisol, with some individual differences that are congruent with the previous literature. Issues of the link between central and peripheral HPA axes are raised for discussion and further investigation, and hypothetical explanations for the diurnal variability shown in these two sets of cortisol secretion patterns are discussed from an evolutionary advantage perspective.