James L Voogt

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Lactation is a state of hyperprolactinemia resulting in part from suppressed tuberoinfundibular dopaminergic (TIDA) neuronal activity. The suckling stimulus contributes to this suppression despite the fact that the TIDA neurons are a potential site for PRL feedback to increase neuronal activity. This study examined the influence of PRL feedback and the(More)
The effects of experimentally produced hypoprolactinemia and hyperprolactinemia on tyrosine hydroxylase (TH) mRNA signal levels were examined in dopaminergic neurons ovariectomized rats. TH mRNA signal levels and relative TH quantity in the arcuate nuclei, zona incerta, and substantia nigra were evaluated by in situ hybridization and immunocytochemistry,(More)
Central catecholaminergic systems play an important role in the control of reproductive activities including sexual behavior, luteinizing hormone (LH) and prolactin secretion. It has been reported that catecholaminergic neurons in the locus coeruleus (A6) are activated by mating in rabbits and ferrets, animals known as reflex ovulators. This study used Fos(More)
The endogenous opioid peptides have been implicated in the control of the suckling-induced PRL rise during lactation. This study examined the role of the endogenous opioid peptides in suppressing tuberoinfundibular dopaminergic neuronal activity during lactation. In the first experiment, lactating rats were constantly exposed to pups. Naloxone (NAL; 60(More)
Using in situ hybridization and immunocytochemistry, this study examined the tyrosine hydroxylase (TH) mRNA signal levels and immunostaining in the arcuate nuclei of the hypothalamus, zona incerta and substantia nigra of male and female rats during neonatal, peripubertal and adult life. The catalytic activity of TH in the stalk-median eminence was also(More)
This study examined the responsiveness of dopaminergic neurons to PRL and the expression of PRL receptors in fetal hypothalamic cells. Hypothalamic cells were cultured in medium containing 5 or 25 mM potassium (K+) with or without 5% FBS. Rat PRL (rPRL) treatment (10-1000 ng/ml) for 10 days increased tyrosine hydroxylase (TH) activity 1.6- to 1.8-fold in(More)
In order to identify the distribution of prolactin-releasing peptide (PrRP) mRNA in the rat brain, we independently cloned cDNA of PrRP. Brains were removed from three adult males, and brains from three females each at 0200 and 1400 h on day 7 of pregnancy were obtained. By the nonradioactive in situ hybridization method, the location of PrRP mRNA was(More)
The effects of aging in the female rat were analyzed in terms of tyrosine hydroxylase (TH) gene expression and serum prolactin levels. The number of tuberoinfundibular dopaminergic (TIDA) neurons and the concentration of TH mRNA per cell was greater in 16- to 18-month-old rats than in 25-month-old rats. The amount of TH immunostaining was more intense in(More)
In order to understand the mechanism by which thyroid hormones alter prolactin (PRL) secretion, we investigated the role of tuberoinfundibular dopamine (TIDA) neurons and pituitary and hypothalamus vasoactive intestinal peptide (VIP) in thiouracil- (0. 03% in drinking water for 16 days) induced-hypothyroid adult female rats. The intromission threshold for(More)