Endocrinology
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To investigate the role of GnRH in regulating the synthesis and secretion of gonadotropins, GnRH (250 ng/6 min every other hour for 7 days) or saline was administered to ovariectomized (OVX) ewes after hypothalamic-pituitary disconnection (HPD). Blood samples were collected from all HPD ewes on the day before and the day after HPD and on days 1 and 7 of GnRH or saline. At the end of day 7, anterior pituitary glands were removed for analysis of hormone, receptor, and mRNA content. ⋯ Serum PRL concentrations in all ewes were higher (P less than 0.05) after HPD than before HPD. Serum GH concentrations in all ewes were similar (P greater than 0.05) before and after HPD. Since synthesis and secretion of GH and PRL were not diminished after HPD, it was considered that the pituitary gland remained viable and functioned independently of hypothalamic input in OVX ewes after HPD.(ABSTRACT TRUNCATED AT 400 WORDS)