Effects of Hypothalamic Stimulation on Prolactin Secretion in Steroid Treated Rats
| Autor: | James A. Clemens, Michael E. Roush, Carl J. Shark, William A. Tandy |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
medicine.medical_specialty
medicine.drug_class Hypothalamus Stimulation Stereotaxic Techniques Prolactin cell chemistry.chemical_compound Endocrinology Internal medicine medicine Animals Castration Progesterone Estradiol Chemistry Ovary Electric Stimulation Prolactin Rats Estrogen Median eminence Ovariectomized rat Estradiol benzoate Female |
| Zdroj: | Endocrinology. 89:1317-1320 |
| ISSN: | 1945-7170 0013-7227 |
| Popis: | A study was performed to deter- mine the influence of ovarian steroids on the ability of an electrochemical stimulus or sham stimulus placed in the median eminence arcuate area to elicit prolactin release in ovariectomized rats. Both sham stimulation and electrochemical stimulation caused prolactin release in rats treated with 2 \ig of estradiol benzoate (EB). Rats receiv- ing simultaneous administration of 4 mg of pro- gesterone and 2 u,g of EB developed high serum prolactin levels in response to electrochemical stimulation, but had unchanged levels after sham stimulation. The reasons for this may be that the urethane anesthesia combined with stereotaxic immobiliza- tion and surgery created a stressful condition that influenced prolactin secretion in these animals. Estrogen appeared to act by lowering the threshold for excitation of neurons that respond to stressful stimuli, and also lower thresholds of neurons that inhibit prolactin inhibiting factor (PIF) secreting neurons or stimulate prolactin stimulating factor (PSF) neurons. Progesterone may have raised the threshold for excitation of neurons in the CNS which are capable of eliciting prolactin release in response to stress. The possibility also exists that EB may have a direct action on the pituitary to amplify the effects of small changes in hypo- thalamic inhibiting and/or stimulating factor secretion. (Endocrinology 89: 1317, 1971) T>ROLACTIN concentration in the anterior •*• pituitary (AP) of the rat markedly increases |
| Databáze: | OpenAIRE |
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