Prolactin induces tuberoinfundibular dopaminergic neurone differentiation in Snell dwarf mice if administered beginning at 3 days of age.

The hypothalamic tuberoinfundibular dopaminergic (TIDA) neurones secrete dopamine, which inhibits prolactin secretion. TIDA neurone numbers are deficient in Ames (df/df) and Snell (dw/dw) dwarf mice, which lack prolactin, growth hormone and thyroid-stimulating hormone. Prolactin therapy initiated before 21 days maintains normal-sized TIDA neurone numbers in df/df mice and, when initiated as early as 7 days, maintains the maximum TIDA neurone numbers observed in dw/dw development, which are decreased compared to those in normal mice. The present study investigated the effect of prolactin dose and species on TIDA neurone development. Snell dwarf and normal mice were treated with saline, 5 microg of ovine prolactin (oPRL), 50 microg of oPRL, or 50 microg of recombinant mouse prolactin (rmPRL) beginning at 3 days of age. Brains were analysed at 45 days using catecholamine histofluorescence, and immunohistochemistry for tyrosine hydroxylase or bromodeoxyuridine. Normal mice had greater (P

Maternal serum corticotropin-releasing hormone at midgestation in Hispanic and white women.

OBJECTIVE: Maternal circulating corticotropin-releasing hormone analysis at midgestation has been proposed as a parameter for the prediction of preterm birth. However, one recent study has reported that corticotropin-releasing hormone concentrations at midgestation differ in the black and white populations. These findings led us to investigate whether other populations have differing concentrations of maternal circulating corticotropin-releasing hormone that may require reference to specific population-based medians for optimal midgestational screening. METHODS: In this study we have defined the mean and median concentrations of maternal circulating corticotropin-releasing hormone in Hispanic and white populations at each gestational week from 14 to 18 weeks of pregnancy, using a sensitive and specific radioimmunoassay. RESULTS: Corticotropin-releasing hormone concentrations were found to be significantly lower in the Hispanic population as compared with whites at 16, 17, and 18 weeks' gestation. The distribution of corticotropin-releasing hormone, expressed as multiples of the median (MoM) using the appropriate ethnicity-related median, was estimated for each gestational week and for each population. No differences were observed in the distribution of the ethnicity-adjusted MoM for Hispanics and whites. CONCLUSION: These data demonstrate that ethnicity is a significant factor affecting corticotropin-releasing hormone concentrations at midgestation in the Hispanic and white populations. The use of ethnicity-specific medians to estimate the ethnicity-specific MoM for the corticotropin-releasing hormone concentrations may enhance the predictive value of midgestational maternal corticotropin-releasing hormone as a screening parameter for the prediction of preterm birth.