title: Progestin receptor-containing cells in guinea pig hypothalamus: Afferent connections, morphological characteristics, and neurotransmitter content.
abstract: Progestin receptor-containing cells in the guinea pig hypothalamus were examined by immunocytochemical methods to characterize their morphological properties, afferent connections, and neurotransmitter content. Through the use of a monoclonal mouse antibody raised against the rabbit uterine progestin receptor, progrestin receptor-containing cells were identified after estrogen treatment in the retrochiasmatic area, medial and periventricular preoptic area, arcuate nucleus, and lateral hypothalamic area including the ventrolateral aspect of the ventromedial nucleus. Ultrastructural analysis revealed a heterogeneously distributed immunoreaction product restricted to the cell nucleus. A similar pattern of nuclear progestin receptor immunostaining was observed in the uterine endometrium. Progesterone administration intensified progestin receptor immunostaining, without appearing to alter the distribution of immunoreaction product within the cell nucleus. No immunostaining was observed in sections from ovariectomized (OVX) or OVX progesterone-treated animals. Hypothalamic sections from estrogen/progesterone-treated guinea pigs were double-immunostained for progestin receptor and neurotransmitter- or neuropeptide-related antigens. Synaptic contacts of tyrosine hydroxylase-, glutamic acid decarboxylase (GAD)-, serotonin-, adrenocorticotropic hormone-, and cholecystokinin-immunoreactive axon terminals were found on progestin receptor-immunopositive neurons. In addition, nonconventional junctional complexes were observed between TH-immunoreactive soma and the soma of progestin receptor- immunoreactive neurons. No evidence of immunostaining for neurotransmitters or neuropeptides other than GAD was observed in progestin receptor- immunoreactive neurons. In addition to ultrastructural characterization of progestin receptor immunoreactivity in the guinea pig hypothalamus, these studies demonstrate, for the first time, direct connections of neurotransmitter/neuropeptide systems involved in neuroendocrine regulation with steroid receptor-containing neurons in the rodent hypothalamus. Estrogen/progesterone-sensitive cells in the hypothalamus may act as centers for the integration of hormonal and neural influences on the control of reproductive function.
authors.affiliation: Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut 06510, USA; Section of Neuroanatomy, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Brown
authors.forename: N J
authors.initials: NJ
authors.lastname: Maclusky
authors.forename: C
authors.initials: C
authors.lastname: Leranth
authors.forename: M
authors.initials: M
authors.lastname: Shanabrough
authors.forename: F
authors.initials: F
authors.lastname: Naftolin