Bill R. Hopper

Altered Neuroendocrine Status of Middle-Aged Rats Prior to the Onset of Senescent Anovulation

The incidence of senescent anovulation (constant estrus) in female rats increases sharply in the age interval 10--14 months. We have compared the neuroendocrine status of 12-month-old rats, which were still cycling, with that of 6-month-old rats in the reproductive prime. Norepinephrine content in the median eminence of the hypothalamus and circulating levels of FSh and androstenedione were significnatly higher in middle-aged rats (12 months old) than in young controls (6 months old). These increases were selective, in that ten other neuroendocrine parameters measured were unchanged. These results indicate that changes occur at multiple levels of the neuroendocrine system during the transitional phase prior to the onset of senescent anovulation.

Fetal lung maturation: Amniotic fluid catecholamines, phospholipids, and cortisol

The identification of β -adrenergic receptors in the fetal lung led us to investigate amniotic fluid catecholamine levels in relation to other indices of fetal pulmonary maturity in late pregnancies (n=62). Significant correlations were found between the percentage of phosphatidylglycerol and concentrations of norepinephrine (r=0.44, p

Fetal Lung Maturation: Amniotic Fluid Catecholamines, Phospholipids, and Cortisol

The identification of beta-adrenergic receptors in the fetal lung led us to investigate amniotic fluid catecholamine levels in relation to other indices of fetal pulmonary maturity in late pregnancies (n = 62). Significant correlations were found between the percentage of phosphatidylglycerol and concentrations of norepinephrine (r = 0.44, p less than 0.001), its intraneuronal deaminated metabolite 3,4-dihydroxyphenylglycerol (DOPEG; r = 0.74, p less than 0.0001), epinephrine (4 = 0.43, p less than 0.001), and cortisol (r = 0.78, p less than 0.001). Highly significant elevations of these substances were noted with accelerated pulmonary maturation. Lecithin/sphingomyelin (L/S) ratios showed a significant correlation with cortisol levels (r = 0.50, p less than 0.001); however, significant associations between L/S ratios and catecholamine levels were found only when complicated pregnancies were excluded. These findings support the contention that fetal contention that fetal adrenergic activity participates in the process of pulmonary maturation.